Actions System + UI (#2710)

Co-authored-by: Vera Aguilera Puerto <6766154+Zumorica@users.noreply.github.com>

Content.Client/ClientContentIoC.cs

@@ -12,6 +12,7 @@ using Content.Client.UserInterface;
 using Content.Client.UserInterface.AdminMenu;
 using Content.Client.UserInterface.Stylesheets;
 using Content.Client.Utility;
+using Content.Shared.Actions;
 using Content.Shared.Interfaces;
 using Content.Shared.Alert;
 using Robust.Shared.IoC;
@@ -39,6 +40,7 @@ namespace Content.Client
             IoCManager.Register<IStationEventManager, StationEventManager>();
             IoCManager.Register<IAdminMenuManager, AdminMenuManager>();
             IoCManager.Register<AlertManager, AlertManager>();
+            IoCManager.Register<ActionManager, ActionManager>();
             IoCManager.Register<IClientAdminManager, ClientAdminManager>();
             IoCManager.Register<EuiManager, EuiManager>();
         }

Content.Client/EntryPoint.cs

@@ -13,6 +13,7 @@ using Content.Client.StationEvents;
 using Content.Client.UserInterface;
 using Content.Client.UserInterface.AdminMenu;
 using Content.Client.UserInterface.Stylesheets;
+using Content.Shared.Actions;
 using Content.Shared.GameObjects.Components;
 using Content.Shared.GameObjects.Components.Cargo;
 using Content.Shared.GameObjects.Components.Chemistry;
@@ -157,6 +158,7 @@ namespace Content.Client
             IoCManager.Resolve<IAdminMenuManager>().Initialize();
             IoCManager.Resolve<EuiManager>().Initialize();
             IoCManager.Resolve<AlertManager>().Initialize();
+            IoCManager.Resolve<ActionManager>().Initialize();
 
             _baseClient.RunLevelChanged += (sender, args) =>
             {

Content.Client/GameObjects/Components/HUD/Inventory/ClientInventoryComponent.cs

@@ -20,10 +20,13 @@ namespace Content.Client.GameObjects.Components.HUD.Inventory
     /// A character UI which shows items the user has equipped within his inventory
     /// </summary>
     [RegisterComponent]
+    [ComponentReference(typeof(SharedInventoryComponent))]
     public class ClientInventoryComponent : SharedInventoryComponent
     {
         private readonly Dictionary<Slots, IEntity> _slots = new();
 
+        public IReadOnlyDictionary<Slots, IEntity> AllSlots => _slots;
+
         [ViewVariables] public InventoryInterfaceController InterfaceController { get; private set; } = default!;
 
         private ISpriteComponent? _sprite;
@@ -70,6 +73,11 @@ namespace Content.Client.GameObjects.Components.HUD.Inventory
             }
         }
 
+        public override bool IsEquipped(IEntity item)
+        {
+            return item != null && _slots.Values.Any(e => e == item);
+        }
+
         public override void HandleComponentState(ComponentState? curState, ComponentState? nextState)
         {
             base.HandleComponentState(curState, nextState);

Content.Client/GameObjects/Components/HUD/Inventory/HumanInventoryInterfaceController.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 using Content.Client.UserInterface;
 using Content.Client.Utility;
 using JetBrains.Annotations;
@@ -84,6 +85,16 @@ namespace Content.Client.GameObjects.Components.HUD.Inventory
         public override SS14Window Window => _window;
         private HumanInventoryWindow _window;
 
+        public override IEnumerable<ItemSlotButton> GetItemSlotButtons(Slots slot)
+        {
+            if (!_inventoryButtons.TryGetValue(slot, out var buttons))
+            {
+                return Enumerable.Empty<ItemSlotButton>();
+            }
+
+            return buttons;
+        }
+
         public override void AddToSlot(Slots slot, IEntity entity)
         {
             base.AddToSlot(slot, entity);

Content.Client/GameObjects/Components/HUD/Inventory/InventoryInterfaceController.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using Content.Client.UserInterface;
 using Content.Shared.GameObjects.Components.Inventory;
 using Content.Shared.Input;
@@ -53,6 +54,10 @@ namespace Content.Client.GameObjects.Components.HUD.Inventory
         {
         }
 
+        /// <returns>the button controls associated with the
+        /// specified slot, if any. Empty if none.</returns>
+        public abstract IEnumerable<ItemSlotButton> GetItemSlotButtons(EquipmentSlotDefines.Slots slot);
+
         public virtual void AddToSlot(EquipmentSlotDefines.Slots slot, IEntity entity)
         {
         }

Content.Client/GameObjects/Components/Items/HandsComponent.cs

@@ -15,6 +15,7 @@ namespace Content.Client.GameObjects.Components.Items
 {
     [RegisterComponent]
     [ComponentReference(typeof(ISharedHandsComponent))]
+    [ComponentReference(typeof(SharedHandsComponent))]
     public class HandsComponent : SharedHandsComponent
     {
         [Dependency] private readonly IGameHud _gameHud = default!;
@@ -31,6 +32,18 @@ namespace Content.Client.GameObjects.Components.Items
 
         [ViewVariables] public IEntity? ActiveHand => GetEntity(ActiveIndex);
 
+        public override bool IsHolding(IEntity entity)
+        {
+            foreach (var hand in _hands)
+            {
+                if (hand.Entity == entity)
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+
         private void AddHand(Hand hand)
         {
             _sprite?.LayerMapReserveBlank($"hand-{hand.Name}");

Content.Client/GameObjects/Components/Mobs/Actions/ActionAssignment.cs

@@ -0,0 +1,90 @@
+using System;
+using Content.Shared.Actions;
+using Robust.Shared.GameObjects;
+
+namespace Content.Client.GameObjects.Components.Mobs.Actions
+{
+    public struct ActionAssignment : IEquatable<ActionAssignment>
+    {
+        private readonly ActionType _actionType;
+        private readonly ItemActionType _itemActionType;
+        private readonly EntityUid _item;
+        public Assignment Assignment { get; private init; }
+
+        private ActionAssignment(Assignment assignment, ActionType actionType, ItemActionType itemActionType, EntityUid item)
+        {
+            Assignment = assignment;
+            _actionType = actionType;
+            _itemActionType = itemActionType;
+            _item = item;
+        }
+
+        /// <param name="actionType">the action type, if our Assignment is Assignment.Action</param>
+        /// <returns>true only if our Assignment is Assignment.Action</returns>
+        public bool TryGetAction(out ActionType actionType)
+        {
+            actionType = _actionType;
+            return Assignment == Assignment.Action;
+        }
+
+        /// <param name="itemActionType">the item action type, if our Assignment is Assignment.ItemActionWithoutItem</param>
+        /// <returns>true only if our Assignment is Assignment.ItemActionWithoutItem</returns>
+        public bool TryGetItemActionWithoutItem(out ItemActionType itemActionType)
+        {
+            itemActionType = _itemActionType;
+            return Assignment == Assignment.ItemActionWithoutItem;
+        }
+
+        /// <param name="itemActionType">the item action type, if our Assignment is Assignment.ItemActionWithItem</param>
+        /// <param name="item">the item UID providing the action, if our Assignment is Assignment.ItemActionWithItem</param>
+        /// <returns>true only if our Assignment is Assignment.ItemActionWithItem</returns>
+        public bool TryGetItemActionWithItem(out ItemActionType itemActionType, out EntityUid item)
+        {
+            itemActionType = _itemActionType;
+            item = _item;
+            return Assignment == Assignment.ItemActionWithItem;
+        }
+
+        public static ActionAssignment For(ActionType actionType)
+        {
+            return new(Assignment.Action, actionType, default, default);
+        }
+
+        public static ActionAssignment For(ItemActionType actionType)
+        {
+            return new(Assignment.ItemActionWithoutItem, default, actionType, default);
+        }
+
+        public static ActionAssignment For(ItemActionType actionType, EntityUid item)
+        {
+            return new(Assignment.ItemActionWithItem, default, actionType, item);
+        }
+
+        public bool Equals(ActionAssignment other)
+        {
+            return _actionType == other._actionType && _itemActionType == other._itemActionType && Equals(_item, other._item);
+        }
+
+        public override bool Equals(object obj)
+        {
+            return obj is ActionAssignment other && Equals(other);
+        }
+
+        public override int GetHashCode()
+        {
+            return HashCode.Combine(_actionType, _itemActionType, _item);
+        }
+
+        public override string ToString()
+        {
+            return $"{nameof(_actionType)}: {_actionType}, {nameof(_itemActionType)}: {_itemActionType}, {nameof(_item)}: {_item}, {nameof(Assignment)}: {Assignment}";
+        }
+    }
+
+    public enum Assignment : byte
+    {
+        Action,
+        ItemActionWithoutItem,
+        ItemActionWithItem
+    }
+}

Content.Client/GameObjects/Components/Mobs/Actions/ActionAssignments.cs

@@ -0,0 +1,304 @@
+using System.Collections.Generic;
+using System.Linq;
+using Content.Shared.Actions;
+using Content.Shared.GameObjects.Components.Mobs;
+using Robust.Shared.GameObjects;
+
+namespace Content.Client.GameObjects.Components.Mobs.Actions
+{
+    /// <summary>
+    /// Tracks and manages the hotbar assignments for actions.
+    /// </summary>
+    public class ActionAssignments
+    {
+        // the slots and assignments fields hold client's assignments (what action goes in what slot),
+        // which are completely client side and independent of what actions they've actually been granted and
+        // what item the action is actually for.
+
+        /// <summary>
+        /// x = hotbar number, y = slot of that hotbar (index 0 corresponds to the one labeled "1",
+        /// index 9 corresponds to the one labeled "0"). Essentially the inverse of _assignments.
+        /// </summary>
+        private readonly ActionAssignment?[,] _slots;
+
+        /// <summary>
+        /// Hotbar and slot assignment for each action type (slot index 0 corresponds to the one labeled "1",
+        /// slot index 9 corresponds to the one labeled "0"). The key corresponds to an index in the _slots array.
+        /// The value is a list because actions can be assigned to multiple slots. Even if an action type has not been granted,
+        /// it can still be assigned to a slot. Essentially the inverse of _slots.
+        /// There will be no entry if there is no assignment (no empty lists in this dict)
+        /// </summary>
+        private readonly Dictionary<ActionAssignment, List<(byte Hotbar, byte Slot)>> _assignments;
+
+        /// <summary>
+        /// Actions which have been manually cleared by the user, thus should not
+        /// auto-populate.
+        /// </summary>
+        private readonly HashSet<ActionType> _preventAutoPopulate = new();
+        private readonly Dictionary<EntityUid, HashSet<ItemActionType>> _preventAutoPopulateItem = new();
+
+        private readonly byte _numHotbars;
+        private readonly byte _numSlots;
+
+        public ActionAssignments(byte numHotbars, byte numSlots)
+        {
+            _numHotbars = numHotbars;
+            _numSlots = numSlots;
+            _assignments = new Dictionary<ActionAssignment, List<(byte Hotbar, byte Slot)>>();
+            _slots = new ActionAssignment?[numHotbars,numSlots];
+        }
+
+        /// <summary>
+        /// Updates the assignments based on the current states of all the actions.
+        /// Newly-granted actions or item actions which don't have an assignment will be assigned a slot
+        /// automatically (unless they've been manually cleared). Item-based actions
+        /// which no longer have an associated state will be decoupled from their item.
+        /// </summary>
+        public void Reconcile(byte currentHotbar, IReadOnlyDictionary<ActionType, ActionState> actionStates,
+            IReadOnlyDictionary<EntityUid,Dictionary<ItemActionType, ActionState>> itemActionStates)
+        {
+            // if we've been granted any actions which have no assignment to any hotbar, we must auto-populate them
+            // into the hotbar so the user knows about them.
+            // We fill their current hotbar first, rolling over to the next open slot on the next hotbar.
+            foreach (var actionState in actionStates)
+            {
+                var assignment = ActionAssignment.For(actionState.Key);
+                if (actionState.Value.Enabled && !_assignments.ContainsKey(assignment))
+                {
+                    AutoPopulate(assignment, currentHotbar, false);
+                }
+            }
+
+
+
+            foreach (var (item, itemStates) in itemActionStates)
+            {
+                foreach (var itemActionState in itemStates)
+                {
+                    // unlike regular actions, we DO actually show user their new item action even when it's disabled.
+                    // this allows them to instantly see when an action may be possible that is provided by an item but
+                    // something is preventing it
+                    // Note that we are checking if there is an explicit assignment for this item action + item,
+                    // we will determine during auto-population if we should tie the item to an existing "item action only"
+                    // assignment
+                    var assignment = ActionAssignment.For(itemActionState.Key, item);
+                    if (!_assignments.ContainsKey(assignment))
+                    {
+                        AutoPopulate(assignment, currentHotbar, false);
+                    }
+                }
+            }
+
+            // We need to figure out which current item action assignments we had
+            // which once had an associated item but have been revoked (based on our newly provided action states)
+            // so we can dissociate them from the item. If the provided action states do not
+            // have a state for this action type + item, we can assume that the action has been revoked for that item.
+            var assignmentsWithoutItem = new List<KeyValuePair<ActionAssignment,List<(byte Hotbar, byte Slot)>>>();
+            foreach (var assignmentEntry in _assignments)
+            {
+                if (!assignmentEntry.Key.TryGetItemActionWithItem(out var actionType, out var item)) continue;
+
+                // we have this assignment currently tied to an item,
+                // check if it no longer has an associated item in our dict of states
+                if (itemActionStates.TryGetValue(item, out var states))
+                {
+                    if (states.ContainsKey(actionType))
+                    {
+                        // we have a state for this item + action type so we won't
+                        // remove the item from the assignment
+                        continue;
+                    }
+                }
+                assignmentsWithoutItem.Add(assignmentEntry);
+            }
+            // reassign without the item for each assignment we found that no longer has an associated item
+            foreach (var (assignment, slots) in assignmentsWithoutItem)
+            {
+                foreach (var (hotbar, slot) in slots)
+                {
+                    if (!assignment.TryGetItemActionWithItem(out var actionType, out _)) continue;
+                    AssignSlot(hotbar, slot,
+                        ActionAssignment.For(actionType));
+                }
+            }
+
+            // Additionally, we must find items which have no action states at all in our newly provided states so
+            // we can assume their item was unequipped and reset them to allow auto-population.
+            var itemsWithoutState = _preventAutoPopulateItem.Keys.Where(item => !itemActionStates.ContainsKey(item));
+            foreach (var toRemove in itemsWithoutState)
+            {
+                _preventAutoPopulateItem.Remove(toRemove);
+            }
+        }
+
+        /// <summary>
+        /// Assigns the indicated hotbar slot to the specified action type.
+        /// </summary>
+        /// <param name="hotbar">hotbar whose slot is being assigned</param>
+        /// <param name="slot">slot of the hotbar to assign to (0 = the slot labeled 1, 9 = the slot labeled 0)</param>
+        /// <param name="actionType">action to assign to the slot</param>
+        public void AssignSlot(byte hotbar, byte slot, ActionAssignment actionType)
+        {
+            ClearSlot(hotbar, slot, false);
+            _slots[hotbar, slot] = actionType;
+            if (_assignments.TryGetValue(actionType, out var slotList))
+            {
+                slotList.Add((hotbar, slot));
+            }
+            else
+            {
+                var newList = new List<(byte Hotbar, byte Slot)> {(hotbar, slot)};
+                _assignments[actionType] = newList;
+            }
+        }
+
+        /// <summary>
+        /// Clear the assignment from the indicated slot.
+        /// </summary>
+        /// <param name="hotbar">hotbar whose slot is being cleared</param>
+        /// <param name="slot">slot of the hotbar to clear (0 = the slot labeled 1, 9 = the slot labeled 0)</param>
+        /// <param name="preventAutoPopulate">if true, the action assigned to this slot
+        /// will be prevented from being auto-populated in the future when it is newly granted.
+        /// Item actions will automatically be allowed to auto populate again
+        /// when their associated item are unequipped. This ensures that items that are newly
+        /// picked up will always present their actions to the user even if they had earlier been cleared.
+        /// </param>
+        public void ClearSlot(byte hotbar, byte slot, bool preventAutoPopulate)
+        {
+            // remove this particular assignment from our data structures
+            // (keeping in mind something can be assigned multiple slots)
+            var currentAction = _slots[hotbar, slot];
+            if (!currentAction.HasValue) return;
+            if (preventAutoPopulate)
+            {
+                var assignment = currentAction.Value;
+
+                if (assignment.TryGetAction(out var actionType))
+                {
+                    _preventAutoPopulate.Add(actionType);
+                }
+                else if (assignment.TryGetItemActionWithItem(out var itemActionType, out var item))
+                {
+                    if (!_preventAutoPopulateItem.TryGetValue(item, out var actionTypes))
+                    {
+                        actionTypes = new HashSet<ItemActionType>();
+                        _preventAutoPopulateItem[item] = actionTypes;
+                    }
+
+                    actionTypes.Add(itemActionType);
+                }
+            }
+            var assignmentList = _assignments[currentAction.Value];
+            assignmentList = assignmentList.Where(a => a.Hotbar != hotbar || a.Slot != slot).ToList();
+            if (assignmentList.Count == 0)
+            {
+                _assignments.Remove(currentAction.Value);
+            }
+            else
+            {
+                _assignments[currentAction.Value] = assignmentList;
+            }
+            _slots[hotbar, slot] = null;
+        }
+
+        /// <summary>
+        /// Finds the next open slot the action can go in and assigns it there,
+        /// starting from the currently selected hotbar.
+        /// Does not update any UI elements, only updates the assignment data structures.
+        /// </summary>
+        /// <param name="force">if true, will force the assignment to occur
+        /// regardless of whether this assignment has been prevented from auto population
+        /// via ClearSlot's preventAutoPopulate parameter. If false, will have no effect
+        /// if this assignment has been prevented from auto population.</param>
+        public void AutoPopulate(ActionAssignment toAssign, byte currentHotbar, bool force = true)
+        {
+            if (ShouldPreventAutoPopulate(toAssign, force)) return;
+            // if the assignment to make is an item action with an associated item,
+            // then first look for currently assigned item actions without an item, to replace with this
+            // assignment
+            if (toAssign.TryGetItemActionWithItem(out var actionType, out var _))
+            {
+                if (_assignments.TryGetValue(ActionAssignment.For(actionType),
+                    out var possibilities))
+                {
+                    // use the closest assignment to current hotbar
+                    byte hotbar = 0;
+                    byte slot = 0;
+                    var minCost = int.MaxValue;
+                    foreach (var possibility in possibilities)
+                    {
+                        var cost = possibility.Slot + _numSlots * (currentHotbar >= possibility.Hotbar
+                            ? currentHotbar - possibility.Hotbar
+                            : (_numHotbars - currentHotbar) + possibility.Hotbar);
+                        if (cost < minCost)
+                        {
+                            hotbar = possibility.Hotbar;
+                            slot = possibility.Slot;
+                            minCost = cost;
+                        }
+                    }
+
+                    if (minCost != int.MaxValue)
+                    {
+                        AssignSlot(hotbar, slot, toAssign);
+                        return;
+                    }
+                }
+            }
+
+            for (byte hotbarOffset = 0; hotbarOffset < _numHotbars; hotbarOffset++)
+            {
+                for (byte slot = 0; slot < _numSlots; slot++)
+                {
+                    var hotbar = (byte) ((currentHotbar + hotbarOffset) % _numHotbars);
+                    var slotAssignment = _slots[hotbar, slot];
+                    if (slotAssignment.HasValue)
+                    {
+                        // if the assignment in this slot is an item action without an associated item,
+                        // then tie it to the current item if we are trying to auto populate an item action.
+                        if (toAssign.Assignment == Assignment.ItemActionWithItem &&
+                            slotAssignment.Value.Assignment == Assignment.ItemActionWithoutItem)
+                        {
+                            AssignSlot(hotbar, slot, toAssign);
+                            return;
+                        }
+                        continue;
+                    }
+                    // slot's empty, assign
+                    AssignSlot(hotbar, slot, toAssign);
+                    return;
+                }
+            }
+            // there was no empty slot
+        }
+
+        private bool ShouldPreventAutoPopulate(ActionAssignment assignment, bool force)
+        {
+            if (force) return false;
+
+            if (assignment.TryGetAction(out var actionType))
+            {
+                return _preventAutoPopulate.Contains(actionType);
+            }
+
+            if (assignment.TryGetItemActionWithItem(out var itemActionType, out var item))
+            {
+                return _preventAutoPopulateItem.TryGetValue(item,
+                    out var itemActionTypes) && itemActionTypes.Contains(itemActionType);
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Gets the assignment to the indicated slot if there is one.
+        /// </summary>
+        public ActionAssignment? this[in byte hotbar, in byte slot] => _slots[hotbar, slot];
+
+        /// <returns>true if we have the assignment assigned to some slot</returns>
+        public bool HasAssignment(ActionAssignment assignment)
+        {
+            return _assignments.ContainsKey(assignment);
+        }
+    }
+}

Content.Client/GameObjects/Components/Mobs/ClientActionsComponent.cs

@@ -0,0 +1,273 @@
+#nullable enable
+using System.Collections.Generic;
+using Content.Client.GameObjects.Components.HUD.Inventory;
+using Content.Client.GameObjects.Components.Items;
+using Content.Client.GameObjects.Components.Mobs.Actions;
+using Content.Client.UserInterface;
+using Content.Client.UserInterface.Controls;
+using Content.Shared.Actions;
+using Content.Shared.GameObjects.Components.Mobs;
+using Robust.Client.GameObjects;
+using Robust.Client.GameObjects.EntitySystems;
+using Robust.Client.Interfaces.UserInterface;
+using Robust.Client.Player;
+using Robust.Shared.GameObjects;
+using Robust.Shared.GameObjects.ComponentDependencies;
+using Robust.Shared.GameObjects.Systems;
+using Robust.Shared.Input.Binding;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Client.GameObjects.Components.Mobs
+{
+    /// <inheritdoc/>
+    [RegisterComponent]
+    [ComponentReference(typeof(SharedActionsComponent))]
+    public sealed class ClientActionsComponent : SharedActionsComponent
+    {
+        public const byte Hotbars = 10;
+        public const byte Slots = 10;
+
+        [Dependency] private readonly IPlayerManager _playerManager = default!;
+
+        [ComponentDependency] private readonly HandsComponent? _handsComponent = null;
+        [ComponentDependency] private readonly ClientInventoryComponent? _inventoryComponent = null;
+
+        private ActionsUI? _ui;
+        private readonly List<ItemSlotButton> _highlightingItemSlots = new();
+
+        /// <summary>
+        /// Current assignments for all hotbars / slots for this entity.
+        /// </summary>
+        public ActionAssignments Assignments { get; } = new(Hotbars, Slots);
+
+        /// <summary>
+        /// Allows calculating if we need to act due to this component being controlled by the current mob
+        /// </summary>
+        [ViewVariables]
+        private bool CurrentlyControlled => _playerManager.LocalPlayer != null && _playerManager.LocalPlayer.ControlledEntity == Owner;
+
+
+        protected override void Shutdown()
+        {
+            base.Shutdown();
+            PlayerDetached();
+        }
+
+        public override void HandleMessage(ComponentMessage message, IComponent? component)
+        {
+            base.HandleMessage(message, component);
+            switch (message)
+            {
+                case PlayerAttachedMsg _:
+                    PlayerAttached();
+                    break;
+                case PlayerDetachedMsg _:
+                    PlayerDetached();
+                    break;
+            }
+        }
+
+        public override void HandleComponentState(ComponentState? curState, ComponentState? nextState)
+        {
+            base.HandleComponentState(curState, nextState);
+
+            if (curState is not ActionComponentState)
+            {
+                return;
+            }
+
+            UpdateUI();
+        }
+
+        private void PlayerAttached()
+        {
+            if (!CurrentlyControlled || _ui != null)
+            {
+                return;
+            }
+
+            _ui = new ActionsUI(this);
+            IoCManager.Resolve<IUserInterfaceManager>().StateRoot.AddChild(_ui);
+            UpdateUI();
+        }
+
+        private void PlayerDetached()
+        {
+            if (_ui == null) return;
+            IoCManager.Resolve<IUserInterfaceManager>().StateRoot.RemoveChild(_ui);
+            _ui = null;
+        }
+
+        public void HandleHotbarKeybind(byte slot, in PointerInputCmdHandler.PointerInputCmdArgs args)
+        {
+            _ui?.HandleHotbarKeybind(slot, args);
+        }
+
+        /// <summary>
+        /// Updates the displayed hotbar (and menu) based on current state of actions.
+        /// </summary>
+        private void UpdateUI()
+        {
+            if (!CurrentlyControlled || _ui == null)
+            {
+                return;
+            }
+
+            Assignments.Reconcile(_ui.SelectedHotbar, ActionStates(), ItemActionStates());
+
+            _ui.UpdateUI();
+        }
+
+        public void AttemptAction(ActionSlot slot)
+        {
+
+            var attempt = slot.ActionAttempt();
+            if (attempt == null) return;
+
+            switch (attempt.Action.BehaviorType)
+            {
+                case BehaviorType.Instant:
+                    // for instant actions, we immediately tell the server we're doing it
+                    SendNetworkMessage(attempt.PerformInstantActionMessage());
+                    break;
+                case BehaviorType.Toggle:
+                    // for toggle actions, we immediately tell the server we're toggling it.
+                    if (attempt.TryGetActionState(this, out var actionState))
+                    {
+                        // TODO: At the moment we always predict that the toggle will work clientside,
+                        // even if it sometimes may not (it will be reset by the server if wrong).
+                        attempt.ToggleAction(this, !actionState.ToggledOn);
+                        slot.ToggledOn = !actionState.ToggledOn;
+                        SendNetworkMessage(attempt.PerformToggleActionMessage(!actionState.ToggledOn));
+                    }
+                    else
+                    {
+                        Logger.ErrorS("action", "attempted to toggle action {0} which has" +
+                                                  " unknown state", attempt);
+                    }
+
+                    break;
+                case BehaviorType.TargetPoint:
+                case BehaviorType.TargetEntity:
+                    // for target actions, we go into "select target" mode, we don't
+                    // message the server until we actually pick our target.
+
+                    // if we're clicking the same thing we're already targeting for, then we simply cancel
+                    // targeting
+                    _ui?.ToggleTargeting(slot);
+                    break;
+                case BehaviorType.None:
+                    break;
+                default:
+                    Logger.ErrorS("action", "unhandled action press for action {0}",
+                        attempt);
+                    break;
+            }
+        }
+
+        /// <summary>
+        /// Handles clicks when selecting the target for an action. Only has an effect when currently
+        /// selecting a target.
+        /// </summary>
+        public bool TargetingOnUse(in PointerInputCmdHandler.PointerInputCmdArgs args)
+        {
+            // not currently predicted
+            if (EntitySystem.Get<InputSystem>().Predicted) return false;
+
+            // only do something for actual target-based actions
+            if (_ui?.SelectingTargetFor?.Action == null ||
+                (_ui.SelectingTargetFor.Action.BehaviorType != BehaviorType.TargetEntity &&
+                 _ui.SelectingTargetFor.Action.BehaviorType != BehaviorType.TargetPoint)) return false;
+
+            var attempt = _ui.SelectingTargetFor.ActionAttempt();
+            if (attempt == null)
+            {
+                _ui.StopTargeting();
+                return false;
+            }
+
+            switch (_ui.SelectingTargetFor.Action.BehaviorType)
+            {
+                case BehaviorType.TargetPoint:
+                {
+                    // send our action to the server, we chose our target
+                    SendNetworkMessage(attempt.PerformTargetPointActionMessage(args));
+                    if (!attempt.Action.Repeat)
+                    {
+                        _ui.StopTargeting();
+                    }
+                    return true;
+                }
+                // target the currently hovered entity, if there is one
+                case BehaviorType.TargetEntity when args.EntityUid != EntityUid.Invalid:
+                {
+                    // send our action to the server, we chose our target
+                    SendNetworkMessage(attempt.PerformTargetEntityActionMessage(args));
+                    if (!attempt.Action.Repeat)
+                    {
+                        _ui.StopTargeting();
+                    }
+                    return true;
+                }
+                default:
+                    _ui.StopTargeting();
+                    return false;
+            }
+        }
+
+        protected override void AfterActionChanged()
+        {
+            UpdateUI();
+        }
+
+        /// <summary>
+        /// Highlights the item slot (inventory or hand) that contains this item
+        /// </summary>
+        /// <param name="item"></param>
+        public void HighlightItemSlot(IEntity item)
+        {
+            StopHighlightingItemSlots();
+
+            // figure out if it's in hand or inventory and highlight it
+            foreach (var hand in _handsComponent!.Hands)
+            {
+                if (hand.Entity != item || hand.Button == null) continue;
+                _highlightingItemSlots.Add(hand.Button);
+                hand.Button.Highlight(true);
+                return;
+            }
+
+            foreach (var (slot, slotItem) in _inventoryComponent!.AllSlots)
+            {
+                if (slotItem != item) continue;
+                foreach (var itemSlotButton in
+                    _inventoryComponent.InterfaceController.GetItemSlotButtons(slot))
+                {
+                    _highlightingItemSlots.Add(itemSlotButton);
+                    itemSlotButton.Highlight(true);
+                }
+                return;
+            }
+        }
+
+        /// <summary>
+        /// Stops highlighting any item slots we are currently highlighting.
+        /// </summary>
+        public void StopHighlightingItemSlots()
+        {
+            foreach (var itemSlot in _highlightingItemSlots)
+            {
+                itemSlot.Highlight(false);
+            }
+            _highlightingItemSlots.Clear();
+        }
+
+        public void ToggleActionsMenu()
+        {
+            _ui?.ToggleActionsMenu();
+        }
+    }
+}

Content.Client/GameObjects/Components/Mobs/ClientAlertsComponent.cs

@@ -1,25 +1,20 @@
-using System;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Linq;
 using Content.Client.UserInterface;
-using Content.Client.UserInterface.Stylesheets;
+using Content.Client.UserInterface.Controls;
 using Content.Shared.Alert;
 using Content.Shared.GameObjects.Components.Mobs;
 using Robust.Client.GameObjects;
-using Robust.Client.Interfaces.Graphics;
 using Robust.Client.Interfaces.ResourceManagement;
 using Robust.Client.Interfaces.UserInterface;
 using Robust.Client.Player;
-using Robust.Client.UserInterface;
 using Robust.Client.UserInterface.Controls;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Input;
 using Robust.Shared.Interfaces.GameObjects;
-using Robust.Shared.Interfaces.Timing;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Prototypes;
-using Robust.Shared.Utility;
 using Robust.Shared.ViewVariables;
 
 namespace Content.Client.GameObjects.Components.Mobs
@@ -29,19 +24,11 @@ namespace Content.Client.GameObjects.Components.Mobs
     [ComponentReference(typeof(SharedAlertsComponent))]
     public sealed class ClientAlertsComponent : SharedAlertsComponent
     {
-        private static readonly float TooltipTextMaxWidth = 265;
-
         [Dependency] private readonly IPlayerManager _playerManager = default!;
         [Dependency] private readonly IResourceCache _resourceCache = default!;
-        [Dependency] private readonly IGameTiming _gameTiming = default!;
 
         private AlertsUI _ui;
-        private PanelContainer _tooltip;
-        private RichTextLabel _stateName;
-        private RichTextLabel _stateDescription;
-        private RichTextLabel _stateCooldown;
         private AlertOrderPrototype _alertOrder;
-        private bool _tooltipReady;
 
         [ViewVariables]
         private readonly Dictionary<AlertKey, AlertControl> _alertControls
@@ -49,7 +36,6 @@ namespace Content.Client.GameObjects.Components.Mobs
 
         /// <summary>
         /// Allows calculating if we need to act due to this component being controlled by the current mob
-        /// TODO: should be revisited after space-wizards/RobustToolbox#1255
         /// </summary>
         [ViewVariables]
         private bool CurrentlyControlled => _playerManager.LocalPlayer != null && _playerManager.LocalPlayer.ControlledEntity == Owner;
@@ -78,14 +64,11 @@ namespace Content.Client.GameObjects.Components.Mobs
         {
             base.HandleComponentState(curState, nextState);
 
-            if (curState is not AlertsComponentState state)
+            if (curState is not AlertsComponentState)
             {
                 return;
             }
 
-            // update the dict of states based on the array we got in the message
-            SetAlerts(state.Alerts);
-
             UpdateAlertsControls();
         }
 
@@ -102,48 +85,24 @@ namespace Content.Client.GameObjects.Components.Mobs
                 Logger.ErrorS("alert", "no alertOrder prototype found, alerts will be in random order");
             }
 
-            _ui = new AlertsUI(IoCManager.Resolve<IClyde>());
-            var uiManager = IoCManager.Resolve<IUserInterfaceManager>();
-            uiManager.StateRoot.AddChild(_ui);
-
-            _tooltip = new PanelContainer
-            {
-                Visible = false,
-                StyleClasses = { StyleNano.StyleClassTooltipPanel }
-            };
-            var tooltipVBox = new VBoxContainer
-            {
-                RectClipContent = true
-            };
-            _tooltip.AddChild(tooltipVBox);
-            _stateName = new RichTextLabel
-            {
-                MaxWidth = TooltipTextMaxWidth,
-                StyleClasses = { StyleNano.StyleClassTooltipAlertTitle }
-            };
-            tooltipVBox.AddChild(_stateName);
-            _stateDescription = new RichTextLabel
-            {
-                MaxWidth = TooltipTextMaxWidth,
-                StyleClasses = { StyleNano.StyleClassTooltipAlertDescription }
-            };
-            tooltipVBox.AddChild(_stateDescription);
-            _stateCooldown = new RichTextLabel
-            {
-                MaxWidth = TooltipTextMaxWidth,
-                StyleClasses = { StyleNano.StyleClassTooltipAlertCooldown }
-            };
-            tooltipVBox.AddChild(_stateCooldown);
-
-            uiManager.PopupRoot.AddChild(_tooltip);
+            _ui = new AlertsUI();
+            IoCManager.Resolve<IUserInterfaceManager>().StateRoot.AddChild(_ui);
 
             UpdateAlertsControls();
         }
 
         private void PlayerDetached()
         {
-            _ui?.Dispose();
+            foreach (var alertControl in _alertControls.Values)
+            {
+                alertControl.OnPressed -= AlertControlOnPressed;
+            }
+
+            if (_ui != null)
+            {
+                IoCManager.Resolve<IUserInterfaceManager>().StateRoot.RemoveChild(_ui);
                 _ui = null;
+            }
             _alertControls.Clear();
         }
 
@@ -168,39 +127,49 @@ namespace Content.Client.GameObjects.Components.Mobs
                     toRemove.Add(existingKey);
                 }
             }
-
             foreach (var alertKeyToRemove in toRemove)
             {
-                // remove and dispose the control
                 _alertControls.Remove(alertKeyToRemove, out var control);
-                control?.Dispose();
+                if (control == null) return;
+                _ui.Grid.Children.Remove(control);
             }
 
             // now we know that alertControls contains alerts that should still exist but
             // may need to updated,
             // also there may be some new alerts we need to show.
             // further, we need to ensure they are ordered w.r.t their configured order
-            foreach (var alertStatus in EnumerateAlertStates())
+            foreach (var (alertKey, alertState) in EnumerateAlertStates())
             {
-                if (!AlertManager.TryDecode(alertStatus.AlertEncoded, out var newAlert))
+                if (!alertKey.AlertType.HasValue)
                 {
-                    Logger.ErrorS("alert", "Unable to decode alert {0}", alertStatus.AlertEncoded);
+                    Logger.WarningS("alert", "found alertkey without alerttype," +
+                                             " alert keys should never be stored without an alerttype set: {0}", alertKey);
+                    continue;
+                }
+                var alertType = alertKey.AlertType.Value;
+                if (!AlertManager.TryGet(alertType, out var newAlert))
+                {
+                    Logger.ErrorS("alert", "Unrecognized alertType {0}", alertType);
                     continue;
                 }
 
                 if (_alertControls.TryGetValue(newAlert.AlertKey, out var existingAlertControl) &&
                     existingAlertControl.Alert.AlertType == newAlert.AlertType)
                 {
-                    // id is the same, simply update the existing control severity
-                    existingAlertControl.SetSeverity(alertStatus.Severity);
+                    // key is the same, simply update the existing control severity / cooldown
+                    existingAlertControl.SetSeverity(alertState.Severity);
+                    existingAlertControl.Cooldown = alertState.Cooldown;
                 }
                 else
                 {
-                    existingAlertControl?.Dispose();
+                    if (existingAlertControl != null)
+                    {
+                        _ui.Grid.Children.Remove(existingAlertControl);
+                    }
 
                     // this is a new alert + alert key or just a different alert with the same
                     // key, create the control and add it in the appropriate order
-                    var newAlertControl = CreateAlertControl(newAlert, alertStatus);
+                    var newAlertControl = CreateAlertControl(newAlert, alertState);
                     if (_alertOrder != null)
                     {
                         var added = false;
@@ -233,14 +202,11 @@ namespace Content.Client.GameObjects.Components.Mobs
 
         private AlertControl CreateAlertControl(AlertPrototype alert, AlertState alertState)
         {
-
-            var alertControl = new AlertControl(alert, alertState.Severity, _resourceCache);
-            // show custom tooltip for the status control
-            alertControl.OnShowTooltip += AlertOnOnShowTooltip;
-            alertControl.OnHideTooltip += AlertOnOnHideTooltip;
-
+            var alertControl = new AlertControl(alert, alertState.Severity, _resourceCache)
+            {
+                Cooldown = alertState.Cooldown
+            };
             alertControl.OnPressed += AlertControlOnPressed;
-
             return alertControl;
         }
 
@@ -249,36 +215,6 @@ namespace Content.Client.GameObjects.Components.Mobs
             AlertPressed(args, args.Button as AlertControl);
         }
 
-        private void AlertOnOnHideTooltip(object sender, EventArgs e)
-        {
-            _tooltipReady = false;
-            _tooltip.Visible = false;
-        }
-
-        private void AlertOnOnShowTooltip(object sender, EventArgs e)
-        {
-            var alertControl = (AlertControl) sender;
-            _stateName.SetMessage(alertControl.Alert.Name);
-            _stateDescription.SetMessage(alertControl.Alert.Description);
-            // check for a cooldown
-            if (alertControl.TotalDuration != null && alertControl.TotalDuration > 0)
-            {
-                _stateCooldown.SetMessage(FormattedMessage.FromMarkup("[color=#776a6a]" +
-                                                                      alertControl.TotalDuration +
-                                                                      " sec cooldown[/color]"));
-                _stateCooldown.Visible = true;
-            }
-            else
-            {
-                _stateCooldown.Visible = false;
-            }
-            // TODO: Text display of cooldown
-            Tooltips.PositionTooltip(_tooltip);
-            // if we set it visible here the size of the previous tooltip will flicker for a frame,
-            // so instead we wait until FrameUpdate to make it visible
-            _tooltipReady = true;
-        }
-
         private void AlertPressed(BaseButton.ButtonEventArgs args, AlertControl alert)
         {
             if (args.Event.Function != EngineKeyFunctions.UIClick)
@@ -286,57 +222,17 @@ namespace Content.Client.GameObjects.Components.Mobs
                 return;
             }
 
-            if (AlertManager.TryEncode(alert.Alert, out var encoded))
-            {
-                SendNetworkMessage(new ClickAlertMessage(encoded));
-            }
-            else
-            {
-                Logger.ErrorS("alert", "unable to encode alert {0}", alert.Alert.AlertType);
+            SendNetworkMessage(new ClickAlertMessage(alert.Alert.AlertType));
         }
 
-        }
-
-        public void FrameUpdate(float frameTime)
+        protected override void AfterShowAlert()
         {
-            if (_tooltipReady)
-            {
-                _tooltipReady = false;
-                _tooltip.Visible = true;
-            }
-            foreach (var (alertKey, alertControl) in _alertControls)
-            {
-                // reconcile all alert controls with their current cooldowns
-                if (TryGetAlertState(alertKey, out var alertState))
-                {
-                    alertControl.UpdateCooldown(alertState.Cooldown, _gameTiming.CurTime);
-                }
-                else
-                {
-                    Logger.WarningS("alert", "coding error - no alert state for alert {0} " +
-                                             "even though we had an AlertControl for it, this" +
-                                             " should never happen", alertControl.Alert.AlertType);
-                }
-
-            }
+            UpdateAlertsControls();
         }
 
         protected override void AfterClearAlert()
         {
             UpdateAlertsControls();
         }
-
-        public override void OnRemove()
-        {
-            base.OnRemove();
-
-            foreach (var alertControl in _alertControls.Values)
-            {
-                alertControl.OnShowTooltip -= AlertOnOnShowTooltip;
-                alertControl.OnHideTooltip -= AlertOnOnHideTooltip;
-                alertControl.OnPressed -= AlertControlOnPressed;
-            }
-
-        }
     }
 }

Content.Client/GameObjects/EntitySystems/ActionsSystem.cs

@@ -0,0 +1,91 @@
+using Content.Client.GameObjects.Components.Mobs;
+using Content.Shared.Input;
+using JetBrains.Annotations;
+using Robust.Client.Player;
+using Robust.Shared.GameObjects.Systems;
+using Robust.Shared.Input;
+using Robust.Shared.Input.Binding;
+using Robust.Shared.IoC;
+
+namespace Content.Client.GameObjects.EntitySystems
+{
+    [UsedImplicitly]
+    public class ActionsSystem : EntitySystem
+    {
+        [Dependency] private readonly IPlayerManager _playerManager = default!;
+
+        public override void Initialize()
+        {
+            base.Initialize();
+
+            // set up hotkeys for hotbar
+            CommandBinds.Builder
+                .Bind(ContentKeyFunctions.OpenActionsMenu,
+                    InputCmdHandler.FromDelegate(_ => ToggleActionsMenu()))
+                .Bind(ContentKeyFunctions.Hotbar1,
+                    HandleHotbarKeybind(0))
+                .Bind(ContentKeyFunctions.Hotbar2,
+                    HandleHotbarKeybind(1))
+                .Bind(ContentKeyFunctions.Hotbar3,
+                    HandleHotbarKeybind(2))
+                .Bind(ContentKeyFunctions.Hotbar4,
+                    HandleHotbarKeybind(3))
+                .Bind(ContentKeyFunctions.Hotbar5,
+                    HandleHotbarKeybind(4))
+                .Bind(ContentKeyFunctions.Hotbar6,
+                    HandleHotbarKeybind(5))
+                .Bind(ContentKeyFunctions.Hotbar7,
+                    HandleHotbarKeybind(6))
+                .Bind(ContentKeyFunctions.Hotbar8,
+                    HandleHotbarKeybind(7))
+                .Bind(ContentKeyFunctions.Hotbar9,
+                    HandleHotbarKeybind(8))
+                .Bind(ContentKeyFunctions.Hotbar0,
+                    HandleHotbarKeybind(9))
+                // when selecting a target, we intercept clicks in the game world, treating them as our target selection. We want to
+                // take priority before any other systems handle the click.
+                .BindBefore(EngineKeyFunctions.Use, new PointerInputCmdHandler(TargetingOnUse),
+                    typeof(ConstructionSystem), typeof(DragDropSystem))
+                .Register<ActionsSystem>();
+        }
+
+        public override void Shutdown()
+        {
+            base.Shutdown();
+            CommandBinds.Unregister<ActionsSystem>();
+        }
+
+        private PointerInputCmdHandler HandleHotbarKeybind(byte slot)
+        {
+            // delegate to the ActionsUI, simulating a click on it
+            return new((in PointerInputCmdHandler.PointerInputCmdArgs args) =>
+                {
+                    var playerEntity = _playerManager.LocalPlayer.ControlledEntity;
+                    if (playerEntity == null ||
+                        !playerEntity.TryGetComponent<ClientActionsComponent>( out var actionsComponent)) return false;
+
+                    actionsComponent.HandleHotbarKeybind(slot, args);
+                    return true;
+                },
+                false);
+        }
+
+        private bool TargetingOnUse(in PointerInputCmdHandler.PointerInputCmdArgs args)
+        {
+            var playerEntity = _playerManager.LocalPlayer.ControlledEntity;
+            if (playerEntity == null ||
+                !playerEntity.TryGetComponent<ClientActionsComponent>( out var actionsComponent)) return false;
+
+            return actionsComponent.TargetingOnUse(args);
+        }
+
+        private void ToggleActionsMenu()
+        {
+            var playerEntity = _playerManager.LocalPlayer.ControlledEntity;
+            if (playerEntity == null ||
+                !playerEntity.TryGetComponent<ClientActionsComponent>( out var actionsComponent)) return;
+
+            actionsComponent.ToggleActionsMenu();
+        }
+    }
+}

Content.Client/GameObjects/EntitySystems/AlertsSystem.cs

@@ -1,27 +0,0 @@
-using Content.Client.GameObjects.Components.Mobs;
-using JetBrains.Annotations;
-using Robust.Shared.GameObjects.Systems;
-using Robust.Shared.Interfaces.Timing;
-using Robust.Shared.IoC;
-
-namespace Content.Client.GameObjects.EntitySystems
-{
-    [UsedImplicitly]
-    public class AlertsSystem : EntitySystem
-    {
-        [Dependency] private readonly IGameTiming _gameTiming = default!;
-
-        public override void FrameUpdate(float frameTime)
-        {
-            base.FrameUpdate(frameTime);
-
-            if (!_gameTiming.IsFirstTimePredicted)
-                return;
-
-            foreach (var clientAlertsComponent in EntityManager.ComponentManager.EntityQuery<ClientAlertsComponent>())
-            {
-                clientAlertsComponent.FrameUpdate(frameTime);
-            }
-        }
-    }
-}

Content.Client/GameObjects/EntitySystems/DragDropSystem.cs

@@ -1,6 +1,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using Content.Client.State;
+using Content.Client.Utility;
 using Content.Shared.GameObjects;
 using Content.Shared.GameObjects.EntitySystemMessages;
 using Content.Shared.GameObjects.EntitySystems;
@@ -10,7 +11,6 @@ using Robust.Client.GameObjects;
 using Robust.Client.GameObjects.EntitySystems;
 using Robust.Client.Graphics.Shaders;
 using Robust.Client.Interfaces.Graphics.ClientEye;
-using Robust.Client.Interfaces.Input;
 using Robust.Client.Interfaces.State;
 using Robust.Shared.GameObjects.Systems;
 using Robust.Shared.Input;
@@ -18,7 +18,6 @@ using Robust.Shared.Input.Binding;
 using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
-using Robust.Shared.Maths;
 using Robust.Shared.Prototypes;
 
 namespace Content.Client.GameObjects.EntitySystems
@@ -30,12 +29,9 @@ namespace Content.Client.GameObjects.EntitySystems
     public class DragDropSystem : EntitySystem
     {
         [Dependency] private readonly IStateManager _stateManager = default!;
-        [Dependency] private readonly IInputManager _inputManager = default!;
         [Dependency] private readonly IEyeManager _eyeManager = default!;
         [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
 
-        // drag will be triggered when mouse leaves this deadzone around the click position.
-        private const float DragDeadzone = 2f;
         // how often to recheck possible targets (prevents calling expensive
         // check logic each update)
         private const float TargetRecheckInterval = 0.25f;
@@ -50,14 +46,10 @@ namespace Content.Client.GameObjects.EntitySystems
 
         // entity performing the drag action
         private IEntity _dragger;
-        private IEntity _draggedEntity;
         private readonly List<IDraggable> _draggables = new();
         private IEntity _dragShadow;
-        private DragState _state;
         // time since mouse down over the dragged entity
         private float _mouseDownTime;
-        // screen pos where the mouse down began
-        private Vector2 _mouseDownScreenPos;
         // how much time since last recheck of all possible targets
         private float _targetRecheckTime;
         // reserved initial mousedown event so we can replay it if no drag ends up being performed
@@ -66,6 +58,8 @@ namespace Content.Client.GameObjects.EntitySystems
         // can ignore any events sent to this system
         private bool _isReplaying;
 
+        private DragDropHelper<IEntity> _dragDropHelper;
+
         private ShaderInstance _dropTargetInRangeShader;
         private ShaderInstance _dropTargetOutOfRangeShader;
         private SharedInteractionSystem _interactionSystem;
@@ -73,20 +67,9 @@ namespace Content.Client.GameObjects.EntitySystems
 
         private readonly List<SpriteComponent> _highlightedSprites = new();
 
-        private enum DragState : byte
-        {
-            NotDragging,
-            // not dragging yet, waiting to see
-            // if they hold for long enough
-            MouseDown,
-            // currently dragging something
-            Dragging,
-        }
-
-
         public override void Initialize()
         {
-            _state = DragState.NotDragging;
+            _dragDropHelper = new DragDropHelper<IEntity>(OnBeginDrag, OnContinueDrag, OnEndDrag);
 
             _dropTargetInRangeShader = _prototypeManager.Index<ShaderPrototype>(ShaderDropTargetInRange).Instance();
             _dropTargetOutOfRangeShader = _prototypeManager.Index<ShaderPrototype>(ShaderDropTargetOutOfRange).Instance();
@@ -101,7 +84,7 @@ namespace Content.Client.GameObjects.EntitySystems
 
         public override void Shutdown()
         {
-            CancelDrag(false, null);
+            _dragDropHelper.EndDrag();
             CommandBinds.Unregister<DragDropSystem>();
             base.Shutdown();
         }
@@ -132,7 +115,7 @@ namespace Content.Client.GameObjects.EntitySystems
             var dragger = args.Session.AttachedEntity;
             // cancel any current dragging if there is one (shouldn't be because they would've had to have lifted
             // the mouse, canceling the drag, but just being cautious)
-            CancelDrag(false, null);
+            _dragDropHelper.EndDrag();
 
             // possibly initiating a drag
             // check if the clicked entity is draggable
@@ -150,19 +133,21 @@ namespace Content.Client.GameObjects.EntitySystems
                     var dragEventArgs = new StartDragDropEventArgs(args.Session.AttachedEntity, entity);
                     if (draggable.CanStartDrag(dragEventArgs))
                     {
-                        // wait to initiate a drag
-                        _dragger = dragger;
-                        _draggedEntity = entity;
                         _draggables.Add(draggable);
+                        canDrag = true;
+                    }
+                }
+
+                if (canDrag)
+                {
+                    // wait to initiate a drag
+                    _dragDropHelper.MouseDown(entity);
+                    _dragger = dragger;
                     _mouseDownTime = 0;
-                        _state = DragState.MouseDown;
-                        _mouseDownScreenPos = _inputManager.MouseScreenPosition;
                     // don't want anything else to process the click,
                     // but we will save the event so we can "re-play" it if this drag does
                     // not turn into an actual drag so the click can be handled normally
                     _savedMouseDown = args;
-                        canDrag = true;
-                    }
                 }
 
                 return canDrag;
@@ -171,75 +156,20 @@ namespace Content.Client.GameObjects.EntitySystems
             return false;
         }
 
-        private bool OnUseMouseUp(in PointerInputCmdHandler.PointerInputCmdArgs args)
-        {
-            if (_state == DragState.MouseDown)
-            {
-                // quick mouseup, definitely treat it as a normal click by
-                // replaying the original
-                CancelDrag(true, args.OriginalMessage);
-                return false;
-            }
-            if (_state != DragState.Dragging) return false;
 
-            // remaining CancelDrag calls will not replay the click because
-            // by this time we've determined the input was actually a drag attempt
-
-
-            // tell the server we are dropping if we are over a valid drop target in range.
-            // We don't use args.EntityUid here because drag interactions generally should
-            // work even if there's something "on top" of the drop target
-            if (!_interactionSystem.InRangeUnobstructed(_dragger,
-                args.Coordinates, ignoreInsideBlocker: true))
+        private bool OnBeginDrag()
         {
-                CancelDrag(false, null);
+            if (_dragDropHelper.Dragged == null || _dragDropHelper.Dragged.Deleted)
+            {
+                // something happened to the clicked entity or we moved the mouse off the target so
+                // we shouldn't replay the original click
                 return false;
             }
 
-            var entities = GameScreenBase.GetEntitiesUnderPosition(_stateManager, args.Coordinates);
-
-            foreach (var entity in entities)
+            if (_dragDropHelper.Dragged.TryGetComponent<SpriteComponent>(out var draggedSprite))
             {
-                // check if it's able to be dropped on by current dragged entity
-                var dropArgs = new DragDropEventArgs(_dragger, args.Coordinates, _draggedEntity, entity);
-
-                foreach (var draggable in _draggables)
-                {
-                    if (!draggable.CanDrop(dropArgs))
-                    {
-                        continue;
-                    }
-
-                    // tell the server about the drop attempt
-                    RaiseNetworkEvent(new DragDropMessage(args.Coordinates, _draggedEntity.Uid,
-                        entity.Uid));
-
-                    draggable.Drop(dropArgs);
-
-                    CancelDrag(false, null);
-                    return true;
-                }
-            }
-
-            CancelDrag(false, null);
-            return false;
-        }
-
-        private void StartDragging()
-        {
-            // this is checked elsewhere but adding this as a failsafe
-            if (_draggedEntity == null || _draggedEntity.Deleted)
-            {
-                Logger.Error("Programming error. Cannot initiate drag, no dragged entity or entity" +
-                               " was deleted.");
-                return;
-            }
-
-            if (_draggedEntity.TryGetComponent<SpriteComponent>(out var draggedSprite))
-            {
-                _state = DragState.Dragging;
                 // pop up drag shadow under mouse
-                var mousePos = _eyeManager.ScreenToMap(_inputManager.MouseScreenPosition);
+                var mousePos = _eyeManager.ScreenToMap(_dragDropHelper.MouseScreenPosition);
                 _dragShadow = EntityManager.SpawnEntity("dragshadow", mousePos);
                 var dragSprite = _dragShadow.GetComponent<SpriteComponent>();
                 dragSprite.CopyFrom(draggedSprite);
@@ -249,22 +179,132 @@ namespace Content.Client.GameObjects.EntitySystems
                 dragSprite.DrawDepth = (int) DrawDepth.Overlays;
                 if (dragSprite.Directional)
                 {
-                    _dragShadow.Transform.WorldRotation = _draggedEntity.Transform.WorldRotation;
+                    _dragShadow.Transform.WorldRotation = _dragDropHelper.Dragged.Transform.WorldRotation;
                 }
 
                 HighlightTargets();
+
+                // drag initiated
+                return true;
             }
-            else
-            {
+
             Logger.Warning("Unable to display drag shadow for {0} because it" +
-                               " has no sprite component.", _draggedEntity.Name);
+                           " has no sprite component.", _dragDropHelper.Dragged.Name);
+            return false;
         }
+
+        private bool OnContinueDrag(float frameTime)
+        {
+            if (_dragDropHelper.Dragged == null || _dragDropHelper.Dragged.Deleted)
+            {
+                return false;
+            }
+            // still in range of the thing we are dragging?
+            if (!_interactionSystem.InRangeUnobstructed(_dragger, _dragDropHelper.Dragged))
+            {
+                return false;
+            }
+
+            // keep dragged entity under mouse
+            var mousePos = _eyeManager.ScreenToMap(_dragDropHelper.MouseScreenPosition);
+            // TODO: would use MapPosition instead if it had a setter, but it has no setter.
+            // is that intentional, or should we add a setter for Transform.MapPosition?
+            _dragShadow.Transform.WorldPosition = mousePos.Position;
+
+            _targetRecheckTime += frameTime;
+            if (_targetRecheckTime > TargetRecheckInterval)
+            {
+                HighlightTargets();
+                _targetRecheckTime = 0;
+            }
+
+            return true;
+        }
+
+        private void OnEndDrag()
+        {
+            RemoveHighlights();
+            if (_dragShadow != null)
+            {
+                EntityManager.DeleteEntity(_dragShadow);
+            }
+
+            _dragShadow = null;
+            _draggables.Clear();
+            _dragger = null;
+            _mouseDownTime = 0;
+            _savedMouseDown = null;
+        }
+
+        private bool OnUseMouseUp(in PointerInputCmdHandler.PointerInputCmdArgs args)
+        {
+            if (!_dragDropHelper.IsDragging)
+            {
+                // haven't started the drag yet, quick mouseup, definitely treat it as a normal click by
+                // replaying the original cmd
+                if (_savedMouseDown.HasValue && _mouseDownTime < MaxMouseDownTimeForReplayingClick)
+                {
+                    var savedValue = _savedMouseDown.Value;
+                    _isReplaying = true;
+                    // adjust the timing info based on the current tick so it appears as if it happened now
+                    var replayMsg = savedValue.OriginalMessage;
+                    var adjustedInputMsg = new FullInputCmdMessage(args.OriginalMessage.Tick, args.OriginalMessage.SubTick,
+                        replayMsg.InputFunctionId, replayMsg.State, replayMsg.Coordinates, replayMsg.ScreenCoordinates, replayMsg.Uid);
+
+                    _inputSystem.HandleInputCommand(savedValue.Session, EngineKeyFunctions.Use,
+                        adjustedInputMsg, true);
+                    _isReplaying = false;
+                }
+                _dragDropHelper.EndDrag();
+                return false;
+            }
+
+            // now when ending the drag, we will not replay the click because
+            // by this time we've determined the input was actually a drag attempt
+
+            // tell the server we are dropping if we are over a valid drop target in range.
+            // We don't use args.EntityUid here because drag interactions generally should
+            // work even if there's something "on top" of the drop target
+            if (!_interactionSystem.InRangeUnobstructed(_dragger,
+                args.Coordinates, ignoreInsideBlocker: true))
+            {
+                _dragDropHelper.EndDrag();
+                return false;
+            }
+
+            var entities = GameScreenBase.GetEntitiesUnderPosition(_stateManager, args.Coordinates);
+
+            foreach (var entity in entities)
+            {
+                // check if it's able to be dropped on by current dragged entity
+                var dropArgs = new DragDropEventArgs(_dragger, args.Coordinates, _dragDropHelper.Dragged, entity);
+
+                foreach (var draggable in _draggables)
+                {
+                    if (!draggable.CanDrop(dropArgs))
+                    {
+                        continue;
+                    }
+
+                    // tell the server about the drop attempt
+                    RaiseNetworkEvent(new DragDropMessage(args.Coordinates, _dragDropHelper.Dragged.Uid,
+                        entity.Uid));
+
+                    draggable.Drop(dropArgs);
+
+                    _dragDropHelper.EndDrag();
+                    return true;
+                }
+            }
+
+            _dragDropHelper.EndDrag();
+            return false;
         }
 
         private void HighlightTargets()
         {
-            if (_state != DragState.Dragging || _draggedEntity == null ||
-                _draggedEntity.Deleted || _dragShadow == null || _dragShadow.Deleted)
+            if (_dragDropHelper.Dragged == null ||
+                _dragDropHelper.Dragged.Deleted || _dragShadow == null || _dragShadow.Deleted)
             {
                 Logger.Warning("Programming error. Can't highlight drag and drop targets, not currently " +
                                "dragging anything or dragged entity / shadow was deleted.");
@@ -289,7 +329,7 @@ namespace Content.Client.GameObjects.EntitySystems
                     if (inRangeSprite.Visible == false) continue;
 
                     // check if it's able to be dropped on by current dragged entity
-                    var canDropArgs = new CanDropEventArgs(_dragger,  _draggedEntity, pvsEntity);
+                    var canDropArgs = new CanDropEventArgs(_dragger,  _dragDropHelper.Dragged, pvsEntity);
                     var anyValidDraggable = _draggables.Any(draggable => draggable.CanDrop(canDropArgs));
 
                     if (anyValidDraggable)
@@ -314,95 +354,10 @@ namespace Content.Client.GameObjects.EntitySystems
             _highlightedSprites.Clear();
         }
 
-        /// <summary>
-        /// Cancels the drag, firing our saved drag event if instructed to do so and
-        /// we are within the threshold for replaying the click
-        /// (essentially reverting the drag attempt and allowing the original click
-        /// to proceed as if no drag was performed)
-        /// </summary>
-        /// <param name="cause">if fireSavedCmd is true, this should be passed with the value of
-        ///  the pointer cmd that caused the drag to be cancelled</param>
-        private void CancelDrag(bool fireSavedCmd, FullInputCmdMessage cause)
-        {
-            RemoveHighlights();
-            if (_dragShadow != null)
-            {
-                EntityManager.DeleteEntity(_dragShadow);
-            }
-
-            _dragShadow = null;
-            _draggedEntity = null;
-            _draggables.Clear();
-            _dragger = null;
-            _state = DragState.NotDragging;
-
-            _mouseDownTime = 0;
-
-            if (fireSavedCmd && _savedMouseDown.HasValue && _mouseDownTime < MaxMouseDownTimeForReplayingClick)
-            {
-                var savedValue = _savedMouseDown.Value;
-                _isReplaying = true;
-                // adjust the timing info based on the current tick so it appears as if it happened now
-                var replayMsg = savedValue.OriginalMessage;
-                var adjustedInputMsg = new FullInputCmdMessage(cause.Tick, cause.SubTick, replayMsg.InputFunctionId, replayMsg.State, replayMsg.Coordinates, replayMsg.ScreenCoordinates, replayMsg.Uid);
-
-                _inputSystem.HandleInputCommand(savedValue.Session, EngineKeyFunctions.Use,
-                    adjustedInputMsg, true);
-                _isReplaying = false;
-            }
-
-            _savedMouseDown = null;
-
-        }
-
         public override void Update(float frameTime)
         {
             base.Update(frameTime);
-            if (_state == DragState.MouseDown)
-            {
-                var screenPos = _inputManager.MouseScreenPosition;
-                if (_draggedEntity == null || _draggedEntity.Deleted)
-                {
-                    // something happened to the clicked entity or we moved the mouse off the target so
-                    // we shouldn't replay the original click
-                    CancelDrag(false, null);
-                    return;
-                }
-                else if ((_mouseDownScreenPos - screenPos).Length > DragDeadzone)
-                {
-                    // initiate actual drag
-                    StartDragging();
-                    _mouseDownTime = 0;
-                }
-            }
-            else if (_state == DragState.Dragging)
-            {
-                if (_draggedEntity == null || _draggedEntity.Deleted)
-                {
-                    CancelDrag(false, null);
-                    return;
-                }
-                // still in range of the thing we are dragging?
-                if (!_interactionSystem.InRangeUnobstructed(_dragger, _draggedEntity))
-                {
-                    CancelDrag(false, null);
-                    return;
-                }
-
-                // keep dragged entity under mouse
-                var mousePos = _eyeManager.ScreenToMap(_inputManager.MouseScreenPosition);
-                // TODO: would use MapPosition instead if it had a setter, but it has no setter.
-                // is that intentional, or should we add a setter for Transform.MapPosition?
-                _dragShadow.Transform.WorldPosition = mousePos.Position;
-
-                _targetRecheckTime += frameTime;
-                if (_targetRecheckTime > TargetRecheckInterval)
-                {
-                    HighlightTargets();
-                    _targetRecheckTime = 0;
-                }
-
-            }
+            _dragDropHelper.Update(frameTime);
         }
     }
 }

Content.Client/IgnoredComponents.cs

@@ -210,6 +210,8 @@
             "CrematoriumEntityStorage",
             "RandomArcade",
             "RandomSpriteState",
+            "DebugEquip",
+            "InnateActions",
             "ReagentGrinder",
             "Grindable",
             "Juiceable",

Content.Client/Input/ContentContexts.cs

@@ -46,6 +46,17 @@ namespace Content.Client.Input
             human.AddFunction(ContentKeyFunctions.Arcade1);
             human.AddFunction(ContentKeyFunctions.Arcade2);
             human.AddFunction(ContentKeyFunctions.Arcade3);
+            human.AddFunction(ContentKeyFunctions.OpenActionsMenu);
+            human.AddFunction(ContentKeyFunctions.Hotbar0);
+            human.AddFunction(ContentKeyFunctions.Hotbar1);
+            human.AddFunction(ContentKeyFunctions.Hotbar2);
+            human.AddFunction(ContentKeyFunctions.Hotbar3);
+            human.AddFunction(ContentKeyFunctions.Hotbar4);
+            human.AddFunction(ContentKeyFunctions.Hotbar5);
+            human.AddFunction(ContentKeyFunctions.Hotbar6);
+            human.AddFunction(ContentKeyFunctions.Hotbar7);
+            human.AddFunction(ContentKeyFunctions.Hotbar8);
+            human.AddFunction(ContentKeyFunctions.Hotbar9);
 
             var ghost = contexts.New("ghost", "common");
             ghost.AddFunction(EngineKeyFunctions.MoveUp);

Content.Client/UserInterface/ActionAlertTooltip.cs

@@ -0,0 +1,100 @@
+#nullable enable
+
+using System;
+using Content.Client.UserInterface.Stylesheets;
+using Content.Shared.Actions;
+using Robust.Client.UserInterface.Controls;
+using Robust.Shared.Interfaces.Timing;
+using Robust.Shared.IoC;
+using Robust.Shared.Timing;
+using Robust.Shared.Utility;
+
+namespace Content.Client.UserInterface
+{
+    /// <summary>
+    /// Tooltip for actions or alerts because they are very similar.
+    /// </summary>
+    public class ActionAlertTooltip : PanelContainer
+    {
+        private const float TooltipTextMaxWidth = 350;
+
+        private readonly RichTextLabel _cooldownLabel;
+        private readonly IGameTiming _gameTiming;
+
+        /// <summary>
+        /// Current cooldown displayed in this tooltip. Set to null to show no cooldown.
+        /// </summary>
+        public (TimeSpan Start, TimeSpan End)? Cooldown { get; set; }
+
+        public ActionAlertTooltip(FormattedMessage name, FormattedMessage? desc, string? requires = null)
+        {
+            _gameTiming = IoCManager.Resolve<IGameTiming>();
+
+            SetOnlyStyleClass(StyleNano.StyleClassTooltipPanel);
+
+            VBoxContainer vbox;
+            AddChild(vbox = new VBoxContainer {RectClipContent = true});
+            var nameLabel = new RichTextLabel
+            {
+                MaxWidth = TooltipTextMaxWidth,
+                StyleClasses = {StyleNano.StyleClassTooltipActionTitle}
+            };
+            nameLabel.SetMessage(name);
+            vbox.AddChild(nameLabel);
+
+            if (desc != null && !string.IsNullOrWhiteSpace(desc.ToString()))
+            {
+                var description = new RichTextLabel
+                {
+                    MaxWidth = TooltipTextMaxWidth,
+                    StyleClasses = {StyleNano.StyleClassTooltipActionDescription}
+                };
+                description.SetMessage(desc);
+                vbox.AddChild(description);
+            }
+
+            vbox.AddChild(_cooldownLabel = new RichTextLabel
+            {
+                MaxWidth = TooltipTextMaxWidth,
+                StyleClasses = {StyleNano.StyleClassTooltipActionCooldown},
+                Visible = false
+            });
+
+            if (!string.IsNullOrWhiteSpace(requires))
+            {
+                var requiresLabel = new RichTextLabel
+                {
+                    MaxWidth = TooltipTextMaxWidth,
+                    StyleClasses = {StyleNano.StyleClassTooltipActionRequirements}
+                };
+                requiresLabel.SetMessage(FormattedMessage.FromMarkup("[color=#635c5c]" +
+                                                                     requires +
+                                                                     "[/color]"));
+                vbox.AddChild(requiresLabel);
+            }
+        }
+
+        protected override void FrameUpdate(FrameEventArgs args)
+        {
+            base.FrameUpdate(args);
+            if (!Cooldown.HasValue)
+            {
+                _cooldownLabel.Visible = false;
+                return;
+            }
+
+            var timeLeft = Cooldown.Value.End - _gameTiming.CurTime;
+            if (timeLeft > TimeSpan.Zero)
+            {
+                var duration = Cooldown.Value.End - Cooldown.Value.Start;
+                _cooldownLabel.SetMessage(FormattedMessage.FromMarkup(
+                    $"[color=#a10505]{duration.Seconds} sec cooldown ({timeLeft.Seconds + 1} sec remaining)[/color]"));
+                _cooldownLabel.Visible = true;
+            }
+            else
+            {
+                _cooldownLabel.Visible = false;
+            }
+        }
+    }
+}

Content.Client/UserInterface/ActionMenu.cs

@@ -0,0 +1,499 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using System.Text.RegularExpressions;
+using Content.Client.GameObjects.Components.Mobs;
+using Content.Client.GameObjects.Components.Mobs.Actions;
+using Content.Client.UserInterface.Controls;
+using Content.Client.UserInterface.Stylesheets;
+using Content.Client.Utility;
+using Content.Shared.Actions;
+using Robust.Client.UserInterface.Controls;
+using Robust.Client.UserInterface.CustomControls;
+using Robust.Client.Utility;
+using Robust.Shared.Input;
+using Robust.Shared.IoC;
+using Robust.Shared.Localization;
+using Robust.Shared.Log;
+using Robust.Shared.Timing;
+
+namespace Content.Client.UserInterface
+{
+    /// <summary>
+    /// Action selection menu, allows filtering and searching over all possible
+    /// actions and populating those actions into the hotbar.
+    /// </summary>
+    public class ActionMenu : SS14Window
+    {
+        private const string ItemTag = "item";
+        private const string NotItemTag = "not item";
+        private const string InstantActionTag = "instant";
+        private const string ToggleActionTag = "toggle";
+        private const string TargetActionTag = "target";
+        private const string AllActionsTag = "all";
+        private const string GrantedActionsTag = "granted";
+        private const int MinSearchLength = 3;
+        private static readonly Regex NonAlphanumeric = new Regex(@"\W", RegexOptions.Compiled);
+        private static readonly Regex Whitespace = new Regex(@"\s+", RegexOptions.Compiled);
+        private static readonly BaseActionPrototype[] EmptyActionList = Array.Empty<BaseActionPrototype>();
+
+        // parallel list of actions currently selectable in itemList
+        private BaseActionPrototype[] _actionList;
+
+        private readonly ActionManager _actionManager;
+        private readonly ClientActionsComponent _actionsComponent;
+        private readonly ActionsUI _actionsUI;
+        private readonly LineEdit _searchBar;
+        private readonly MultiselectOptionButton<string> _filterButton;
+        private readonly Label _filterLabel;
+        private readonly Button _clearButton;
+        private readonly GridContainer _resultsGrid;
+        private readonly TextureRect _dragShadow;
+        private readonly DragDropHelper<ActionMenuItem> _dragDropHelper;
+
+
+        public ActionMenu(ClientActionsComponent actionsComponent, ActionsUI actionsUI)
+        {
+            _actionsComponent = actionsComponent;
+            _actionsUI = actionsUI;
+            _actionManager = IoCManager.Resolve<ActionManager>();
+            Title = Loc.GetString("Actions");
+            CustomMinimumSize = (300, 300);
+
+            Contents.AddChild(new VBoxContainer
+            {
+                Children =
+                {
+                    new HBoxContainer
+                    {
+                        Children =
+                        {
+                            (_searchBar = new LineEdit
+                            {
+                                StyleClasses = { StyleNano.StyleClassActionSearchBox },
+                                SizeFlagsHorizontal = SizeFlags.FillExpand,
+                                PlaceHolder = Loc.GetString("Search")
+                            }),
+                            (_filterButton = new MultiselectOptionButton<string>()
+                            {
+                                Label = Loc.GetString("Filter")
+                            }),
+                        }
+                    },
+                    (_clearButton = new Button
+                    {
+                        Text = Loc.GetString("Clear"),
+                    }),
+                    (_filterLabel = new Label()),
+                    new ScrollContainer
+                    {
+                        //TODO: needed? CustomMinimumSize = new Vector2(200.0f, 0.0f),
+                        SizeFlagsVertical = SizeFlags.FillExpand,
+                        SizeFlagsHorizontal = SizeFlags.FillExpand,
+                        Children =
+                        {
+                            (_resultsGrid = new GridContainer
+                            {
+                                MaxWidth = 300
+                            })
+                        }
+                    }
+                }
+            });
+
+            // populate filters from search tags
+            var filterTags = new List<string>();
+            foreach (var action in _actionManager.EnumerateActions())
+            {
+                filterTags.AddRange(action.Filters);
+            }
+
+            // special one to filter to only include item actions
+            filterTags.Add(ItemTag);
+            filterTags.Add(NotItemTag);
+            filterTags.Add(InstantActionTag);
+            filterTags.Add(ToggleActionTag);
+            filterTags.Add(TargetActionTag);
+            filterTags.Add(AllActionsTag);
+            filterTags.Add(GrantedActionsTag);
+
+            foreach (var tag in filterTags.Distinct().OrderBy(tag => tag))
+            {
+                _filterButton.AddItem( CultureInfo.CurrentCulture.TextInfo.ToTitleCase(tag), tag);
+            }
+
+            UpdateFilterLabel();
+
+            _dragShadow = new TextureRect
+            {
+                CustomMinimumSize = (64, 64),
+                Stretch = TextureRect.StretchMode.Scale,
+                Visible = false
+            };
+            UserInterfaceManager.PopupRoot.AddChild(_dragShadow);
+            LayoutContainer.SetSize(_dragShadow, (64, 64));
+
+            _dragDropHelper = new DragDropHelper<ActionMenuItem>(OnBeginActionDrag, OnContinueActionDrag, OnEndActionDrag);
+        }
+
+
+        protected override void EnteredTree()
+        {
+            base.EnteredTree();
+            _clearButton.OnPressed += OnClearButtonPressed;
+            _searchBar.OnTextChanged += OnSearchTextChanged;
+            _filterButton.OnItemSelected += OnFilterItemSelected;
+
+            foreach (var actionMenuControl in _resultsGrid.Children)
+            {
+                var actionMenuItem = (actionMenuControl as ActionMenuItem);
+                actionMenuItem.OnButtonDown += OnItemButtonDown;
+                actionMenuItem.OnButtonUp += OnItemButtonUp;
+                actionMenuItem.OnPressed += OnItemPressed;
+            }
+        }
+
+        protected override void ExitedTree()
+        {
+            base.ExitedTree();
+            _clearButton.OnPressed -= OnClearButtonPressed;
+            _searchBar.OnTextChanged -= OnSearchTextChanged;
+            _filterButton.OnItemSelected -= OnFilterItemSelected;
+
+            foreach (var actionMenuControl in _resultsGrid.Children)
+            {
+                var actionMenuItem = (actionMenuControl as ActionMenuItem);
+                actionMenuItem.OnButtonDown -= OnItemButtonDown;
+                actionMenuItem.OnButtonUp -= OnItemButtonUp;
+                actionMenuItem.OnPressed -= OnItemPressed;
+            }
+        }
+
+        private void OnFilterItemSelected(MultiselectOptionButton<string>.ItemPressedEventArgs args)
+        {
+            UpdateFilterLabel();
+            SearchAndDisplay();
+        }
+
+        protected override void Resized()
+        {
+            base.Resized();
+            // TODO: Can rework this once https://github.com/space-wizards/RobustToolbox/issues/1392 is done,
+            // currently no good way to let the grid know what size it has to "work with", so must manually resize
+            _resultsGrid.MaxWidth = Width;
+        }
+
+        private bool OnBeginActionDrag()
+        {
+            _dragShadow.Texture = _dragDropHelper.Dragged.Action.Icon.Frame0();
+            // don't make visible until frameupdate, otherwise it'll flicker
+            LayoutContainer.SetPosition(_dragShadow, UserInterfaceManager.MousePositionScaled - (32, 32));
+            return true;
+        }
+
+        private bool OnContinueActionDrag(float frameTime)
+        {
+            // keep dragged entity centered under mouse
+            LayoutContainer.SetPosition(_dragShadow, UserInterfaceManager.MousePositionScaled - (32, 32));
+            // we don't set this visible until frameupdate, otherwise it flickers
+            _dragShadow.Visible = true;
+            return true;
+        }
+
+        private void OnEndActionDrag()
+        {
+            _dragShadow.Visible = false;
+        }
+
+        private void OnItemButtonDown(BaseButton.ButtonEventArgs args)
+        {
+            if (args.Event.Function != EngineKeyFunctions.UIClick) return;
+            _dragDropHelper.MouseDown(args.Button as ActionMenuItem);
+        }
+
+        private void OnItemButtonUp(BaseButton.ButtonEventArgs args)
+        {
+            // note the buttonup only fires on the control that was originally
+            // pressed to initiate the drag, NOT the one we are currently hovering
+            if (args.Event.Function != EngineKeyFunctions.UIClick) return;
+
+            if (UserInterfaceManager.CurrentlyHovered is ActionSlot targetSlot)
+            {
+                if (!_dragDropHelper.IsDragging || _dragDropHelper.Dragged?.Action == null)
+                {
+                    _dragDropHelper.EndDrag();
+                    return;
+                }
+
+                // drag and drop
+                switch (_dragDropHelper.Dragged.Action)
+                {
+                    // assign the dragged action to the target slot
+                    case ActionPrototype actionPrototype:
+                        _actionsComponent.Assignments.AssignSlot(_actionsUI.SelectedHotbar, targetSlot.SlotIndex, ActionAssignment.For(actionPrototype.ActionType));
+                        break;
+                    case ItemActionPrototype itemActionPrototype:
+                        // the action menu doesn't show us if the action has an associated item,
+                        // so when we perform the assignment, we should check if we currently have an unassigned state
+                        // for this item and assign it tied to that item if so, otherwise assign it "itemless"
+
+                        // this is not particularly efficient but we don't maintain an index from
+                        // item action type to its action states, and this method should be pretty infrequent so it's probably fine
+                        var assigned = false;
+                        foreach (var (item, itemStates) in _actionsComponent.ItemActionStates())
+                        {
+                            foreach (var (actionType, _) in itemStates)
+                            {
+                                if (actionType != itemActionPrototype.ActionType) continue;
+                                var assignment = ActionAssignment.For(actionType, item);
+                                if (_actionsComponent.Assignments.HasAssignment(assignment)) continue;
+                                // no assignment for this state, assign tied to the item
+                                assigned = true;
+                                _actionsComponent.Assignments.AssignSlot(_actionsUI.SelectedHotbar, targetSlot.SlotIndex, assignment);
+                                break;
+                            }
+
+                            if (assigned)
+                            {
+                                break;
+                            }
+                        }
+
+                        if (!assigned)
+                        {
+                            _actionsComponent.Assignments.AssignSlot(_actionsUI.SelectedHotbar, targetSlot.SlotIndex, ActionAssignment.For(itemActionPrototype.ActionType));
+                        }
+                        break;
+                }
+
+                _actionsUI.UpdateUI();
+            }
+
+            _dragDropHelper.EndDrag();
+        }
+
+        private void OnItemPressed(BaseButton.ButtonEventArgs args)
+        {
+            if (args.Button is not ActionMenuItem actionMenuItem) return;
+            switch (actionMenuItem.Action)
+            {
+                case ActionPrototype actionPrototype:
+                    _actionsComponent.Assignments.AutoPopulate(ActionAssignment.For(actionPrototype.ActionType), _actionsUI.SelectedHotbar);
+                    break;
+                case ItemActionPrototype itemActionPrototype:
+                    _actionsComponent.Assignments.AutoPopulate(ActionAssignment.For(itemActionPrototype.ActionType), _actionsUI.SelectedHotbar);
+                    break;
+                default:
+                    Logger.ErrorS("action", "unexpected action prototype {0}", actionMenuItem.Action);
+                    break;
+            }
+
+            _actionsUI.UpdateUI();
+        }
+
+        private void OnClearButtonPressed(BaseButton.ButtonEventArgs args)
+        {
+            _searchBar.Clear();
+            _filterButton.DeselectAll();
+            UpdateFilterLabel();
+            SearchAndDisplay();
+        }
+
+        private void OnSearchTextChanged(LineEdit.LineEditEventArgs obj)
+        {
+            SearchAndDisplay();
+        }
+
+        private void SearchAndDisplay()
+        {
+            var search = Standardize(_searchBar.Text);
+            // only display nothing if there are no filters selected and text is not long enough.
+            // otherwise we will search if even one filter is applied, regardless of length of search string
+            if (_filterButton.SelectedKeys.Count == 0 &&
+                (string.IsNullOrWhiteSpace(search) || search.Length < MinSearchLength))
+            {
+                ClearList();
+                return;
+            }
+
+            var matchingActions = _actionManager.EnumerateActions()
+                .Where(a => MatchesSearchCriteria(a, search, _filterButton.SelectedKeys));
+
+            PopulateActions(matchingActions);
+        }
+
+        private void UpdateFilterLabel()
+        {
+            if (_filterButton.SelectedKeys.Count == 0)
+            {
+                _filterLabel.Visible = false;
+            }
+            else
+            {
+                _filterLabel.Visible = true;
+                _filterLabel.Text = Loc.GetString("Filters: {0}", string.Join(", ", _filterButton.SelectedLabels));
+            }
+        }
+
+        private bool MatchesSearchCriteria(BaseActionPrototype action, string standardizedSearch,
+            IReadOnlyList<string> selectedFilterTags)
+        {
+            // check filter tag match first - each action must contain all filter tags currently selected.
+            // if no tags selected, don't check tags
+            if (selectedFilterTags.Count > 0 && selectedFilterTags.Any(filterTag => !ActionMatchesFilterTag(action, filterTag)))
+            {
+                return false;
+            }
+
+            // check search tag match against the search query
+            if (action.Keywords.Any(standardizedSearch.Contains))
+            {
+                return true;
+            }
+
+            if (Standardize(ActionTypeString(action)).Contains(standardizedSearch))
+            {
+                return true;
+            }
+
+            // allows matching by typing spaces between the enum case changes, like "xeno spit" if the
+            // actiontype is "XenoSpit"
+            if (Standardize(ActionTypeString(action), true).Contains(standardizedSearch))
+            {
+                return true;
+            }
+
+            if (Standardize(action.Name.ToString()).Contains(standardizedSearch))
+            {
+                return true;
+            }
+
+            return false;
+
+        }
+
+        private string ActionTypeString(BaseActionPrototype baseActionPrototype)
+        {
+            if (baseActionPrototype is ActionPrototype actionPrototype)
+            {
+                return actionPrototype.ActionType.ToString();
+            }
+            if (baseActionPrototype is ItemActionPrototype itemActionPrototype)
+            {
+                return itemActionPrototype.ActionType.ToString();
+            }
+            throw new InvalidOperationException();
+        }
+
+        private bool ActionMatchesFilterTag(BaseActionPrototype action, string tag)
+        {
+            return tag switch
+            {
+                AllActionsTag => true,
+                GrantedActionsTag => _actionsComponent.IsGranted(action),
+                ItemTag => action is ItemActionPrototype,
+                NotItemTag => action is ActionPrototype,
+                InstantActionTag => action.BehaviorType == BehaviorType.Instant,
+                TargetActionTag => action.BehaviorType == BehaviorType.TargetEntity ||
+                                   action.BehaviorType == BehaviorType.TargetPoint,
+                ToggleActionTag => action.BehaviorType == BehaviorType.Toggle,
+                _ => action.Filters.Contains(tag)
+            };
+        }
+
+
+        /// <summary>
+        /// Standardized form is all lowercase, no non-alphanumeric characters (converted to whitespace),
+        /// trimmed, 1 space max per whitespace gap,
+        /// and optional spaces between case change
+        /// </summary>
+        private static string Standardize(string rawText, bool splitOnCaseChange = false)
+        {
+            rawText ??= "";
+
+            // treat non-alphanumeric characters as whitespace
+            rawText = NonAlphanumeric.Replace(rawText, " ");
+
+            // trim spaces and reduce internal whitespaces to 1 max
+            rawText = Whitespace.Replace(rawText, " ").Trim();
+            if (splitOnCaseChange)
+            {
+                // insert a space when case switches from lower to upper
+                rawText = AddSpaces(rawText, true);
+            }
+
+            return rawText.ToLowerInvariant().Trim();
+        }
+
+        // taken from https://stackoverflow.com/a/272929 (CC BY-SA 3.0)
+        private static string AddSpaces(string text, bool preserveAcronyms)
+        {
+            if (string.IsNullOrWhiteSpace(text))
+                return string.Empty;
+            var newText = new StringBuilder(text.Length * 2);
+            newText.Append(text[0]);
+            for (var i = 1; i < text.Length; i++)
+            {
+                if (char.IsUpper(text[i]))
+                {
+                    if ((text[i - 1] != ' ' && !char.IsUpper(text[i - 1])) ||
+                        (preserveAcronyms && char.IsUpper(text[i - 1]) &&
+                         i < text.Length - 1 && !char.IsUpper(text[i + 1])))
+                        newText.Append(' ');
+                }
+
+                newText.Append(text[i]);
+            }
+            return newText.ToString();
+        }
+
+        private void PopulateActions(IEnumerable<BaseActionPrototype> actions)
+        {
+            ClearList();
+
+            _actionList = actions.ToArray();
+            foreach (var action in _actionList.OrderBy(act => act.Name.ToString()))
+            {
+                var actionItem = new ActionMenuItem(action);
+                _resultsGrid.Children.Add(actionItem);
+                actionItem.SetActionState(_actionsComponent.IsGranted(action));
+
+                actionItem.OnButtonDown += OnItemButtonDown;
+                actionItem.OnButtonUp += OnItemButtonUp;
+                actionItem.OnPressed += OnItemPressed;
+            }
+        }
+
+        private void ClearList()
+        {
+            // TODO: Not sure if this unsub is needed if children are all being cleared
+            foreach (var actionItem in _resultsGrid.Children)
+            {
+                ((ActionMenuItem) actionItem).OnPressed -= OnItemPressed;
+            }
+            _resultsGrid.Children.Clear();
+            _actionList = EmptyActionList;
+        }
+
+        /// <summary>
+        /// Should be invoked when action states change, ensures
+        /// currently displayed actions are properly showing their revoked / granted status
+        /// </summary>
+        public void UpdateUI()
+        {
+            foreach (var actionItem in _resultsGrid.Children)
+            {
+                var actionMenuItem = ((ActionMenuItem) actionItem);
+                actionMenuItem.SetActionState(_actionsComponent.IsGranted(actionMenuItem.Action));
+            }
+        }
+
+        protected override void FrameUpdate(FrameEventArgs args)
+        {
+            base.Update(args);
+            _dragDropHelper.Update(args.DeltaSeconds);
+        }
+    }
+}

Content.Client/UserInterface/ActionMenuItem.cs

@@ -0,0 +1,68 @@
+#nullable enable
+
+using Content.Client.UserInterface.Stylesheets;
+using Content.Shared.Actions;
+using Robust.Client.UserInterface;
+using Robust.Client.UserInterface.Controls;
+using Robust.Client.Utility;
+
+namespace Content.Client.UserInterface
+{
+    /// <summary>
+    /// An individual action visible in the action menu.
+    /// </summary>
+    public class ActionMenuItem : ContainerButton
+    {
+        // shorter than default tooltip delay so user can
+        // quickly explore what each action is
+        private const float CustomTooltipDelay = 0.2f;
+
+        public BaseActionPrototype Action { get; private set; }
+
+        public ActionMenuItem(BaseActionPrototype action)
+        {
+            Action = action;
+
+            CustomMinimumSize = (64, 64);
+            SizeFlagsVertical = SizeFlags.None;
+
+            AddChild(new TextureRect
+            {
+                SizeFlagsHorizontal = SizeFlags.FillExpand,
+                SizeFlagsVertical = SizeFlags.FillExpand,
+                Stretch = TextureRect.StretchMode.Scale,
+                Texture = action.Icon.Frame0()
+            });
+
+            TooltipDelay = CustomTooltipDelay;
+            TooltipSupplier = SupplyTooltip;
+        }
+
+        private Control SupplyTooltip(Control? sender)
+        {
+            return new ActionAlertTooltip(Action.Name, Action.Description, Action.Requires);
+        }
+
+        /// <summary>
+        /// Change how this is displayed depending on if it is granted or revoked
+        /// </summary>
+        public void SetActionState(bool granted)
+        {
+            if (granted)
+            {
+                if (HasStyleClass(StyleNano.StyleClassActionMenuItemRevoked))
+                {
+                    RemoveStyleClass(StyleNano.StyleClassActionMenuItemRevoked);
+                }
+            }
+            else
+            {
+                if (!HasStyleClass(StyleNano.StyleClassActionMenuItemRevoked))
+                {
+                    AddStyleClass(StyleNano.StyleClassActionMenuItemRevoked);
+                }
+            }
+        }
+
+    }
+}

Content.Client/UserInterface/ActionsUI.cs

@@ -0,0 +1,556 @@
+#nullable enable
+using System.Collections.Generic;
+using Content.Client.GameObjects.Components.Mobs;
+using Content.Client.GameObjects.Components.Mobs.Actions;
+using Content.Client.UserInterface.Controls;
+using Content.Client.UserInterface.Stylesheets;
+using Content.Client.Utility;
+using Content.Shared.Actions;
+using Robust.Client.Graphics;
+using Robust.Client.Interfaces.ResourceManagement;
+using Robust.Client.UserInterface;
+using Robust.Client.UserInterface.Controls;
+using Robust.Client.Utility;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Input;
+using Robust.Shared.Input.Binding;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Timing;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Robust.Shared.Maths;
+using Robust.Shared.Timing;
+
+namespace Content.Client.UserInterface
+{
+    /// <summary>
+    ///     The action hotbar on the left side of the screen.
+    /// </summary>
+    public sealed class ActionsUI : Container
+    {
+        private readonly ClientActionsComponent _actionsComponent;
+        private readonly ActionManager _actionManager;
+        private readonly IEntityManager _entityManager;
+        private readonly IGameTiming _gameTiming;
+
+        private readonly ActionSlot[] _slots;
+
+        private readonly GridContainer _slotContainer;
+
+        private readonly TextureButton _lockButton;
+        private readonly TextureButton _settingsButton;
+        private readonly TextureButton _previousHotbarButton;
+        private readonly Label _loadoutNumber;
+        private readonly TextureButton _nextHotbarButton;
+        private readonly Texture _lockTexture;
+        private readonly Texture _unlockTexture;
+
+        private readonly TextureRect _dragShadow;
+
+        private readonly ActionMenu _menu;
+
+        /// <summary>
+        /// Index of currently selected hotbar
+        /// </summary>
+        public byte SelectedHotbar { get; private set; }
+
+        /// <summary>
+        /// Action slot we are currently selecting a target for.
+        /// </summary>
+        public ActionSlot? SelectingTargetFor { get; private set; }
+
+        /// <summary>
+        /// Drag drop helper for coordinating drag drops between action slots
+        /// </summary>
+        public DragDropHelper<ActionSlot> DragDropHelper { get; }
+
+        /// <summary>
+        /// Whether the bar is currently locked by the user. This is intended to prevent drag / drop
+        /// and right click clearing slots. Anything else is still doable.
+        /// </summary>
+        public bool Locked { get; private set; }
+
+        /// <summary>
+        /// All the action slots in order.
+        /// </summary>
+        public IEnumerable<ActionSlot> Slots => _slots;
+
+        public ActionsUI(ClientActionsComponent actionsComponent)
+        {
+            _actionsComponent = actionsComponent;
+            _actionManager = IoCManager.Resolve<ActionManager>();
+            _entityManager = IoCManager.Resolve<IEntityManager>();
+            _gameTiming = IoCManager.Resolve<IGameTiming>();
+            _menu = new ActionMenu(_actionsComponent, this);
+            LayoutContainer.SetGrowHorizontal(this, LayoutContainer.GrowDirection.End);
+            LayoutContainer.SetGrowVertical(this, LayoutContainer.GrowDirection.End);
+            LayoutContainer.SetAnchorTop(this, 0f);
+            LayoutContainer.SetAnchorBottom(this, 0.8f);
+            LayoutContainer.SetMarginLeft(this, 10);
+            LayoutContainer.SetMarginTop(this, 100);
+
+            SizeFlagsHorizontal = SizeFlags.None;
+            SizeFlagsVertical = SizeFlags.FillExpand;
+
+            var resourceCache = IoCManager.Resolve<IResourceCache>();
+
+            // everything needs to go within an inner panel container so the panel resizes to fit the elements.
+            // Because ActionsUI is being anchored by layoutcontainer, the hotbar backing would appear too tall
+            // if ActionsUI was the panel container
+
+            var panelContainer = new PanelContainer()
+            {
+                StyleClasses = {StyleNano.StyleClassHotbarPanel},
+                SizeFlagsHorizontal = SizeFlags.None,
+                SizeFlagsVertical = SizeFlags.None
+            };
+            AddChild(panelContainer);
+
+            var hotbarContainer = new VBoxContainer
+            {
+                SeparationOverride = 3,
+                SizeFlagsHorizontal = SizeFlags.None
+            };
+            panelContainer.AddChild(hotbarContainer);
+
+            var settingsContainer = new HBoxContainer
+            {
+                SizeFlagsHorizontal = SizeFlags.FillExpand
+            };
+            hotbarContainer.AddChild(settingsContainer);
+
+            settingsContainer.AddChild(new Control { SizeFlagsHorizontal = SizeFlags.FillExpand, SizeFlagsStretchRatio = 1 });
+            _lockTexture = resourceCache.GetTexture("/Textures/Interface/Nano/lock.svg.png");
+            _unlockTexture = resourceCache.GetTexture("/Textures/Interface/Nano/lock_open.svg.png");
+            _lockButton = new TextureButton
+            {
+                TextureNormal = _unlockTexture,
+                SizeFlagsHorizontal = SizeFlags.ShrinkCenter,
+                SizeFlagsVertical = SizeFlags.ShrinkCenter,
+                SizeFlagsStretchRatio = 1
+            };
+            settingsContainer.AddChild(_lockButton);
+            settingsContainer.AddChild(new Control { SizeFlagsHorizontal = SizeFlags.FillExpand, SizeFlagsStretchRatio = 2 });
+            _settingsButton = new TextureButton
+            {
+                TextureNormal = resourceCache.GetTexture("/Textures/Interface/Nano/gear.svg.png"),
+                SizeFlagsHorizontal = SizeFlags.ShrinkCenter,
+                SizeFlagsVertical = SizeFlags.ShrinkCenter,
+                SizeFlagsStretchRatio = 1
+            };
+            settingsContainer.AddChild(_settingsButton);
+            settingsContainer.AddChild(new Control { SizeFlagsHorizontal = SizeFlags.FillExpand, SizeFlagsStretchRatio = 1 });
+
+            // this allows a 2 column layout if window gets too small
+            _slotContainer = new GridContainer
+            {
+                MaxHeight = CalcMaxHeight()
+            };
+            hotbarContainer.AddChild(_slotContainer);
+
+            var loadoutContainer = new HBoxContainer
+            {
+                SizeFlagsHorizontal = SizeFlags.FillExpand
+            };
+            hotbarContainer.AddChild(loadoutContainer);
+
+            loadoutContainer.AddChild(new Control { SizeFlagsHorizontal = SizeFlags.FillExpand, SizeFlagsStretchRatio = 1 });
+            _previousHotbarButton = new TextureButton
+            {
+                TextureNormal = resourceCache.GetTexture("/Textures/Interface/Nano/left_arrow.svg.png"),
+                SizeFlagsHorizontal = SizeFlags.ShrinkCenter,
+                SizeFlagsVertical = SizeFlags.ShrinkCenter,
+                SizeFlagsStretchRatio = 1
+            };
+            loadoutContainer.AddChild(_previousHotbarButton);
+            loadoutContainer.AddChild(new Control { SizeFlagsHorizontal = SizeFlags.FillExpand, SizeFlagsStretchRatio = 2 });
+            _loadoutNumber = new Label
+            {
+                Text = "1",
+                SizeFlagsStretchRatio = 1
+            };
+            loadoutContainer.AddChild(_loadoutNumber);
+            loadoutContainer.AddChild(new Control { SizeFlagsHorizontal = SizeFlags.FillExpand, SizeFlagsStretchRatio = 2 });
+            _nextHotbarButton = new TextureButton
+            {
+                TextureNormal = resourceCache.GetTexture("/Textures/Interface/Nano/right_arrow.svg.png"),
+                SizeFlagsHorizontal = SizeFlags.ShrinkCenter,
+                SizeFlagsVertical = SizeFlags.ShrinkCenter,
+                SizeFlagsStretchRatio = 1
+            };
+            loadoutContainer.AddChild(_nextHotbarButton);
+            loadoutContainer.AddChild(new Control { SizeFlagsHorizontal = SizeFlags.FillExpand, SizeFlagsStretchRatio = 1 });
+
+            _slots = new ActionSlot[ClientActionsComponent.Slots];
+
+            _dragShadow = new TextureRect
+            {
+                CustomMinimumSize = (64, 64),
+                Stretch = TextureRect.StretchMode.Scale,
+                Visible = false
+            };
+            UserInterfaceManager.PopupRoot.AddChild(_dragShadow);
+            LayoutContainer.SetSize(_dragShadow, (64, 64));
+
+            for (byte i = 0; i < ClientActionsComponent.Slots; i++)
+            {
+                var slot = new ActionSlot(this, actionsComponent, i);
+                _slotContainer.AddChild(slot);
+                _slots[i] = slot;
+            }
+
+            DragDropHelper = new DragDropHelper<ActionSlot>(OnBeginActionDrag, OnContinueActionDrag, OnEndActionDrag);
+        }
+
+        protected override void EnteredTree()
+        {
+            base.EnteredTree();
+            _lockButton.OnPressed += OnLockPressed;
+            _nextHotbarButton.OnPressed += NextHotbar;
+            _previousHotbarButton.OnPressed += PreviousHotbar;
+            _settingsButton.OnPressed += OnToggleActionsMenu;
+        }
+
+        protected override void ExitedTree()
+        {
+            base.ExitedTree();
+            StopTargeting();
+            _menu.Close();
+            _lockButton.OnPressed -= OnLockPressed;
+            _nextHotbarButton.OnPressed -= NextHotbar;
+            _previousHotbarButton.OnPressed -= PreviousHotbar;
+            _settingsButton.OnPressed -= OnToggleActionsMenu;
+        }
+
+        protected override Vector2 CalculateMinimumSize()
+        {
+            // allows us to shrink down to a 2-column layout minimum
+            return (10, 400);
+        }
+
+        protected override void Resized()
+        {
+            base.Resized();
+            _slotContainer.MaxHeight = CalcMaxHeight();
+        }
+
+        private float CalcMaxHeight()
+        {
+            // TODO: Can rework this once https://github.com/space-wizards/RobustToolbox/issues/1392 is done,
+            // this is here because there isn't currently a good way to allow the grid to adjust its height based
+            // on constraints, otherwise we would use anchors to lay it out
+
+            // it looks bad to have an uneven number of slots in the columns,
+            // so we either do a single column or 2 equal sized columns
+            if (Height < 650)
+            {
+                // 2 column
+                return 400;
+            }
+            else
+            {
+                // 1 column
+                return 900;
+            }
+        }
+
+        protected override void UIScaleChanged()
+        {
+            _slotContainer.MaxHeight = CalcMaxHeight();
+            base.UIScaleChanged();
+        }
+
+        /// <summary>
+        /// Refresh the display of all the slots in the currently displayed hotbar,
+        /// to reflect the current component state and assignments of actions component.
+        /// </summary>
+        public void UpdateUI()
+        {
+            _menu.UpdateUI();
+
+            foreach (var actionSlot in Slots)
+            {
+                var assignedActionType = _actionsComponent.Assignments[SelectedHotbar, actionSlot.SlotIndex];
+                if (!assignedActionType.HasValue)
+                {
+                    actionSlot.Clear();
+                    continue;
+                }
+
+                if (assignedActionType.Value.TryGetAction(out var actionType))
+                {
+                    UpdateActionSlot(actionType, actionSlot, assignedActionType);
+                }
+                else if (assignedActionType.Value.TryGetItemActionWithoutItem(out var itemlessActionType))
+                {
+                    UpdateActionSlot(itemlessActionType, actionSlot, assignedActionType);
+                }
+                else if (assignedActionType.Value.TryGetItemActionWithItem(out var itemActionType, out var item))
+                {
+                    UpdateActionSlot(item, itemActionType, actionSlot, assignedActionType);
+                }
+                else
+                {
+                    Logger.ErrorS("action", "unexpected Assignment type {0}",
+                        assignedActionType.Value.Assignment);
+                    actionSlot.Clear();
+                }
+            }
+        }
+
+        private void UpdateActionSlot(ActionType actionType, ActionSlot actionSlot, ActionAssignment? assignedActionType)
+        {
+            if (_actionManager.TryGet(actionType, out var action))
+            {
+                actionSlot.Assign(action, true);
+            }
+            else
+            {
+                Logger.ErrorS("action", "unrecognized actionType {0}", assignedActionType);
+                actionSlot.Clear();
+                return;
+            }
+
+            if (!_actionsComponent.TryGetActionState(actionType, out var actionState) || !actionState.Enabled)
+            {
+                // action is currently disabled
+
+                // just revoked an action we were trying to target with, stop targeting
+                if (SelectingTargetFor?.Action != null && SelectingTargetFor.Action == action)
+                {
+                    StopTargeting();
+                }
+
+                actionSlot.DisableAction();
+                actionSlot.Cooldown = null;
+            }
+            else
+            {
+                // action is currently granted
+                actionSlot.EnableAction();
+                actionSlot.Cooldown = actionState.Cooldown;
+
+                // if we are targeting with an action now on cooldown, stop targeting
+                if (SelectingTargetFor?.Action != null && SelectingTargetFor.Action == action &&
+                    actionState.IsOnCooldown(_gameTiming))
+                {
+                    StopTargeting();
+                }
+            }
+
+            // check if we need to toggle it
+            if (action.BehaviorType == BehaviorType.Toggle)
+            {
+                actionSlot.ToggledOn = actionState.ToggledOn;
+            }
+        }
+
+        private void UpdateActionSlot(ItemActionType itemlessActionType, ActionSlot actionSlot,
+            ActionAssignment? assignedActionType)
+        {
+            if (_actionManager.TryGet(itemlessActionType, out var action))
+            {
+                actionSlot.Assign(action);
+            }
+            else
+            {
+                Logger.ErrorS("action", "unrecognized actionType {0}", assignedActionType);
+                actionSlot.Clear();
+            }
+            actionSlot.Cooldown = null;
+        }
+
+        private void UpdateActionSlot(EntityUid item, ItemActionType itemActionType, ActionSlot actionSlot,
+            ActionAssignment? assignedActionType)
+        {
+            if (!_entityManager.TryGetEntity(item, out var itemEntity)) return;
+            if (_actionManager.TryGet(itemActionType, out var action))
+            {
+                actionSlot.Assign(action, itemEntity, true);
+            }
+            else
+            {
+                Logger.ErrorS("action", "unrecognized actionType {0}", assignedActionType);
+                actionSlot.Clear();
+                return;
+            }
+
+            if (!_actionsComponent.TryGetItemActionState(itemActionType, item, out var actionState))
+            {
+                // action is no longer tied to an item, this should never happen as we
+                // check this at the start of this method. But just to be safe
+                // we will restore our assignment here to the correct state
+                Logger.ErrorS("action", "coding error, expected actionType {0} to have" +
+                                          " a state but it didn't", assignedActionType);
+                _actionsComponent.Assignments.AssignSlot(SelectedHotbar, actionSlot.SlotIndex,
+                    ActionAssignment.For(itemActionType));
+                actionSlot.Assign(action);
+                return;
+            }
+
+            if (!actionState.Enabled)
+            {
+                // just disabled an action we were trying to target with, stop targeting
+                if (SelectingTargetFor?.Action != null && SelectingTargetFor.Action == action)
+                {
+                    StopTargeting();
+                }
+
+                actionSlot.DisableAction();
+            }
+            else
+            {
+                // action is currently granted
+                actionSlot.EnableAction();
+
+                // if we are targeting with an action now on cooldown, stop targeting
+                if (SelectingTargetFor?.Action != null && SelectingTargetFor.Action == action &&
+                    SelectingTargetFor.Item == itemEntity &&
+                    actionState.IsOnCooldown(_gameTiming))
+                {
+                    StopTargeting();
+                }
+            }
+            actionSlot.Cooldown = actionState.Cooldown;
+
+            // check if we need to toggle it
+            if (action.BehaviorType == BehaviorType.Toggle)
+            {
+                actionSlot.ToggledOn = actionState.ToggledOn;
+            }
+        }
+
+        private void NextHotbar(BaseButton.ButtonEventArgs args)
+        {
+            ChangeHotbar((byte) ((SelectedHotbar + 1) % ClientActionsComponent.Hotbars));
+        }
+
+        private void PreviousHotbar(BaseButton.ButtonEventArgs args)
+        {
+            var newBar = SelectedHotbar == 0 ? ClientActionsComponent.Hotbars - 1 : SelectedHotbar - 1;
+            ChangeHotbar((byte) newBar);
+        }
+
+
+        private void ChangeHotbar(byte hotbar)
+        {
+            StopTargeting();
+            SelectedHotbar = hotbar;
+            _loadoutNumber.Text = (hotbar + 1).ToString();
+            UpdateUI();
+        }
+
+        /// <summary>
+        /// If currently targeting with this slot, stops targeting.
+        /// If currently targeting with no slot or a different slot, switches to
+        /// targeting with the specified slot.
+        /// </summary>
+        /// <param name="slot"></param>
+        public void ToggleTargeting(ActionSlot slot)
+        {
+            if (SelectingTargetFor == slot)
+            {
+                StopTargeting();
+                return;
+            }
+            StartTargeting(slot);
+        }
+
+        /// <summary>
+        /// Puts us in targeting mode, where we need to pick either a target point or entity
+        /// </summary>
+        private void StartTargeting(ActionSlot actionSlot)
+        {
+            // If we were targeting something else we should stop
+            StopTargeting();
+
+            SelectingTargetFor = actionSlot;
+
+            // show it as toggled on to indicate we are currently selecting a target for it
+            if (!actionSlot.ToggledOn)
+            {
+                actionSlot.ToggledOn = true;
+            }
+        }
+
+        /// <summary>
+        /// Switch out of targeting mode if currently selecting target for an action
+        /// </summary>
+        public void StopTargeting()
+        {
+            if (SelectingTargetFor == null) return;
+            if (SelectingTargetFor.ToggledOn)
+            {
+                SelectingTargetFor.ToggledOn = false;
+            }
+            SelectingTargetFor = null;
+        }
+
+        private void OnToggleActionsMenu(BaseButton.ButtonEventArgs args)
+        {
+            ToggleActionsMenu();
+        }
+
+        public void ToggleActionsMenu()
+        {
+            if (_menu.IsOpen)
+            {
+                _menu.Close();
+            }
+            else
+            {
+                _menu.OpenCentered();
+            }
+        }
+
+        private void OnLockPressed(BaseButton.ButtonEventArgs obj)
+        {
+            Locked = !Locked;
+            _lockButton.TextureNormal = Locked ? _lockTexture : _unlockTexture;
+        }
+
+        private bool OnBeginActionDrag()
+        {
+            // only initiate the drag if the slot has an action in it
+            if (Locked || DragDropHelper.Dragged.Action == null) return false;
+
+            _dragShadow.Texture = DragDropHelper.Dragged.Action.Icon.Frame0();
+            LayoutContainer.SetPosition(_dragShadow, UserInterfaceManager.MousePositionScaled - (32, 32));
+            DragDropHelper.Dragged.CancelPress();
+            return true;
+        }
+
+        private bool OnContinueActionDrag(float frameTime)
+        {
+            // stop if there's no action in the slot
+            if (Locked || DragDropHelper.Dragged.Action == null) return false;
+
+            // keep dragged entity centered under mouse
+            LayoutContainer.SetPosition(_dragShadow, UserInterfaceManager.MousePositionScaled - (32, 32));
+            // we don't set this visible until frameupdate, otherwise it flickers
+            _dragShadow.Visible = true;
+            return true;
+        }
+
+        private void OnEndActionDrag()
+        {
+            _dragShadow.Visible = false;
+        }
+
+        /// <summary>
+        /// Handle keydown / keyup for one of the slots via a keybinding, simulates mousedown/mouseup on it.
+        /// </summary>
+        /// <param name="slot">slot index to to receive the press (0 corresponds to the one labeled 1, 9 corresponds to the one labeled 0)</param>
+        public void HandleHotbarKeybind(byte slot, PointerInputCmdHandler.PointerInputCmdArgs args)
+        {
+            var actionSlot = _slots[slot];
+            actionSlot.Depress(args.State == BoundKeyState.Down);
+        }
+
+        protected override void FrameUpdate(FrameEventArgs args)
+        {
+            base.Update(args);
+            DragDropHelper.Update(args.DeltaSeconds);
+        }
+    }
+}

Content.Client/UserInterface/AlertsUI.cs

@@ -1,10 +1,8 @@
 using System;
 using Content.Client.UserInterface.Stylesheets;
-using Robust.Client.Graphics.Drawing;
 using Robust.Client.Interfaces.Graphics;
 using Robust.Client.UserInterface;
 using Robust.Client.UserInterface.Controls;
-using Robust.Client.UserInterface.CustomControls;
 using Robust.Shared.Maths;
 
 namespace Content.Client.UserInterface
@@ -16,58 +14,51 @@ namespace Content.Client.UserInterface
     {
         public GridContainer Grid { get; }
 
-        private readonly IClyde _clyde;
-
-        public AlertsUI(IClyde clyde)
+        public AlertsUI()
         {
-            _clyde = clyde;
+            LayoutContainer.SetGrowHorizontal(this, LayoutContainer.GrowDirection.Begin);
+            LayoutContainer.SetGrowVertical(this, LayoutContainer.GrowDirection.End);
+            LayoutContainer.SetAnchorTop(this, 0f);
+            LayoutContainer.SetAnchorRight(this, 1f);
+            LayoutContainer.SetAnchorBottom(this, 1f);
+            LayoutContainer.SetMarginBottom(this, -180);
+            LayoutContainer.SetMarginTop(this, 250);
+            LayoutContainer.SetMarginRight(this, -10);
             var panelContainer = new PanelContainer
             {
                 StyleClasses = {StyleNano.StyleClassTransparentBorderedWindowPanel},
-                SizeFlagsVertical = SizeFlags.FillExpand,
+                SizeFlagsHorizontal = SizeFlags.ShrinkEnd,
+                SizeFlagsVertical = SizeFlags.None
             };
             AddChild(panelContainer);
 
             Grid = new GridContainer
             {
-                MaxHeight = CalcMaxHeight(clyde.ScreenSize),
+                MaxHeight = 64,
                 ExpandBackwards = true
             };
             panelContainer.AddChild(Grid);
-            clyde.OnWindowResized += ClydeOnOnWindowResized;
-
-            LayoutContainer.SetGrowHorizontal(this, LayoutContainer.GrowDirection.Begin);
-            LayoutContainer.SetAnchorAndMarginPreset(this, LayoutContainer.LayoutPreset.TopRight, margin: 10);
-            LayoutContainer.SetMarginTop(this, 250);
         }
 
-        protected override void UIScaleChanged()
-        {
-            Grid.MaxHeight = CalcMaxHeight(_clyde.ScreenSize);
-            base.UIScaleChanged();
-        }
-
-        private void ClydeOnOnWindowResized(WindowResizedEventArgs obj)
+        protected override void Resized()
         {
             // TODO: Can rework this once https://github.com/space-wizards/RobustToolbox/issues/1392 is done,
             // this is here because there isn't currently a good way to allow the grid to adjust its height based
             // on constraints, otherwise we would use anchors to lay it out
-            Grid.MaxHeight = CalcMaxHeight(obj.NewSize);;
+            base.Resized();
+            Grid.MaxHeight = Height;
         }
 
-        private float CalcMaxHeight(Vector2i screenSize)
+        protected override Vector2 CalculateMinimumSize()
         {
-            return Math.Max(((screenSize.Y) / UIScale) - 420, 1);
+            // allows us to shrink down to a single row
+            return (64, 64);
         }
 
-        protected override void Dispose(bool disposing)
+        protected override void UIScaleChanged()
         {
-            base.Dispose(disposing);
-
-            if (disposing)
-            {
-                _clyde.OnWindowResized -= ClydeOnOnWindowResized;
-            }
+            Grid.MaxHeight = Height;
+            base.UIScaleChanged();
         }
     }
 }

Content.Client/UserInterface/Controls/ActionSlot.cs

@@ -0,0 +1,652 @@
+#nullable enable
+using System;
+using Content.Client.GameObjects.Components.Mobs;
+using Content.Client.UserInterface.Stylesheets;
+using Content.Shared.Actions;
+using Content.Shared.GameObjects.Components.Mobs;
+using Robust.Client.Graphics;
+using Robust.Client.Interfaces.GameObjects.Components;
+using Robust.Client.UserInterface;
+using Robust.Client.UserInterface.Controls;
+using Robust.Client.Utility;
+using Robust.Shared.Input;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Timing;
+using Robust.Shared.IoC;
+using Robust.Shared.Localization;
+using Robust.Shared.Maths;
+using Robust.Shared.Timing;
+using Robust.Shared.Utility;
+
+namespace Content.Client.UserInterface.Controls
+{
+    /// <summary>
+    /// A slot in the action hotbar. Not extending BaseButton because
+    /// its needs diverged too much.
+    /// </summary>
+    public class ActionSlot : PanelContainer
+    {
+        // shorter than default tooltip delay so user can more easily
+        // see what actions they've been given
+        private const float CustomTooltipDelay = 0.5f;
+
+        private static readonly string EnabledColor = "#7b7e9e";
+        private static readonly string DisabledColor = "#950000";
+
+        /// <summary>
+        /// Current action in this slot.
+        /// </summary>
+        public BaseActionPrototype? Action { get; private set; }
+
+        /// <summary>
+        /// true if there is an action assigned to the slot
+        /// </summary>
+        public bool HasAssignment => Action != null;
+
+        private bool HasToggleSprite => Action != null && Action.IconOn != SpriteSpecifier.Invalid;
+
+        /// <summary>
+        /// Only applicable when an action is in this slot.
+        /// True if the action is currently shown as enabled, false if action disabled.
+        /// </summary>
+        public bool ActionEnabled { get; private set; }
+
+        /// <summary>
+        /// Is there an action in the slot that can currently be used?
+        /// </summary>
+        public bool CanUseAction => HasAssignment && ActionEnabled && !IsOnCooldown;
+
+        /// <summary>
+        /// Item the action is provided by, only valid if Action is an ItemActionPrototype. May be null
+        /// if the item action is not yet tied to an item.
+        /// </summary>
+        public IEntity? Item { get; private set; }
+
+        /// <summary>
+        /// Whether the action in this slot should be shown as toggled on. Separate from Depressed.
+        /// </summary>
+        public bool ToggledOn
+        {
+            get => _toggledOn;
+            set
+            {
+                if (_toggledOn == value) return;
+                _toggledOn = value;
+                UpdateIcons();
+                DrawModeChanged();
+            }
+        }
+
+        /// <summary>
+        /// 1-10 corresponding to the number label on the slot (10 is labeled as 0)
+        /// </summary>
+        private byte SlotNumber => (byte) (SlotIndex + 1);
+        public byte SlotIndex { get; }
+
+        /// <summary>
+        /// Current cooldown displayed in this slot. Set to null to show no cooldown.
+        /// </summary>
+        public (TimeSpan Start, TimeSpan End)? Cooldown
+        {
+            get => _cooldown;
+            set
+            {
+                _cooldown = value;
+                if (SuppliedTooltip is ActionAlertTooltip actionAlertTooltip)
+                {
+                    actionAlertTooltip.Cooldown = value;
+                }
+            }
+        }
+        private (TimeSpan Start, TimeSpan End)? _cooldown;
+
+        public bool IsOnCooldown => Cooldown.HasValue && _gameTiming.CurTime < Cooldown.Value.End;
+
+        private readonly IGameTiming _gameTiming;
+        private readonly RichTextLabel _number;
+        private readonly TextureRect _bigActionIcon;
+        private readonly TextureRect _smallActionIcon;
+        private readonly SpriteView _smallItemSpriteView;
+        private readonly SpriteView _bigItemSpriteView;
+        private readonly CooldownGraphic _cooldownGraphic;
+        private readonly ActionsUI _actionsUI;
+        private readonly ClientActionsComponent _actionsComponent;
+        private bool _toggledOn;
+        // whether button is currently pressed down by mouse or keybind down.
+        private bool _depressed;
+        private bool _beingHovered;
+
+        /// <summary>
+        /// Creates an action slot for the specified number
+        /// </summary>
+        /// <param name="slotIndex">slot index this corresponds to, 0-9 (0 labeled as 1, 8, labeled "9", 9 labeled as "0".</param>
+        public ActionSlot(ActionsUI actionsUI, ClientActionsComponent actionsComponent, byte slotIndex)
+        {
+            _actionsComponent = actionsComponent;
+            _actionsUI = actionsUI;
+            _gameTiming = IoCManager.Resolve<IGameTiming>();
+            SlotIndex = slotIndex;
+            MouseFilter = MouseFilterMode.Stop;
+
+            CustomMinimumSize = (64, 64);
+            SizeFlagsVertical = SizeFlags.None;
+            TooltipDelay = CustomTooltipDelay;
+            TooltipSupplier = SupplyTooltip;
+
+            _number = new RichTextLabel
+            {
+                StyleClasses = {StyleNano.StyleClassHotbarSlotNumber}
+            };
+            _number.SetMessage(SlotNumberLabel());
+
+            _bigActionIcon = new TextureRect
+            {
+                SizeFlagsHorizontal = SizeFlags.FillExpand,
+                SizeFlagsVertical = SizeFlags.FillExpand,
+                Stretch = TextureRect.StretchMode.Scale,
+                Visible = false
+            };
+            _bigItemSpriteView = new SpriteView
+            {
+                SizeFlagsHorizontal = SizeFlags.FillExpand,
+                SizeFlagsVertical = SizeFlags.FillExpand,
+                Scale = (2,2),
+                Visible = false
+            };
+            _smallActionIcon = new TextureRect
+            {
+                SizeFlagsHorizontal = SizeFlags.ShrinkEnd,
+                SizeFlagsVertical = SizeFlags.ShrinkEnd,
+                Stretch = TextureRect.StretchMode.Scale,
+                Visible = false
+            };
+            _smallItemSpriteView = new SpriteView
+            {
+                SizeFlagsHorizontal = SizeFlags.ShrinkEnd,
+                SizeFlagsVertical = SizeFlags.ShrinkEnd,
+                Visible = false
+            };
+
+            _cooldownGraphic = new CooldownGraphic {Progress = 0, Visible = false};
+
+            // padding to the left of the number to shift it right
+            var paddingBox = new HBoxContainer()
+            {
+                SizeFlagsHorizontal = SizeFlags.FillExpand,
+                SizeFlagsVertical = SizeFlags.FillExpand,
+                CustomMinimumSize = (64, 64)
+            };
+            paddingBox.AddChild(new Control()
+            {
+                CustomMinimumSize = (4, 4),
+                SizeFlagsVertical = SizeFlags.Fill
+            });
+            paddingBox.AddChild(_number);
+
+            // padding to the left of the small icon
+            var paddingBoxItemIcon = new HBoxContainer()
+            {
+                SizeFlagsHorizontal = SizeFlags.FillExpand,
+                SizeFlagsVertical = SizeFlags.FillExpand,
+                CustomMinimumSize = (64, 64)
+            };
+            paddingBoxItemIcon.AddChild(new Control()
+            {
+                CustomMinimumSize = (32, 32),
+                SizeFlagsVertical = SizeFlags.Fill
+            });
+            paddingBoxItemIcon.AddChild(new Control
+            {
+                Children =
+                {
+                    _smallActionIcon,
+                    _smallItemSpriteView
+                }
+            });
+            AddChild(_bigActionIcon);
+            AddChild(_bigItemSpriteView);
+            AddChild(_cooldownGraphic);
+            AddChild(paddingBox);
+            AddChild(paddingBoxItemIcon);
+            DrawModeChanged();
+        }
+
+        private Control? SupplyTooltip(Control sender)
+        {
+            return Action == null ? null :
+                new ActionAlertTooltip(Action.Name, Action.Description, Action.Requires) {Cooldown = Cooldown};
+        }
+
+        /// <summary>
+        /// Action attempt for performing the action in the slot
+        /// </summary>
+        public IActionAttempt? ActionAttempt()
+        {
+            IActionAttempt? attempt = Action switch
+            {
+                ActionPrototype actionPrototype => new ActionAttempt(actionPrototype),
+                ItemActionPrototype itemActionPrototype =>
+                    (Item != null && Item.TryGetComponent<ItemActionsComponent>(out var itemActions)) ?
+                        new ItemActionAttempt(itemActionPrototype, Item, itemActions) : null,
+                _ => null
+            };
+            return attempt;
+        }
+
+        protected override void MouseEntered()
+        {
+            base.MouseEntered();
+
+            _beingHovered = true;
+            DrawModeChanged();
+            if (Action is not ItemActionPrototype) return;
+            if (Item == null) return;
+            _actionsComponent.HighlightItemSlot(Item);
+        }
+
+        protected override void MouseExited()
+        {
+            base.MouseExited();
+            _beingHovered = false;
+            CancelPress();
+            DrawModeChanged();
+            _actionsComponent.StopHighlightingItemSlots();
+        }
+
+        protected override void KeyBindDown(GUIBoundKeyEventArgs args)
+        {
+            base.KeyBindDown(args);
+
+            if (args.Function == EngineKeyFunctions.UIRightClick)
+            {
+                if (!_actionsUI.Locked && !_actionsUI.DragDropHelper.IsDragging)
+                {
+                    _actionsComponent.Assignments.ClearSlot(_actionsUI.SelectedHotbar, SlotIndex, true);
+                    _actionsUI.StopTargeting();
+                    _actionsUI.UpdateUI();
+                }
+                return;
+            }
+
+            // only handle clicks, and can't do anything to this if no assignment
+            if (args.Function != EngineKeyFunctions.UIClick || !HasAssignment)
+                return;
+
+            // might turn into a drag or a full press if released
+            Depress(true);
+            _actionsUI.DragDropHelper.MouseDown(this);
+            DrawModeChanged();
+        }
+
+        protected override void KeyBindUp(GUIBoundKeyEventArgs args)
+        {
+            base.KeyBindUp(args);
+
+            if (args.Function != EngineKeyFunctions.UIClick)
+                return;
+
+            // might be finishing a drag or using the action
+            if (_actionsUI.DragDropHelper.IsDragging &&
+                _actionsUI.DragDropHelper.Dragged == this &&
+                UserInterfaceManager.CurrentlyHovered is ActionSlot targetSlot &&
+                targetSlot != this)
+            {
+                // finish the drag, swap the 2 slots
+                var fromIdx = SlotIndex;
+                var fromAssignment = _actionsComponent.Assignments[_actionsUI.SelectedHotbar, fromIdx];
+                var toIdx = targetSlot.SlotIndex;
+                var toAssignment = _actionsComponent.Assignments[_actionsUI.SelectedHotbar, toIdx];
+
+                if (fromIdx == toIdx) return;
+                if (!fromAssignment.HasValue) return;
+
+                _actionsComponent.Assignments.AssignSlot(_actionsUI.SelectedHotbar, toIdx, fromAssignment.Value);
+                if (toAssignment.HasValue)
+                {
+                    _actionsComponent.Assignments.AssignSlot(_actionsUI.SelectedHotbar, fromIdx, toAssignment.Value);
+                }
+                else
+                {
+                    _actionsComponent.Assignments.ClearSlot(_actionsUI.SelectedHotbar, fromIdx, false);
+                }
+                _actionsUI.UpdateUI();
+            }
+            else
+            {
+                // perform the action
+                if (UserInterfaceManager.CurrentlyHovered == this)
+                {
+                    Depress(false);
+                }
+            }
+            _actionsUI.DragDropHelper.EndDrag();
+            DrawModeChanged();
+        }
+
+        /// <summary>
+        /// Cancel current press without triggering the action
+        /// </summary>
+        public void CancelPress()
+        {
+            _depressed = false;
+            DrawModeChanged();
+        }
+
+        /// <summary>
+        /// Press this button down. If it was depressed and now set to not depressed, will
+        /// trigger the action. Only has an effect if CanUseAction.
+        /// </summary>
+        public void Depress(bool depress)
+        {
+            if (!CanUseAction) return;
+
+            if (_depressed && !depress)
+            {
+                // fire the action
+                // no left-click interaction with it on cooldown or revoked
+                _actionsComponent.AttemptAction(this);
+            }
+            _depressed = depress;
+           DrawModeChanged();
+        }
+
+        /// <summary>
+        /// Updates the action assigned to this slot.
+        /// </summary>
+        /// <param name="action">action to assign</param>
+        /// <param name="actionEnabled">whether action should initially appear enable or disabled</param>
+        public void Assign(ActionPrototype action, bool actionEnabled)
+        {
+            // already assigned
+            if (Action != null && Action == action) return;
+
+            Action = action;
+            Item = null;
+            _depressed = false;
+            ToggledOn = false;
+            ActionEnabled = actionEnabled;
+            Cooldown = null;
+            HideTooltip();
+            UpdateIcons();
+            DrawModeChanged();
+            _number.SetMessage(SlotNumberLabel());
+        }
+
+        /// <summary>
+        /// Updates the item action assigned to this slot. The action will always be shown as disabled
+        /// until it is tied to a specific item.
+        /// </summary>
+        /// <param name="action">action to assign</param>
+        public void Assign(ItemActionPrototype action)
+        {
+            // already assigned
+            if (Action != null && Action == action && Item == null) return;
+
+            Action = action;
+            Item = null;
+            _depressed = false;
+            ToggledOn = false;
+            ActionEnabled = false;
+            Cooldown = null;
+            HideTooltip();
+            UpdateIcons();
+            DrawModeChanged();
+            _number.SetMessage(SlotNumberLabel());
+        }
+
+        /// <summary>
+        /// Updates the item action assigned to this slot, tied to a specific item.
+        /// </summary>
+        /// <param name="action">action to assign</param>
+        /// <param name="item">item the action is provided by</param>
+        /// <param name="actionEnabled">whether action should initially appear enable or disabled</param>
+        public void Assign(ItemActionPrototype action, IEntity item, bool actionEnabled)
+        {
+            // already assigned
+            if (Action != null && Action == action && Item == item) return;
+
+            Action = action;
+            Item = item;
+            _depressed = false;
+            ToggledOn = false;
+            ActionEnabled = false;
+            Cooldown = null;
+            HideTooltip();
+            UpdateIcons();
+            DrawModeChanged();
+            _number.SetMessage(SlotNumberLabel());
+        }
+
+        /// <summary>
+        /// Clears the action assigned to this slot
+        /// </summary>
+        public void Clear()
+        {
+            if (!HasAssignment) return;
+            Action = null;
+            Item = null;
+            ToggledOn = false;
+            _depressed = false;
+            Cooldown = null;
+            HideTooltip();
+            UpdateIcons();
+            DrawModeChanged();
+            _number.SetMessage(SlotNumberLabel());
+        }
+
+        /// <summary>
+        /// Display the action in this slot (if there is one) as enabled
+        /// </summary>
+        public void EnableAction()
+        {
+            if (ActionEnabled || !HasAssignment) return;
+
+            ActionEnabled = true;
+            _depressed = false;
+            DrawModeChanged();
+            _number.SetMessage(SlotNumberLabel());
+        }
+
+        /// <summary>
+        /// Display the action in this slot (if there is one) as disabled.
+        /// The slot is still clickable.
+        /// </summary>
+        public void DisableAction()
+        {
+            if (!ActionEnabled || !HasAssignment) return;
+
+            ActionEnabled = false;
+            _depressed = false;
+            DrawModeChanged();
+            _number.SetMessage(SlotNumberLabel());
+        }
+
+        private FormattedMessage SlotNumberLabel()
+        {
+            if (SlotNumber > 10) return FormattedMessage.FromMarkup("");
+            var number = Loc.GetString(SlotNumber == 10 ? "0" : SlotNumber.ToString());
+            var color = (ActionEnabled || !HasAssignment) ? EnabledColor : DisabledColor;
+            return FormattedMessage.FromMarkup("[color=" + color + "]" + number + "[/color]");
+        }
+
+        private void UpdateIcons()
+        {
+            if (!HasAssignment)
+            {
+                SetActionIcon(null);
+                SetItemIcon(null);
+                return;
+            }
+
+            if (HasToggleSprite && ToggledOn && Action != null)
+            {
+                SetActionIcon(Action.IconOn.Frame0());
+            }
+            else if (Action != null)
+            {
+                SetActionIcon(Action.Icon.Frame0());
+            }
+
+            if (Item != null)
+            {
+                SetItemIcon(Item.TryGetComponent<ISpriteComponent>(out var spriteComponent) ? spriteComponent : null);
+            }
+            else
+            {
+                SetItemIcon(null);
+            }
+        }
+
+        private void SetActionIcon(Texture? texture)
+        {
+            if (texture == null || !HasAssignment)
+            {
+                _bigActionIcon.Texture = null;
+                _bigActionIcon.Visible = false;
+                _smallActionIcon.Texture = null;
+                _smallActionIcon.Visible = false;
+            }
+            else
+            {
+                if (Action is ItemActionPrototype {IconStyle: ItemActionIconStyle.BigItem})
+                {
+                    _bigActionIcon.Texture = null;
+                    _bigActionIcon.Visible = false;
+                    _smallActionIcon.Texture = texture;
+                    _smallActionIcon.Visible = true;
+                }
+                else
+                {
+                    _bigActionIcon.Texture = texture;
+                    _bigActionIcon.Visible = true;
+                    _smallActionIcon.Texture = null;
+                    _smallActionIcon.Visible = false;
+                }
+
+            }
+        }
+
+        private void SetItemIcon(ISpriteComponent? sprite)
+        {
+            if (sprite == null || !HasAssignment)
+            {
+                _bigItemSpriteView.Visible = false;
+                _bigItemSpriteView.Sprite = null;
+                _smallItemSpriteView.Visible = false;
+                _smallItemSpriteView.Sprite = null;
+            }
+            else
+            {
+                if (Action is ItemActionPrototype actionPrototype)
+                {
+                    switch (actionPrototype.IconStyle)
+                    {
+                        case ItemActionIconStyle.BigItem:
+                        {
+                            _bigItemSpriteView.Visible = true;
+                            _bigItemSpriteView.Sprite = sprite;
+                            _smallItemSpriteView.Visible = false;
+                            _smallItemSpriteView.Sprite = null;
+                            break;
+                        }
+                        case ItemActionIconStyle.BigAction:
+                        {
+                            _bigItemSpriteView.Visible = false;
+                            _bigItemSpriteView.Sprite = null;
+                            _smallItemSpriteView.Visible = true;
+                            _smallItemSpriteView.Sprite = sprite;
+                            break;
+                        }
+                        case ItemActionIconStyle.NoItem:
+                        {
+                            _bigItemSpriteView.Visible = false;
+                            _bigItemSpriteView.Sprite = null;
+                            _smallItemSpriteView.Visible = false;
+                            _smallItemSpriteView.Sprite = null;
+                            break;
+                        }
+                    }
+
+                }
+                else
+                {
+                    _bigItemSpriteView.Visible = false;
+                    _bigItemSpriteView.Sprite = null;
+                    _smallItemSpriteView.Visible = false;
+                    _smallItemSpriteView.Sprite = null;
+                }
+
+            }
+        }
+
+
+        private void DrawModeChanged()
+        {
+            // always show the normal empty button style if no action in this slot
+            if (!HasAssignment)
+            {
+                SetOnlyStylePseudoClass(ContainerButton.StylePseudoClassNormal);
+                return;
+            }
+
+            // it's only depress-able if it's usable, so if we're depressed
+            // show the depressed style
+            if (_depressed)
+            {
+                SetOnlyStylePseudoClass(ContainerButton.StylePseudoClassPressed);
+                return;
+            }
+
+            // show a hover only if the action is usable
+            if (_beingHovered)
+            {
+                if (ActionEnabled && !IsOnCooldown)
+                {
+                    SetOnlyStylePseudoClass(ContainerButton.StylePseudoClassHover);
+                    return;
+                }
+            }
+
+            // if it's toggled on, always show the toggled on style (currently same as depressed style)
+            if (ToggledOn)
+            {
+                // when there's a toggle sprite, we're showing that sprite instead of highlighting this slot
+                SetOnlyStylePseudoClass(HasToggleSprite ? ContainerButton.StylePseudoClassNormal :
+                    ContainerButton.StylePseudoClassPressed);
+                return;
+            }
+
+
+            if (!ActionEnabled)
+            {
+                SetOnlyStylePseudoClass(ContainerButton.StylePseudoClassDisabled);
+                return;
+            }
+
+
+            SetOnlyStylePseudoClass(ContainerButton.StylePseudoClassNormal);
+        }
+
+
+
+        protected override void FrameUpdate(FrameEventArgs args)
+        {
+            base.FrameUpdate(args);
+            if (!Cooldown.HasValue)
+            {
+                _cooldownGraphic.Visible = false;
+                _cooldownGraphic.Progress = 0;
+                return;
+            }
+
+            var duration = Cooldown.Value.End - Cooldown.Value.Start;
+            var curTime = _gameTiming.CurTime;
+            var length = duration.TotalSeconds;
+            var progress = (curTime - Cooldown.Value.Start).TotalSeconds / length;
+            var ratio = (progress <= 1 ? (1 - progress) : (curTime - Cooldown.Value.End).TotalSeconds * -5);
+
+            _cooldownGraphic.Progress = MathHelper.Clamp((float)ratio, -1, 1);
+            _cooldownGraphic.Visible = ratio > -1f;
+        }
+    }
+}

Content.Client/UserInterface/Controls/AlertControl.cs

@@ -1,30 +1,48 @@
 #nullable enable
 using System;
-using Content.Client.UserInterface;
 using Content.Client.Utility;
 using Content.Shared.Alert;
 using Robust.Client.Interfaces.ResourceManagement;
+using Robust.Client.UserInterface;
 using Robust.Client.UserInterface.Controls;
+using Robust.Shared.Interfaces.Timing;
+using Robust.Shared.IoC;
 using Robust.Shared.Maths;
+using Robust.Shared.Timing;
 
-namespace Content.Client.GameObjects.Components.Mobs
+namespace Content.Client.UserInterface.Controls
 {
     public class AlertControl : BaseButton
     {
+        // shorter than default tooltip delay so user can more easily
+        // see what alerts they have
+        private const float CustomTooltipDelay = 0.5f;
+
         public AlertPrototype Alert { get; }
 
         /// <summary>
-        /// Total duration of the cooldown in seconds. Null if no duration / cooldown.
+        /// Current cooldown displayed in this slot. Set to null to show no cooldown.
         /// </summary>
-        public int? TotalDuration { get; set; }
+        public (TimeSpan Start, TimeSpan End)? Cooldown
+        {
+            get => _cooldown;
+            set
+            {
+                _cooldown = value;
+                if (SuppliedTooltip is ActionAlertTooltip actionAlertTooltip)
+                {
+                    actionAlertTooltip.Cooldown = value;
+                }
+            }
+        }
+        private (TimeSpan Start, TimeSpan End)? _cooldown;
 
         private short? _severity;
+        private readonly IGameTiming _gameTiming;
         private readonly TextureRect _icon;
         private readonly CooldownGraphic _cooldownGraphic;
-
         private readonly IResourceCache _resourceCache;
 
-
         /// <summary>
         /// Creates an alert control reflecting the indicated alert + state
         /// </summary>
@@ -33,6 +51,9 @@ namespace Content.Client.GameObjects.Components.Mobs
         /// <param name="resourceCache">resourceCache to use to load alert icon textures</param>
         public AlertControl(AlertPrototype alert, short? severity, IResourceCache resourceCache)
         {
+            _gameTiming = IoCManager.Resolve<IGameTiming>();
+            TooltipDelay = CustomTooltipDelay;
+            TooltipSupplier = SupplyTooltip;
             _resourceCache = resourceCache;
             Alert = alert;
             _severity = severity;
@@ -49,6 +70,11 @@ namespace Content.Client.GameObjects.Components.Mobs
 
         }
 
+        private Control SupplyTooltip(Control? sender)
+        {
+            return new ActionAlertTooltip(Alert.Name, Alert.Description) {Cooldown = Cooldown};
+        }
+
         /// <summary>
         /// Change the alert severity, changing the displayed icon
         /// </summary>
@@ -61,33 +87,24 @@ namespace Content.Client.GameObjects.Components.Mobs
             }
         }
 
-        /// <summary>
-        /// Updates the displayed cooldown amount, doing nothing if alertCooldown is null
-        /// </summary>
-        /// <param name="alertCooldown">cooldown start and end</param>
-        /// <param name="curTime">current game time</param>
-        public void UpdateCooldown((TimeSpan Start, TimeSpan End)? alertCooldown, in TimeSpan curTime)
+        protected override void FrameUpdate(FrameEventArgs args)
         {
-            if (!alertCooldown.HasValue)
+            base.FrameUpdate(args);
+            if (!Cooldown.HasValue)
             {
-                _cooldownGraphic.Progress = 0;
                 _cooldownGraphic.Visible = false;
-                TotalDuration = null;
+                _cooldownGraphic.Progress = 0;
+                return;
             }
-            else
-            {
 
-                var start = alertCooldown.Value.Start;
-                var end = alertCooldown.Value.End;
+            var duration = Cooldown.Value.End - Cooldown.Value.Start;
+            var curTime = _gameTiming.CurTime;
+            var length = duration.TotalSeconds;
+            var progress = (curTime - Cooldown.Value.Start).TotalSeconds / length;
+            var ratio = (progress <= 1 ? (1 - progress) : (curTime - Cooldown.Value.End).TotalSeconds * -5);
 
-                var length = (end - start).TotalSeconds;
-                var progress = (curTime - start).TotalSeconds / length;
-                var ratio = (progress <= 1 ? (1 - progress) : (curTime - end).TotalSeconds * -5);
-
-                TotalDuration = (int?) Math.Round(length);
             _cooldownGraphic.Progress = MathHelper.Clamp((float)ratio, -1, 1);
             _cooldownGraphic.Visible = ratio > -1f;
         }
     }
 }
-}

Content.Client/UserInterface/ItemSlotButton.cs

@@ -1,14 +1,19 @@
 using System;
 using Robust.Client.Graphics;
+using Robust.Client.Graphics.Shaders;
 using Robust.Client.UserInterface;
 using Robust.Client.UserInterface.Controls;
 using Robust.Shared.Input;
+using Robust.Shared.IoC;
 using Robust.Shared.Maths;
+using Robust.Shared.Prototypes;
 
 namespace Content.Client.UserInterface
 {
     public class ItemSlotButton : MarginContainer
     {
+        private const string HighlightShader = "SelectionOutlineInrange";
+
         public TextureRect Button { get; }
         public SpriteView SpriteView { get; }
         public SpriteView HoverSpriteView { get; }
@@ -21,9 +26,11 @@ namespace Content.Client.UserInterface
 
         public bool EntityHover => HoverSpriteView.Sprite != null;
         public bool MouseIsHovering = false;
+        private readonly ShaderInstance _highlightShader;
 
         public ItemSlotButton(Texture texture, Texture storageTexture)
         {
+            _highlightShader = IoCManager.Resolve<IPrototypeManager>().Index<ShaderPrototype>(HighlightShader).Instance();
             CustomMinimumSize = (64, 64);
 
             AddChild(Button = new TextureRect
@@ -95,6 +102,20 @@ namespace Content.Client.UserInterface
             }
         }
 
+        public void Highlight(bool on)
+        {
+            // I make no claim that this actually looks good but it's a start.
+            if (on)
+            {
+                Button.ShaderOverride = _highlightShader;
+            }
+            else
+            {
+                Button.ShaderOverride = null;
+            }
+
+        }
+
         private void OnButtonPressed(GUIBoundKeyEventArgs args)
         {
             OnPressed?.Invoke(args);

Content.Client/UserInterface/OptionsMenu.KeyRebind.cs

@@ -150,7 +150,6 @@ namespace Content.Client.UserInterface
                 AddButton(ContentKeyFunctions.ReleasePulledObject, "Release pulled object");
                 AddButton(ContentKeyFunctions.Point, "Point at location");
 
-
                 AddHeader("User Interface");
                 AddButton(ContentKeyFunctions.FocusChat, "Focus chat");
                 AddButton(ContentKeyFunctions.FocusOOC, "Focus chat (OOC)");
@@ -160,6 +159,7 @@ namespace Content.Client.UserInterface
                 AddButton(ContentKeyFunctions.OpenCraftingMenu, "Open crafting menu");
                 AddButton(ContentKeyFunctions.OpenInventoryMenu, "Open inventory");
                 AddButton(ContentKeyFunctions.OpenTutorial, "Open tutorial");
+                AddButton(ContentKeyFunctions.OpenActionsMenu, "Open action menu");
                 AddButton(ContentKeyFunctions.OpenEntitySpawnWindow, "Open entity spawn menu");
                 AddButton(ContentKeyFunctions.OpenSandboxWindow, "Open sandbox menu");
                 AddButton(ContentKeyFunctions.OpenTileSpawnWindow, "Open tile spawn menu");
@@ -169,6 +169,18 @@ namespace Content.Client.UserInterface
                 AddButton(ContentKeyFunctions.TakeScreenshot, "Take screenshot");
                 AddButton(ContentKeyFunctions.TakeScreenshotNoUI, "Take screenshot (without UI)");
 
+                AddHeader("Hotbar");
+                AddButton(ContentKeyFunctions.Hotbar1, "Hotbar slot 1");
+                AddButton(ContentKeyFunctions.Hotbar2, "Hotbar slot 2");
+                AddButton(ContentKeyFunctions.Hotbar3, "Hotbar slot 3");
+                AddButton(ContentKeyFunctions.Hotbar4, "Hotbar slot 4");
+                AddButton(ContentKeyFunctions.Hotbar5, "Hotbar slot 5");
+                AddButton(ContentKeyFunctions.Hotbar6, "Hotbar slot 6");
+                AddButton(ContentKeyFunctions.Hotbar7, "Hotbar slot 7");
+                AddButton(ContentKeyFunctions.Hotbar8, "Hotbar slot 8");
+                AddButton(ContentKeyFunctions.Hotbar9, "Hotbar slot 9");
+                AddButton(ContentKeyFunctions.Hotbar0, "Hotbar slot 0");
+
                 AddHeader("Map Editor");
                 AddButton(EngineKeyFunctions.EditorPlaceObject, "Place object");
                 AddButton(EngineKeyFunctions.EditorCancelPlace, "Cancel placement");

Content.Client/UserInterface/Stylesheets/StyleNano.cs

@@ -1,5 +1,6 @@
 using System.Linq;
 using Content.Client.GameObjects.EntitySystems;
+using Content.Client.UserInterface.Controls;
 using Content.Client.Utility;
 using Robust.Client.Graphics.Drawing;
 using Robust.Client.Interfaces.ResourceManagement;
@@ -15,10 +16,19 @@ namespace Content.Client.UserInterface.Stylesheets
     {
         public const string StyleClassBorderedWindowPanel = "BorderedWindowPanel";
         public const string StyleClassTransparentBorderedWindowPanel = "TransparentBorderedWindowPanel";
+        public const string StyleClassHotbarPanel = "HotbarPanel";
         public const string StyleClassTooltipPanel = "tooltipBox";
         public const string StyleClassTooltipAlertTitle = "tooltipAlertTitle";
         public const string StyleClassTooltipAlertDescription = "tooltipAlertDesc";
         public const string StyleClassTooltipAlertCooldown = "tooltipAlertCooldown";
+        public const string StyleClassTooltipActionTitle = "tooltipActionTitle";
+        public const string StyleClassTooltipActionDescription = "tooltipActionDesc";
+        public const string StyleClassTooltipActionCooldown = "tooltipActionCooldown";
+        public const string StyleClassTooltipActionRequirements = "tooltipActionCooldown";
+        public const string StyleClassHotbarSlotNumber = "hotbarSlotNumber";
+        public const string StyleClassActionSearchBox = "actionSearchBox";
+        public const string StyleClassActionMenuItemRevoked = "actionMenuItemRevoked";
+
 
         public const string StyleClassSliderRed = "Red";
         public const string StyleClassSliderGreen = "Green";
@@ -60,6 +70,8 @@ namespace Content.Client.UserInterface.Stylesheets
             var notoSansItalic12 = resCache.GetFont("/Fonts/NotoSans/NotoSans-Italic.ttf", 12);
             var notoSansBold12 = resCache.GetFont("/Fonts/NotoSans/NotoSans-Bold.ttf", 12);
             var notoSansDisplayBold14 = resCache.GetFont("/Fonts/NotoSansDisplay/NotoSansDisplay-Bold.ttf", 14);
+            var notoSansDisplayBold16 = resCache.GetFont("/Fonts/NotoSansDisplay/NotoSansDisplay-Bold.ttf", 16);
+            var notoSans15 = resCache.GetFont("/Fonts/NotoSans/NotoSans-Regular.ttf", 15);
             var notoSans16 = resCache.GetFont("/Fonts/NotoSans/NotoSans-Regular.ttf", 16);
             var notoSansBold16 = resCache.GetFont("/Fonts/NotoSans/NotoSans-Bold.ttf", 16);
             var notoSansBold18 = resCache.GetFont("/Fonts/NotoSans/NotoSans-Bold.ttf", 18);
@@ -95,6 +107,61 @@ namespace Content.Client.UserInterface.Stylesheets
             };
             borderedTransparentWindowBackground.SetPatchMargin(StyleBox.Margin.All, 2);
 
+            var hotbarBackground = new StyleBoxTexture
+            {
+                Texture = borderedWindowBackgroundTex,
+            };
+            hotbarBackground.SetPatchMargin(StyleBox.Margin.All, 2);
+            hotbarBackground.SetExpandMargin(StyleBox.Margin.All, 4);
+
+            var buttonRectTex = resCache.GetTexture("/Textures/Interface/Nano/light_panel_background_bordered.png");
+            var buttonRect = new StyleBoxTexture(BaseButton)
+            {
+                Texture = buttonRectTex
+            };
+            buttonRect.SetPatchMargin(StyleBox.Margin.All, 2);
+            buttonRect.SetPadding(StyleBox.Margin.All, 2);
+            buttonRect.SetContentMarginOverride(StyleBox.Margin.Vertical, 2);
+            buttonRect.SetContentMarginOverride(StyleBox.Margin.Horizontal, 2);
+
+            var buttonRectHover = new StyleBoxTexture(buttonRect)
+            {
+                Modulate = ButtonColorHovered
+            };
+
+            var buttonRectPressed = new StyleBoxTexture(buttonRect)
+            {
+                Modulate = ButtonColorPressed
+            };
+
+            var buttonRectDisabled = new StyleBoxTexture(buttonRect)
+            {
+                Modulate = ButtonColorDisabled
+            };
+
+            var buttonRectActionMenuItemTex = resCache.GetTexture("/Textures/Interface/Nano/black_panel_light_thin_border.png");
+            var buttonRectActionMenuRevokedItemTex = resCache.GetTexture("/Textures/Interface/Nano/black_panel_red_thin_border.png");
+            var buttonRectActionMenuItem = new StyleBoxTexture(BaseButton)
+            {
+                Texture = buttonRectActionMenuItemTex
+            };
+            buttonRectActionMenuItem.SetPatchMargin(StyleBox.Margin.All, 2);
+            buttonRectActionMenuItem.SetPadding(StyleBox.Margin.All, 2);
+            buttonRectActionMenuItem.SetContentMarginOverride(StyleBox.Margin.Vertical, 2);
+            buttonRectActionMenuItem.SetContentMarginOverride(StyleBox.Margin.Horizontal, 2);
+            var buttonRectActionMenuItemRevoked = new StyleBoxTexture(buttonRectActionMenuItem)
+            {
+                Texture = buttonRectActionMenuRevokedItemTex
+            };
+            var buttonRectActionMenuItemHover = new StyleBoxTexture(buttonRectActionMenuItem)
+            {
+                Modulate = ButtonColorHovered
+            };
+            var buttonRectActionMenuItemPressed = new StyleBoxTexture(buttonRectActionMenuItem)
+            {
+                Modulate = ButtonColorPressed
+            };
+
             var textureInvertedTriangle = resCache.GetTexture("/Textures/Interface/Nano/inverted_triangle.svg.png");
 
             var lineEditTex = resCache.GetTexture("/Textures/Interface/Nano/lineedit.png");
@@ -105,6 +172,14 @@ namespace Content.Client.UserInterface.Stylesheets
             lineEdit.SetPatchMargin(StyleBox.Margin.All, 3);
             lineEdit.SetContentMarginOverride(StyleBox.Margin.Horizontal, 5);
 
+            var actionSearchBoxTex = resCache.GetTexture("/Textures/Interface/Nano/black_panel_dark_thin_border.png");
+            var actionSearchBox = new StyleBoxTexture
+            {
+                Texture = actionSearchBoxTex,
+            };
+            actionSearchBox.SetPatchMargin(StyleBox.Margin.All, 3);
+            actionSearchBox.SetContentMarginOverride(StyleBox.Margin.Horizontal, 5);
+
             var tabContainerPanelTex = resCache.GetTexture("/Textures/Interface/Nano/tabcontainer_panel.png");
             var tabContainerPanel = new StyleBoxTexture
             {
@@ -280,6 +355,12 @@ namespace Content.Client.UserInterface.Stylesheets
                     {
                         new StyleProperty(PanelContainer.StylePropertyPanel, borderedTransparentWindowBackground),
                     }),
+                // Hotbar background
+                new StyleRule(new SelectorElement(typeof(PanelContainer), new[] {StyleClassHotbarPanel}, null, null),
+                    new[]
+                    {
+                        new StyleProperty(PanelContainer.StylePropertyPanel, hotbarBackground),
+                    }),
                 // Window header.
                 new StyleRule(
                     new SelectorElement(typeof(PanelContainer), new[] {SS14Window.StyleClassWindowHeader}, null, null),
@@ -376,6 +457,43 @@ namespace Content.Client.UserInterface.Stylesheets
                         new StyleProperty("font-color", Color.FromHex("#E5E5E581")),
                     }),
 
+                // action slot hotbar buttons
+                new StyleRule(new SelectorElement(typeof(ActionSlot), null, null, new[] {ContainerButton.StylePseudoClassNormal}), new[]
+                {
+                    new StyleProperty(PanelContainer.StylePropertyPanel, buttonRect),
+                }),
+                new StyleRule(new SelectorElement(typeof(ActionSlot), null, null, new[] {ContainerButton.StylePseudoClassHover}), new[]
+                {
+                    new StyleProperty(PanelContainer.StylePropertyPanel, buttonRectHover),
+                }),
+                new StyleRule(new SelectorElement(typeof(ActionSlot), null, null, new[] {ContainerButton.StylePseudoClassPressed}), new[]
+                {
+                    new StyleProperty(PanelContainer.StylePropertyPanel, buttonRectPressed),
+                }),
+                new StyleRule(new SelectorElement(typeof(ActionSlot), null, null, new[] {ContainerButton.StylePseudoClassDisabled}), new[]
+                {
+                    new StyleProperty(PanelContainer.StylePropertyPanel, buttonRectDisabled),
+                }),
+
+                // action menu item buttons
+                new StyleRule(new SelectorElement(typeof(ActionMenuItem), null, null, new[] {ContainerButton.StylePseudoClassNormal}), new[]
+                {
+                    new StyleProperty(ContainerButton.StylePropertyStyleBox, buttonRectActionMenuItem),
+                }),
+                // we don't actually disable the action menu items, only change their style based on the underlying action being revoked
+                new StyleRule(new SelectorElement(typeof(ActionMenuItem), new [] {StyleClassActionMenuItemRevoked}, null, new[] {ContainerButton.StylePseudoClassNormal}), new[]
+                {
+                    new StyleProperty(ContainerButton.StylePropertyStyleBox, buttonRectActionMenuItemRevoked),
+                }),
+                new StyleRule(new SelectorElement(typeof(ActionMenuItem), null, null, new[] {ContainerButton.StylePseudoClassHover}), new[]
+                {
+                    new StyleProperty(ContainerButton.StylePropertyStyleBox, buttonRectActionMenuItemHover),
+                }),
+                new StyleRule(new SelectorElement(typeof(ActionMenuItem), null, null, new[] {ContainerButton.StylePseudoClassPressed}), new[]
+                {
+                    new StyleProperty(ContainerButton.StylePropertyStyleBox, buttonRectActionMenuItemPressed),
+                }),
+
                 // Main menu: Make those buttons bigger.
                 new StyleRule(new SelectorChild(
                     new SelectorElement(typeof(Button), null, "mainMenu", null),
@@ -413,6 +531,13 @@ namespace Content.Client.UserInterface.Stylesheets
                         new StyleProperty("font-color", Color.Gray),
                     }),
 
+                // Action searchbox lineedit
+                new StyleRule(new SelectorElement(typeof(LineEdit), new[] {StyleClassActionSearchBox}, null, null),
+                    new[]
+                    {
+                        new StyleProperty(LineEdit.StylePropertyStyleBox, actionSearchBox),
+                    }),
+
                 // TabContainer
                 new StyleRule(new SelectorElement(typeof(TabContainer), null, null, null),
                     new[]
@@ -531,6 +656,30 @@ namespace Content.Client.UserInterface.Stylesheets
                     new StyleProperty("font", notoSans16)
                 }),
 
+                // action tooltip
+                new StyleRule(new SelectorElement(typeof(RichTextLabel), new[] {StyleClassTooltipActionTitle}, null, null), new[]
+                {
+                    new StyleProperty("font", notoSansBold16)
+                }),
+                new StyleRule(new SelectorElement(typeof(RichTextLabel), new[] {StyleClassTooltipActionDescription}, null, null), new[]
+                {
+                    new StyleProperty("font", notoSans15)
+                }),
+                new StyleRule(new SelectorElement(typeof(RichTextLabel), new[] {StyleClassTooltipActionCooldown}, null, null), new[]
+                {
+                    new StyleProperty("font", notoSans15)
+                }),
+                new StyleRule(new SelectorElement(typeof(RichTextLabel), new[] {StyleClassTooltipActionRequirements}, null, null), new[]
+                {
+                    new StyleProperty("font", notoSans15)
+                }),
+
+                // hotbar slot
+                new StyleRule(new SelectorElement(typeof(RichTextLabel), new[] {StyleClassHotbarSlotNumber}, null, null), new[]
+                {
+                    new StyleProperty("font", notoSansDisplayBold16)
+                }),
+
                 // Entity tooltip
                 new StyleRule(
                     new SelectorElement(typeof(PanelContainer), new[] {ExamineSystem.StyleClassEntityTooltip}, null,

Content.Client/UserInterface/TutorialWindow.cs

@@ -74,6 +74,7 @@ Smart equip from belt: [color=#a4885c]{25}[/color]
 Open inventory: [color=#a4885c]{7}[/color]
 Open character window: [color=#a4885c]{8}[/color]
 Open crafting window: [color=#a4885c]{9}[/color]
+Open action menu: [color=#a4885c]{33}[/color]
 Focus chat: [color=#a4885c]{10}[/color]
 Focus OOC: [color=#a4885c]{26}[/color]
 Focus Admin Chat: [color=#a4885c]{27}[/color]
@@ -94,7 +95,18 @@ Toggle debug overlay: [color=#a4885c]{18}[/color]
 Toggle entity spawner: [color=#a4885c]{19}[/color]
 Toggle tile spawner: [color=#a4885c]{20}[/color]
 Toggle sandbox window: [color=#a4885c]{21}[/color]
-Toggle admin menu [color=#a4885c]{31}[/color]",
+Toggle admin menu [color=#a4885c]{31}[/color]
+Hotbar slot 1: [color=#a4885c]{34}[/color]
+Hotbar slot 2: [color=#a4885c]{35}[/color]
+Hotbar slot 3: [color=#a4885c]{36}[/color]
+Hotbar slot 4: [color=#a4885c]{37}[/color]
+Hotbar slot 5: [color=#a4885c]{38}[/color]
+Hotbar slot 6: [color=#a4885c]{39}[/color]
+Hotbar slot 7: [color=#a4885c]{40}[/color]
+Hotbar slot 8: [color=#a4885c]{41}[/color]
+Hotbar slot 9: [color=#a4885c]{42}[/color]
+Hotbar slot 0: [color=#a4885c]{43}[/color]
+                ",
                 Key(MoveUp), Key(MoveLeft), Key(MoveDown), Key(MoveRight),
                 Key(SwapHands),
                 Key(ActivateItemInHand),
@@ -124,7 +136,18 @@ Toggle admin menu [color=#a4885c]{31}[/color]",
                 Key(TryPullObject),
                 Key(MovePulledObject),
                 Key(OpenAdminMenu),
-                Key(ReleasePulledObject)));
+                Key(ReleasePulledObject),
+                Key(OpenActionsMenu),
+                Key(Hotbar1),
+                Key(Hotbar2),
+                Key(Hotbar3),
+                Key(Hotbar4),
+                Key(Hotbar5),
+                Key(Hotbar6),
+                Key(Hotbar7),
+                Key(Hotbar8),
+                Key(Hotbar9),
+                Key(Hotbar0)));
 
             //Gameplay
             VBox.AddChild(new Label { FontOverride = headerFont, Text = "\nGameplay" });

Content.Client/Utility/DragDropHelper.cs

@@ -0,0 +1,172 @@
+using Robust.Client.Interfaces.Input;
+using Robust.Shared.IoC;
+using Robust.Shared.Maths;
+
+namespace Content.Client.Utility
+{
+    /// <summary>
+    /// Helper for implementing drag and drop interactions.
+    ///
+    /// The basic flow for a drag drop interaction as per this helper is:
+    /// 1. User presses mouse down on something (using class should communicate this to helper by calling MouseDown()).
+    /// 2. User continues to hold the mouse down and moves the mouse outside of the defined
+    ///    deadzone. OnBeginDrag is invoked to see if a drag should be initiated. If so, initiates a drag.
+    ///    If user didn't move the mouse beyond the deadzone the drag is not initiated (OnEndDrag invoked).
+    /// 3. Every Update/FrameUpdate, OnContinueDrag is invoked.
+    /// 4. User lifts mouse up. This is not handled by DragDropHelper. The using class of the helper should
+    ///     do whatever they want and then end the drag by calling EndDrag() (which invokes OnEndDrag).
+    ///
+    /// If for any reason the drag is ended, OnEndDrag is invoked.
+    /// </summary>
+    /// <typeparam name="T">thing being dragged and dropped</typeparam>
+    public class DragDropHelper<T>
+    {
+        private const float DefaultDragDeadzone = 2f;
+
+        private readonly IInputManager _inputManager;
+
+        private readonly OnBeginDrag _onBeginDrag;
+        private readonly OnEndDrag _onEndDrag;
+        private readonly OnContinueDrag _onContinueDrag;
+        private readonly float _deadzone;
+
+        /// <summary>
+        /// Convenience method, current mouse screen position as provided by inputmanager.
+        /// </summary>
+        public Vector2 MouseScreenPosition => _inputManager.MouseScreenPosition;
+
+        /// <summary>
+        /// True if initiated a drag and currently dragging something.
+        /// I.e. this will be false if we've just had a mousedown over something but the mouse
+        /// has not moved outside of the drag deadzone.
+        /// </summary>
+        public bool IsDragging => _state == DragState.Dragging;
+
+        /// <summary>
+        /// Current thing being dragged or which mouse button is being held down on.
+        /// </summary>
+        public T Dragged { get; private set; }
+
+        // screen pos where the mouse down began for the drag
+        private Vector2 _mouseDownScreenPos;
+        private DragState _state = DragState.NotDragging;
+
+        private enum DragState : byte
+        {
+            NotDragging,
+            // not dragging yet, waiting to see
+            // if they hold for long enough
+            MouseDown,
+            // currently dragging something
+            Dragging,
+        }
+
+        /// <param name="onBeginDrag"><see cref="OnBeginDrag"/></param>
+        /// <param name="onContinueDrag"><see cref="OnContinueDrag"/></param>
+        /// <param name="onEndDrag"><see cref="OnEndDrag"/></param>
+        /// <param name="deadzone">drag will be triggered when mouse leaves
+        ///     this deadzone around the mousedown position</param>
+        public DragDropHelper(OnBeginDrag onBeginDrag, OnContinueDrag onContinueDrag,
+            OnEndDrag onEndDrag, float deadzone = DefaultDragDeadzone)
+        {
+            _deadzone = deadzone;
+            _inputManager = IoCManager.Resolve<IInputManager>();
+            _onBeginDrag = onBeginDrag;
+            _onEndDrag = onEndDrag;
+            _onContinueDrag = onContinueDrag;
+        }
+
+        /// <summary>
+        /// Tell the helper that the mouse button was pressed down on
+        /// a target, thus a drag has the possibility to begin for this target.
+        /// Assumes current mouse screen position is the location the mouse was clicked.
+        ///
+        /// EndDrag should be called when the drag is done.
+        /// </summary>
+        public void MouseDown(T target)
+        {
+            if (_state != DragState.NotDragging)
+            {
+                EndDrag();
+            }
+
+            Dragged = target;
+            _state = DragState.MouseDown;
+            _mouseDownScreenPos = _inputManager.MouseScreenPosition;
+        }
+
+        /// <summary>
+        /// Stop the current drag / drop operation no matter what state it is in.
+        /// </summary>
+        public void EndDrag()
+        {
+            Dragged = default;
+            _state = DragState.NotDragging;
+            _onEndDrag.Invoke();
+        }
+
+        private void StartDragging()
+        {
+            if (_onBeginDrag.Invoke())
+            {
+                _state = DragState.Dragging;
+            }
+            else
+            {
+                EndDrag();
+            }
+        }
+
+        /// <summary>
+        /// Should be invoked by using class every FrameUpdate or Update.
+        /// </summary>
+        public void Update(float frameTime)
+        {
+            switch (_state)
+            {
+                // check if dragging should begin
+                case DragState.MouseDown:
+                {
+                    var screenPos = _inputManager.MouseScreenPosition;
+                    if ((_mouseDownScreenPos - screenPos).Length > _deadzone)
+                    {
+                        StartDragging();
+                    }
+
+                    break;
+                }
+                case DragState.Dragging:
+                {
+                    if (!_onContinueDrag.Invoke(frameTime))
+                    {
+                        EndDrag();
+                    }
+
+                    break;
+                }
+            }
+        }
+    }
+
+    /// <summary>
+    /// Invoked when a drag is confirmed and going to be initiated. Implementation should
+    /// typically set the drag shadow texture based on the target.
+    /// </summary>
+    /// <returns>true if drag should begin, false to end.</returns>
+    public delegate bool OnBeginDrag();
+
+    /// <summary>
+    /// Invoked every frame when drag is ongoing. Typically implementation should
+    /// make the drag shadow follow the mouse position.
+    /// </summary>
+    /// <returns>true if drag should continue, false to end.</returns>
+    public delegate bool OnContinueDrag(float frameTime);
+
+    /// <summary>
+    /// invoked when
+    /// the drag drop is ending for any reason. This
+    /// should typically just clear the drag shadow.
+    /// </summary>
+    public delegate void OnEndDrag();
+
+}

Content.IntegrationTests/Tests/GameObjects/Components/Mobs/ActionsComponentTests.cs

@@ -0,0 +1,186 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+using Content.Client.GameObjects.Components.Mobs;
+using Content.Client.UserInterface;
+using Content.Client.UserInterface.Controls;
+using Content.Server.GameObjects.Components.Mobs;
+using Content.Shared.Actions;
+using Content.Shared.Alert;
+using Content.Shared.GameObjects.Components.Mobs;
+using Content.Shared.GameObjects.EntitySystems;
+using NUnit.Framework;
+using Robust.Client.Interfaces.UserInterface;
+using Robust.Client.Player;
+
+namespace Content.IntegrationTests.Tests.GameObjects.Components.Mobs
+{
+    [TestFixture]
+    [TestOf(typeof(SharedActionsComponent))]
+    [TestOf(typeof(ClientActionsComponent))]
+    [TestOf(typeof(ServerActionsComponent))]
+    public class ActionsComponentTests : ContentIntegrationTest
+    {
+        [Test]
+        public async Task GrantsAndRevokesActionsTest()
+        {
+            var (client, server) = await StartConnectedServerClientPair();
+
+            await server.WaitIdleAsync();
+            await client.WaitIdleAsync();
+
+            var serverPlayerManager = server.ResolveDependency<Robust.Server.Interfaces.Player.IPlayerManager>();
+            var innateActions = new List<ActionType>();
+
+            await server.WaitAssertion(() =>
+            {
+                var player = serverPlayerManager.GetAllPlayers().Single();
+                var playerEnt = player.AttachedEntity;
+                var actionsComponent = playerEnt.GetComponent<ServerActionsComponent>();
+
+                // player should begin with their innate actions granted
+                innateActions.AddRange(actionsComponent.InnateActions);
+                foreach (var innateAction in actionsComponent.InnateActions)
+                {
+                    Assert.That(actionsComponent.TryGetActionState(innateAction, out var innateState));
+                    Assert.That(innateState.Enabled);
+                }
+
+                actionsComponent.Grant(ActionType.DebugInstant);
+                Assert.That(actionsComponent.TryGetActionState(ActionType.HumanScream, out var state) && state.Enabled);
+            });
+
+            // check that client has the actions
+            await server.WaitRunTicks(5);
+            await client.WaitRunTicks(5);
+
+            var clientPlayerMgr = client.ResolveDependency<IPlayerManager>();
+            var clientUIMgr = client.ResolveDependency<IUserInterfaceManager>();
+            var expectedOrder = new List<ActionType>();
+            await client.WaitAssertion(() =>
+            {
+
+                var local = clientPlayerMgr.LocalPlayer;
+                var controlled = local.ControlledEntity;
+                var actionsComponent = controlled.GetComponent<ClientActionsComponent>();
+
+                // we should have our innate actions and debug1.
+                foreach (var innateAction in innateActions)
+                {
+                    Assert.That(actionsComponent.TryGetActionState(innateAction, out var innateState));
+                    Assert.That(innateState.Enabled);
+                }
+                Assert.That(actionsComponent.TryGetActionState(ActionType.DebugInstant, out var state) && state.Enabled);
+
+                // innate actions should've auto-populated into our slots (in non-deterministic order),
+                // but debug1 should be in the last slot
+                var actionsUI =
+                    clientUIMgr.StateRoot.Children.FirstOrDefault(c => c is ActionsUI) as ActionsUI;
+                Assert.That(actionsUI, Is.Not.Null);
+
+                var expectedInnate = new HashSet<ActionType>(innateActions);
+                var expectEmpty = false;
+                expectedOrder.Clear();
+                foreach (var slot in actionsUI.Slots)
+                {
+                    if (expectEmpty)
+                    {
+                        Assert.That(slot.HasAssignment, Is.False);
+                        Assert.That(slot.Item, Is.Null);
+                        Assert.That(slot.Action, Is.Null);
+                        Assert.That(slot.ActionEnabled, Is.False);
+                        continue;
+                    }
+                    Assert.That(slot.HasAssignment);
+                    // all the actions we gave so far are not tied to an item
+                    Assert.That(slot.Item, Is.Null);
+                    Assert.That(slot.Action, Is.Not.Null);
+                    Assert.That(slot.ActionEnabled);
+                    var asAction = slot.Action as ActionPrototype;
+                    Assert.That(asAction, Is.Not.Null);
+                    expectedOrder.Add(asAction.ActionType);
+
+                    if (expectedInnate.Count != 0)
+                    {
+                        Assert.That(expectedInnate.Remove(asAction.ActionType));
+                    }
+                    else
+                    {
+                        Assert.That(asAction.ActionType, Is.EqualTo(ActionType.DebugInstant));
+                        Assert.That(slot.Cooldown, Is.Null);
+                        expectEmpty = true;
+                    }
+                }
+            });
+
+            // now revoke the action and check that the client sees it as revoked
+            await server.WaitAssertion(() =>
+            {
+                var player = serverPlayerManager.GetAllPlayers().Single();
+                var playerEnt = player.AttachedEntity;
+                var actionsComponent = playerEnt.GetComponent<ServerActionsComponent>();
+                actionsComponent.Revoke(ActionType.DebugInstant);
+            });
+
+            await server.WaitRunTicks(5);
+            await client.WaitRunTicks(5);
+
+            await client.WaitAssertion(() =>
+            {
+
+                var local = clientPlayerMgr.LocalPlayer;
+                var controlled = local.ControlledEntity;
+                var actionsComponent = controlled.GetComponent<ClientActionsComponent>();
+
+                // we should have our innate actions, but debug1 should be revoked
+                foreach (var innateAction in innateActions)
+                {
+                    Assert.That(actionsComponent.TryGetActionState(innateAction, out var innateState));
+                    Assert.That(innateState.Enabled);
+                }
+                Assert.That(actionsComponent.TryGetActionState(ActionType.DebugInstant, out var state), Is.False);
+
+                // all actions should be in the same order as before, but the slot with DebugInstant should appear
+                // disabled.
+                var actionsUI =
+                    clientUIMgr.StateRoot.Children.FirstOrDefault(c => c is ActionsUI) as ActionsUI;
+                Assert.That(actionsUI, Is.Not.Null);
+
+                var idx = 0;
+                foreach (var slot in actionsUI.Slots)
+                {
+                    if (idx < expectedOrder.Count)
+                    {
+                        var expected = expectedOrder[idx++];
+                        Assert.That(slot.HasAssignment);
+                        // all the actions we gave so far are not tied to an item
+                        Assert.That(slot.Item, Is.Null);
+                        Assert.That(slot.Action, Is.Not.Null);
+                        var asAction = slot.Action as ActionPrototype;
+                        Assert.That(asAction, Is.Not.Null);
+
+                        if (asAction.ActionType == ActionType.DebugInstant)
+                        {
+                            Assert.That(slot.ActionEnabled, Is.False);
+                        }
+                        else
+                        {
+                            Assert.That(slot.ActionEnabled);
+                        }
+                    }
+                    else
+                    {
+                        Assert.That(slot.HasAssignment, Is.False);
+                        Assert.That(slot.Item, Is.Null);
+                        Assert.That(slot.Action, Is.Null);
+                        Assert.That(slot.ActionEnabled, Is.False);
+                        continue;
+                    }
+                }
+            });
+        }
+
+    }
+}

Content.IntegrationTests/Tests/GameObjects/Components/Mobs/AlertsComponentTests.cs

@@ -2,14 +2,12 @@
 using System.Threading.Tasks;
 using Content.Client.GameObjects.Components.Mobs;
 using Content.Client.UserInterface;
+using Content.Client.UserInterface.Controls;
 using Content.Server.GameObjects.Components.Mobs;
 using Content.Shared.Alert;
 using NUnit.Framework;
 using Robust.Client.Interfaces.UserInterface;
 using Robust.Client.Player;
-using Robust.Shared.Interfaces.Map;
-using Robust.Shared.IoC;
-using Robust.Shared.Map;
 
 namespace Content.IntegrationTests.Tests.GameObjects.Components.Mobs
 {

Content.IntegrationTests/Tests/Gravity/WeightlessStatusTests.cs

@@ -25,7 +25,7 @@ namespace Content.IntegrationTests.Tests.Gravity
   name: HumanDummy
   id: HumanDummy
   components:
-  - type: AlertsUI
+  - type: Alerts
 ";
         [Test]
         public async Task WeightlessStatusTest()

Content.Server/Actions/DebugInstant.cs

@@ -0,0 +1,39 @@
+using Content.Server.Utility;
+using Content.Shared.Actions;
+using Content.Shared.Utility;
+using JetBrains.Annotations;
+using Robust.Shared.Serialization;
+
+namespace Content.Server.Actions
+{
+    /// <summary>
+    /// Just shows a popup message.asd
+    /// </summary>
+    [UsedImplicitly]
+    public class DebugInstant : IInstantAction, IInstantItemAction
+    {
+        public string Message { get; private set; }
+        public float Cooldown { get; private set; }
+
+        public void ExposeData(ObjectSerializer serializer)
+        {
+            serializer.DataField(this, x => x.Message, "message", "Instant action used.");
+            serializer.DataField(this, x => x.Cooldown, "cooldown", 0);
+        }
+
+        public void DoInstantAction(InstantItemActionEventArgs args)
+        {
+            args.Performer.PopupMessageEveryone(Message);
+            if (Cooldown > 0)
+            {
+                args.ItemActions.Cooldown(args.ActionType, Cooldowns.SecondsFromNow(Cooldown));
+            }
+        }
+
+        public void DoInstantAction(InstantActionEventArgs args)
+        {
+            args.Performer.PopupMessageEveryone(Message);
+            args.PerformerActions.Cooldown(args.ActionType, Cooldowns.SecondsFromNow(Cooldown));
+        }
+    }
+}

Content.Server/Actions/DebugTargetEntity.cs

@@ -0,0 +1,28 @@
+using Content.Server.Utility;
+using Content.Shared.Actions;
+using JetBrains.Annotations;
+using Robust.Shared.Serialization;
+
+namespace Content.Server.Actions
+{
+    [UsedImplicitly]
+    public class DebugTargetEntity : ITargetEntityAction, ITargetEntityItemAction
+    {
+
+        public void ExposeData(ObjectSerializer serializer)
+        {
+        }
+
+        public void DoTargetEntityAction(TargetEntityItemActionEventArgs args)
+        {
+            args.Performer.PopupMessageEveryone(args.Item.Name + ": Clicked " +
+                                                args.Target.Name);
+        }
+
+        public void DoTargetEntityAction(TargetEntityActionEventArgs args)
+        {
+            args.Performer.PopupMessageEveryone("Clicked " +
+                                                args.Target.Name);
+        }
+    }
+}

Content.Server/Actions/DebugTargetPoint.cs

@@ -0,0 +1,29 @@
+using Content.Server.Utility;
+using Content.Shared.Actions;
+using JetBrains.Annotations;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Serialization;
+
+namespace Content.Server.Actions
+{
+    [UsedImplicitly]
+    public class DebugTargetPoint : ITargetPointAction, ITargetPointItemAction
+    {
+        public void ExposeData(ObjectSerializer serializer)
+        {
+        }
+
+        public void DoTargetPointAction(TargetPointItemActionEventArgs args)
+        {
+            args.Performer.PopupMessageEveryone(args.Item.Name + ": Clicked local position " +
+                                                args.Target);
+        }
+
+        public void DoTargetPointAction(TargetPointActionEventArgs args)
+        {
+            args.Performer.PopupMessageEveryone("Clicked local position " +
+                                                args.Target);
+        }
+    }
+}

Content.Server/Actions/DebugToggle.cs

@@ -0,0 +1,48 @@
+using Content.Server.Utility;
+using Content.Shared.Actions;
+using JetBrains.Annotations;
+using Robust.Shared.Serialization;
+
+namespace Content.Server.Actions
+{
+    [UsedImplicitly]
+    public class DebugToggle : IToggleAction, IToggleItemAction
+    {
+        public string MessageOn { get; private set; }
+        public string MessageOff { get; private set; }
+
+        public void ExposeData(ObjectSerializer serializer)
+        {
+            serializer.DataField(this, x => x.MessageOn, "messageOn", "on!");
+            serializer.DataField(this, x => x.MessageOff, "messageOff", "off!");
+        }
+
+        public bool DoToggleAction(ToggleItemActionEventArgs args)
+        {
+            if (args.ToggledOn)
+            {
+                args.Performer.PopupMessageEveryone(args.Item.Name + ": " + MessageOn);
+            }
+            else
+            {
+                args.Performer.PopupMessageEveryone(args.Item.Name + ": " +MessageOff);
+            }
+
+            return true;
+        }
+
+        public bool DoToggleAction(ToggleActionEventArgs args)
+        {
+            if (args.ToggledOn)
+            {
+                args.Performer.PopupMessageEveryone(MessageOn);
+            }
+            else
+            {
+                args.Performer.PopupMessageEveryone(MessageOff);
+            }
+
+            return true;
+        }
+    }
+}

Content.Server/Actions/ScreamAction.cs

@@ -0,0 +1,82 @@
+using System;
+using System.Collections.Generic;
+using Content.Server.GameObjects.Components.Mobs;
+using Content.Shared.Actions;
+using Content.Shared.Audio;
+using Content.Shared.GameObjects.Components.Mobs;
+using Content.Shared.GameObjects.EntitySystems;
+using Content.Shared.Preferences;
+using Content.Shared.Utility;
+using JetBrains.Annotations;
+using Robust.Server.GameObjects.EntitySystems;
+using Robust.Shared.Audio;
+using Robust.Shared.GameObjects.Systems;
+using Robust.Shared.Interfaces.Random;
+using Robust.Shared.IoC;
+using Robust.Shared.Random;
+using Robust.Shared.Serialization;
+
+namespace Content.Server.Actions
+{
+    [UsedImplicitly]
+    public class ScreamAction : IInstantAction
+    {
+        private const float Variation = 0.125f;
+        private const float Volume = 4f;
+
+        private List<string> _male;
+        private List<string> _female;
+        private string _wilhelm;
+        /// seconds
+        private float _cooldown;
+
+        private IRobustRandom _random;
+
+        public ScreamAction()
+        {
+            _random = IoCManager.Resolve<IRobustRandom>();
+        }
+
+        public void ExposeData(ObjectSerializer serializer)
+        {
+            serializer.DataField(ref _male, "male", null);
+            serializer.DataField(ref _female, "female", null);
+            serializer.DataField(ref _wilhelm, "wilhelm", null);
+            serializer.DataField(ref _cooldown, "cooldown", 10);
+        }
+
+        public void DoInstantAction(InstantActionEventArgs args)
+        {
+            if (!ActionBlockerSystem.CanSpeak(args.Performer)) return;
+            if (!args.Performer.TryGetComponent<HumanoidAppearanceComponent>(out var humanoid)) return;
+            if (!args.Performer.TryGetComponent<SharedActionsComponent>(out var actions)) return;
+
+            if (_random.Prob(.01f) && !string.IsNullOrWhiteSpace(_wilhelm))
+            {
+                EntitySystem.Get<AudioSystem>().PlayFromEntity(_wilhelm, args.Performer, AudioParams.Default.WithVolume(Volume));
+            }
+            else
+            {
+                switch (humanoid.Sex)
+                {
+                    case Sex.Male:
+                        if (_male == null) break;
+                        EntitySystem.Get<AudioSystem>().PlayFromEntity(_random.Pick(_male), args.Performer,
+                            AudioHelpers.WithVariation(Variation).WithVolume(Volume));
+                        break;
+                    case Sex.Female:
+                        if (_female == null) break;
+                        EntitySystem.Get<AudioSystem>().PlayFromEntity(_random.Pick(_female), args.Performer,
+                            AudioHelpers.WithVariation(Variation).WithVolume(Volume));
+                        break;
+                    default:
+                        throw new ArgumentOutOfRangeException();
+                }
+            }
+
+
+
+            actions.Cooldown(args.ActionType, Cooldowns.SecondsFromNow(_cooldown));
+        }
+    }
+}

Content.Server/Alert/Click/ResistFire.cs

@@ -0,0 +1,24 @@
+using Content.Server.GameObjects.Components.Atmos;
+ using Content.Shared.Alert;
+ using JetBrains.Annotations;
+ using Robust.Shared.Serialization;
+
+namespace Content.Server.Alert.Click
+{
+    /// <summary>
+    /// Resist fire
+    /// </summary>
+    [UsedImplicitly]
+    public class ResistFire : IAlertClick
+    {
+        public void ExposeData(ObjectSerializer serializer) { }
+
+        public void AlertClicked(ClickAlertEventArgs args)
+        {
+            if (args.Player.TryGetComponent(out FlammableComponent flammable))
+            {
+                flammable.Resist();
+            }
+        }
+    }
+}

Content.Server/Alert/Click/StopPiloting.cs

@@ -0,0 +1,24 @@
+using Content.Server.GameObjects.Components.Movement;
+ using Content.Shared.Alert;
+ using JetBrains.Annotations;
+ using Robust.Shared.Serialization;
+
+namespace Content.Server.Alert.Click
+{
+    /// <summary>
+    /// Stop piloting shuttle
+    /// </summary>
+    [UsedImplicitly]
+    public class StopPiloting : IAlertClick
+    {
+        public void ExposeData(ObjectSerializer serializer) { }
+
+        public void AlertClicked(ClickAlertEventArgs args)
+        {
+            if (args.Player.TryGetComponent(out ShuttleControllerComponent controller))
+            {
+                controller.RemoveController();
+            }
+        }
+    }
+}

Content.Server/Alert/Click/StopPulling.cs

@@ -0,0 +1,27 @@
+using Content.Shared.Alert;
+ using Content.Shared.GameObjects.Components.Pulling;
+ using Content.Shared.GameObjects.EntitySystems;
+ using JetBrains.Annotations;
+ using Robust.Shared.GameObjects.Systems;
+ using Robust.Shared.Serialization;
+
+namespace Content.Server.Alert.Click
+{
+    /// <summary>
+    /// Stop pulling something
+    /// </summary>
+    [UsedImplicitly]
+    public class StopPulling : IAlertClick
+    {
+        public void ExposeData(ObjectSerializer serializer) { }
+
+        public void AlertClicked(ClickAlertEventArgs args)
+        {
+            EntitySystem
+                .Get<SharedPullingSystem>()
+                .GetPulled(args.Player)?
+                .GetComponentOrNull<SharedPullableComponent>()?
+                .TryStopPull();
+        }
+    }
+}

Content.Server/Alert/Click/Unbuckle.cs

@@ -0,0 +1,24 @@
+using Content.Server.GameObjects.Components.Buckle;
+using Content.Shared.Alert;
+using Robust.Shared.Serialization;
+using JetBrains.Annotations;
+
+namespace Content.Server.Alert.Click
+{
+    /// <summary>
+    /// Unbuckles if player is currently buckled.
+    /// </summary>
+	[UsedImplicitly]
+    public class Unbuckle : IAlertClick
+    {
+        public void ExposeData(ObjectSerializer serializer) { }
+
+        public void AlertClicked(ClickAlertEventArgs args)
+        {
+            if (args.Player.TryGetComponent(out BuckleComponent buckle))
+            {
+                buckle.TryUnbuckle(args.Player);
+            }
+        }
+    }
+}

Content.Server/Commands/Actions/CooldownAction.cs

@@ -0,0 +1,65 @@
+#nullable enable
+using System;
+using Content.Server.Administration;
+using Content.Server.GameObjects.Components.Mobs;
+using Content.Shared.Actions;
+using Content.Shared.Administration;
+using Robust.Server.Interfaces.Console;
+using Robust.Server.Interfaces.Player;
+using Robust.Shared.Interfaces.Timing;
+using Robust.Shared.IoC;
+
+namespace Content.Server.Commands.Actions
+{
+    [AdminCommand(AdminFlags.Debug)]
+    public sealed class CooldownAction : IClientCommand
+    {
+        public string Command => "coolaction";
+        public string Description => "Sets a cooldown on an action for a player, defaulting to current player";
+        public string Help => "coolaction <actionType> <seconds> <name or userID, omit for current player>";
+
+        public void Execute(IConsoleShell shell, IPlayerSession? player, string[] args)
+        {
+            if (player == null) return;
+            var attachedEntity = player.AttachedEntity;
+            if (args.Length > 2)
+            {
+                var target = args[2];
+                if (!CommandUtils.TryGetAttachedEntityByUsernameOrId(shell, target, player, out attachedEntity)) return;
+            }
+
+            if (attachedEntity == null) return;
+            if (!attachedEntity.TryGetComponent(out ServerActionsComponent? actionsComponent))
+            {
+                shell.SendText(player, "user has no actions component");
+                return;
+            }
+
+            var actionTypeRaw = args[0];
+            if (!Enum.TryParse<ActionType>(actionTypeRaw, out var actionType))
+            {
+                shell.SendText(player, "unrecognized ActionType enum value, please" +
+                                       " ensure you used correct casing: " + actionTypeRaw);
+                return;
+            }
+            var actionMgr = IoCManager.Resolve<ActionManager>();
+
+            if (!actionMgr.TryGet(actionType, out var action))
+            {
+                shell.SendText(player, "unrecognized actionType " + actionType);
+                return;
+            }
+
+            var cooldownStart = IoCManager.Resolve<IGameTiming>().CurTime;
+            if (!uint.TryParse(args[1], out var seconds))
+            {
+                shell.SendText(player, "cannot parse seconds: " + args[1]);
+                return;
+            }
+
+            var cooldownEnd = cooldownStart.Add(TimeSpan.FromSeconds(seconds));
+
+            actionsComponent.Cooldown(action.ActionType, (cooldownStart, cooldownEnd));
+        }
+    }
+}

Content.Server/Commands/Actions/GrantAction.cs

@@ -0,0 +1,52 @@
+#nullable enable
+using System;
+using Content.Server.Administration;
+using Content.Server.GameObjects.Components.Mobs;
+using Content.Shared.Actions;
+using Content.Shared.Administration;
+using Robust.Server.Interfaces.Console;
+using Robust.Server.Interfaces.Player;
+using Robust.Shared.IoC;
+
+namespace Content.Server.Commands.Actions
+{
+    [AdminCommand(AdminFlags.Debug)]
+    public sealed class GrantAction : IClientCommand
+    {
+        public string Command => "grantaction";
+        public string Description => "Grants an action to a player, defaulting to current player";
+        public string Help => "grantaction <actionType> <name or userID, omit for current player>";
+        public void Execute(IConsoleShell shell, IPlayerSession? player, string[] args)
+        {
+            if (player == null) return;
+            var attachedEntity = player.AttachedEntity;
+            if (args.Length > 1)
+            {
+                var target = args[1];
+                if (!Commands.CommandUtils.TryGetAttachedEntityByUsernameOrId(shell, target, player, out attachedEntity)) return;
+            }
+
+            if (attachedEntity == null) return;
+            if (!attachedEntity.TryGetComponent(out ServerActionsComponent? actionsComponent))
+            {
+                shell.SendText(player, "user has no actions component");
+                return;
+            }
+
+            var actionTypeRaw = args[0];
+            if (!Enum.TryParse<ActionType>(actionTypeRaw, out var actionType))
+            {
+                shell.SendText(player, "unrecognized ActionType enum value, please" +
+                                       " ensure you used correct casing: " + actionTypeRaw);
+                return;
+            }
+            var actionMgr = IoCManager.Resolve<ActionManager>();
+            if (!actionMgr.TryGet(actionType, out var action))
+            {
+                shell.SendText(player, "unrecognized actionType " + actionType);
+                return;
+            }
+            actionsComponent.Grant(action.ActionType);
+        }
+    }
+}

Content.Server/Commands/Actions/RevokeAction.cs

@@ -0,0 +1,53 @@
+#nullable enable
+using System;
+using Content.Server.Administration;
+using Content.Server.GameObjects.Components.Mobs;
+using Content.Shared.Actions;
+using Content.Shared.Administration;
+using Robust.Server.Interfaces.Console;
+using Robust.Server.Interfaces.Player;
+using Robust.Shared.IoC;
+
+namespace Content.Server.Commands.Actions
+{
+    [AdminCommand(AdminFlags.Debug)]
+    public sealed class RevokeAction : IClientCommand
+    {
+        public string Command => "revokeaction";
+        public string Description => "Revokes an action from a player, defaulting to current player";
+        public string Help => "revokeaction <actionType> <name or userID, omit for current player>";
+
+        public void Execute(IConsoleShell shell, IPlayerSession? player, string[] args)
+        {
+            if (player == null) return;
+            var attachedEntity = player.AttachedEntity;
+            if (args.Length > 1)
+            {
+                var target = args[1];
+                if (!CommandUtils.TryGetAttachedEntityByUsernameOrId(shell, target, player, out attachedEntity)) return;
+            }
+            if (attachedEntity == null) return;
+            if (!attachedEntity.TryGetComponent(out ServerActionsComponent? actionsComponent))
+            {
+                shell.SendText(player, "user has no actions component");
+                return;
+            }
+
+            var actionTypeRaw = args[0];
+            if (!Enum.TryParse<ActionType>(actionTypeRaw, out var actionType))
+            {
+                shell.SendText(player, "unrecognized ActionType enum value, please" +
+                                       " ensure you used correct casing: " + actionTypeRaw);
+                return;
+            }
+            var actionMgr = IoCManager.Resolve<ActionManager>();
+            if (!actionMgr.TryGet(actionType, out var action))
+            {
+                shell.SendText(player, "unrecognized actionType " + actionType);
+                return;
+            }
+
+            actionsComponent.Revoke(action.ActionType);
+        }
+    }
+}

Content.Server/Commands/Alerts/ClearAlert.cs

@@ -19,22 +19,20 @@ namespace Content.Server.Commands.Alerts
 
         public void Execute(IConsoleShell shell, IPlayerSession? player, string[] args)
         {
-            var attachedEntity = player?.AttachedEntity;
-
-            if (attachedEntity == null)
+            if (player?.AttachedEntity == null)
             {
                 shell.SendText(player, "You don't have an entity.");
                 return;
             }
 
+            var attachedEntity = player.AttachedEntity;
+
             if (args.Length > 1)
             {
                 var target = args[1];
                 if (!CommandUtils.TryGetAttachedEntityByUsernameOrId(shell, target, player, out attachedEntity)) return;
             }
 
-            if (!CommandUtils.ValidateAttachedEntity(shell, player, attachedEntity)) return;
-
             if (!attachedEntity.TryGetComponent(out ServerAlertsComponent? alertsComponent))
             {
                 shell.SendText(player, "user has no alerts component");

Content.Server/Commands/Alerts/ShowAlert.cs

@@ -39,9 +39,6 @@ namespace Content.Server.Commands.Alerts
                 if (!CommandUtils.TryGetAttachedEntityByUsernameOrId(shell, target, player, out attachedEntity)) return;
             }
 
-            if (!CommandUtils.ValidateAttachedEntity(shell, player, attachedEntity))
-                return;
-
             if (!attachedEntity.TryGetComponent(out ServerAlertsComponent? alertsComponent))
             {
                 shell.SendText(player, "user has no alerts component");

Content.Server/Commands/CommandUtils.cs

@@ -1,4 +1,6 @@
-using System;
+#nullable enable
+using System;
+using System.Diagnostics.CodeAnalysis;
 using Robust.Server.Interfaces.Console;
 using Robust.Server.Interfaces.Player;
 using Robust.Shared.Interfaces.GameObjects;
@@ -17,7 +19,7 @@ namespace Content.Server.Commands
         /// sending a failure to the performer if unable to.
         /// </summary>
         public static bool TryGetSessionByUsernameOrId(IConsoleShell shell,
-            string usernameOrId, IPlayerSession performer, out IPlayerSession session)
+            string usernameOrId, IPlayerSession performer, [NotNullWhen(true)] out IPlayerSession? session)
         {
             var plyMgr = IoCManager.Resolve<IPlayerManager>();
             if (plyMgr.TryGetSessionByUsername(usernameOrId, out session)) return true;
@@ -37,7 +39,7 @@ namespace Content.Server.Commands
         /// sending a failure to the performer if unable to.
         /// </summary>
         public static bool TryGetAttachedEntityByUsernameOrId(IConsoleShell shell,
-            string usernameOrId, IPlayerSession performer, out IEntity attachedEntity)
+            string usernameOrId, IPlayerSession performer, [NotNullWhen(true)]  out IEntity? attachedEntity)
         {
             attachedEntity = null;
             if (!TryGetSessionByUsernameOrId(shell, usernameOrId, performer, out var session)) return false;
@@ -50,17 +52,5 @@ namespace Content.Server.Commands
             attachedEntity = session.AttachedEntity;
             return true;
         }
-
-        /// <summary>
-        /// Checks if attached entity is null, returning false and sending a message
-        /// to performer if not.
-        /// </summary>
-        public static bool ValidateAttachedEntity(IConsoleShell shell, IPlayerSession performer, IEntity attachedEntity)
-        {
-            if (attachedEntity != null) return true;
-            shell.SendText(performer, "User has no attached entity.");
-            return false;
-        }
-
     }
 }

Content.Server/EntryPoint.cs

@@ -10,6 +10,7 @@ using Content.Server.Interfaces.Chat;
 using Content.Server.Interfaces.GameTicking;
 using Content.Server.Interfaces.PDA;
 using Content.Server.Sandbox;
+using Content.Shared.Actions;
 using Content.Shared.Kitchen;
 using Content.Shared.Alert;
 using Robust.Server.Interfaces.Player;
@@ -81,6 +82,7 @@ namespace Content.Server
             _gameTicker.Initialize();
             IoCManager.Resolve<RecipeManager>().Initialize();
             IoCManager.Resolve<AlertManager>().Initialize();
+            IoCManager.Resolve<ActionManager>().Initialize();
             IoCManager.Resolve<BlackboardManager>().Initialize();
             IoCManager.Resolve<ConsiderationsManager>().Initialize();
             IoCManager.Resolve<IPDAUplinkManager>().Initialize();

Content.Server/GameObjects/Components/Atmos/FlammableComponent.cs

@@ -100,7 +100,7 @@ namespace Content.Server.GameObjects.Components.Atmos
                 return;
             }
 
-            status?.ShowAlert(AlertType.Fire, onClickAlert: OnClickAlert);
+            status?.ShowAlert(AlertType.Fire);
 
             if (FireStacks > 0)
             {
@@ -152,14 +152,6 @@ namespace Content.Server.GameObjects.Components.Atmos
             }
         }
 
-        private void OnClickAlert(ClickAlertEventArgs args)
-        {
-            if (args.Player.TryGetComponent(out FlammableComponent flammable))
-            {
-                flammable.Resist();
-            }
-        }
-
         public void CollideWith(IEntity collidedWith)
         {
             if (!collidedWith.TryGetComponent(out FlammableComponent otherFlammable))

Content.Server/GameObjects/Components/Atmos/GasTankComponent.cs

@@ -5,18 +5,22 @@ using Content.Server.Explosions;
 using Content.Server.GameObjects.Components.Body.Respiratory;
 using Content.Server.Interfaces;
 using Content.Server.Utility;
+using Content.Shared.Actions;
 using Content.Shared.Atmos;
 using Content.Shared.Audio;
 using Content.Shared.GameObjects.Components.Atmos.GasTank;
+using Content.Shared.GameObjects.Components.Mobs;
 using Content.Shared.GameObjects.EntitySystems;
 using Content.Shared.GameObjects.Verbs;
 using Content.Shared.Interfaces.GameObjects.Components;
+using JetBrains.Annotations;
 using Robust.Server.GameObjects.Components.UserInterface;
 using Robust.Server.GameObjects.EntitySystems;
 using Robust.Server.Interfaces.GameObjects;
 using Robust.Server.Interfaces.Player;
 using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
+using Robust.Shared.GameObjects.ComponentDependencies;
 using Robust.Shared.GameObjects.Systems;
 using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.Localization;
@@ -37,6 +41,8 @@ namespace Content.Server.GameObjects.Components.Atmos
 
         private int _integrity = 3;
 
+        [ComponentDependency] private readonly ItemActionsComponent? _itemActions = null;
+
         [ViewVariables] private BoundUserInterface? _userInterface;
 
         [ViewVariables] public GasMixture? Air { get; set; }
@@ -191,14 +197,18 @@ namespace Content.Server.GameObjects.Components.Atmos
 
         private void UpdateUserInterface(bool initialUpdate = false)
         {
+            var internals = GetInternalsComponent();
             _userInterface?.SetState(
                 new GasTankBoundUserInterfaceState
                 {
                     TankPressure = Air?.Pressure ?? 0,
                     OutputPressure = initialUpdate ? OutputPressure : (float?) null,
                     InternalsConnected = IsConnected,
-                    CanConnectInternals = IsFunctional && GetInternalsComponent() != null
+                    CanConnectInternals = IsFunctional && internals != null
                 });
+
+            if (internals == null) return;
+            _itemActions?.GrantOrUpdate(ItemActionType.ToggleInternals, IsFunctional, IsConnected);
         }
 
         private void UserInterfaceOnOnReceiveMessage(ServerBoundUserInterfaceMessage message)
@@ -214,8 +224,9 @@ namespace Content.Server.GameObjects.Components.Atmos
             }
         }
 
-        private void ToggleInternals()
+        internal void ToggleInternals()
         {
+            if (!ActionBlockerSystem.CanUse(GetInternalsComponent()?.Owner)) return;
             if (IsConnected)
             {
                 DisconnectFromInternals();
@@ -311,6 +322,11 @@ namespace Content.Server.GameObjects.Components.Atmos
                 _integrity++;
         }
 
+        public void Dropped(DroppedEventArgs eventArgs)
+        {
+            DisconnectFromInternals(eventArgs.User);
+        }
+
         /// <summary>
         /// Open interaction window
         /// </summary>
@@ -341,10 +357,21 @@ namespace Content.Server.GameObjects.Components.Atmos
                 component.OpenInterface(actor.playerSession);
             }
         }
+    }
 
-        public void Dropped(DroppedEventArgs eventArgs)
+    [UsedImplicitly]
+    public class ToggleInternalsAction : IToggleItemAction
     {
-            DisconnectFromInternals(eventArgs.User);
+        public void ExposeData(ObjectSerializer serializer) {}
+
+        public bool DoToggleAction(ToggleItemActionEventArgs args)
+        {
+            if (!args.Item.TryGetComponent<GasTankComponent>(out var gasTankComponent)) return false;
+            // no change
+            if (gasTankComponent.IsConnected == args.ToggledOn) return false;
+            gasTankComponent.ToggleInternals();
+            // did we successfully toggle to the desired status?
+            return gasTankComponent.IsConnected == args.ToggledOn;
         }
     }
 }

Content.Server/GameObjects/Components/Buckle/BuckleComponent.cs

@@ -108,8 +108,7 @@ namespace Content.Server.GameObjects.Components.Buckle
 
             if (Buckled)
             {
-                _serverAlertsComponent.ShowAlert(BuckledTo != null ? BuckledTo.BuckledAlertType : AlertType.Buckled,
-                    onClickAlert: OnClickAlert);
+                _serverAlertsComponent.ShowAlert(BuckledTo?.BuckledAlertType ?? AlertType.Buckled);
             }
             else
             {
@@ -117,14 +116,6 @@ namespace Content.Server.GameObjects.Components.Buckle
             }
         }
 
-        private void OnClickAlert(ClickAlertEventArgs args)
-        {
-            if (args.Player.TryGetComponent(out BuckleComponent? buckle))
-            {
-                buckle.TryUnbuckle(args.Player);
-            }
-        }
-
 
         /// <summary>
         ///     Reattaches this entity to the strap, modifying its position and rotation.

Content.Server/GameObjects/Components/GUI/HandsComponent.cs

@@ -30,6 +30,7 @@ namespace Content.Server.GameObjects.Components.GUI
     [RegisterComponent]
     [ComponentReference(typeof(IHandsComponent))]
     [ComponentReference(typeof(ISharedHandsComponent))]
+    [ComponentReference(typeof(SharedHandsComponent))]
     public class HandsComponent : SharedHandsComponent, IHandsComponent, IBodyPartAdded, IBodyPartRemoved
     {
         [Dependency] private readonly IEntitySystemManager _entitySystemManager = default!;
@@ -82,7 +83,7 @@ namespace Content.Server.GameObjects.Components.GUI
             }
         }
 
-        public bool IsHolding(IEntity entity)
+        public override bool IsHolding(IEntity entity)
         {
             foreach (var hand in _hands)
             {
@@ -165,6 +166,7 @@ namespace Content.Server.GameObjects.Components.GUI
             }
 
             Dirty();
+
             var success = hand.Container.Insert(item.Owner);
             if (success)
             {
@@ -172,6 +174,9 @@ namespace Content.Server.GameObjects.Components.GUI
                 OnItemChanged?.Invoke();
             }
 
+            _entitySystemManager.GetEntitySystem<InteractionSystem>().EquippedHandInteraction(Owner, item.Owner,
+                ToSharedHand(hand));
+
             _entitySystemManager.GetEntitySystem<InteractionSystem>().HandSelectedInteraction(Owner, item.Owner);
 
             return success;
@@ -266,6 +271,9 @@ namespace Content.Server.GameObjects.Components.GUI
                 return false;
             }
 
+            _entitySystemManager.GetEntitySystem<InteractionSystem>().UnequippedHandInteraction(Owner, item.Owner,
+                ToSharedHand(hand));
+
             if (doDropInteraction && !DroppedInteraction(item, false))
                 return false;
 
@@ -288,6 +296,61 @@ namespace Content.Server.GameObjects.Components.GUI
             return true;
         }
 
+
+        public bool Drop(string slot, BaseContainer targetContainer, bool doMobChecks = true, bool doDropInteraction = true)
+        {
+            if (slot == null)
+            {
+                throw new ArgumentNullException(nameof(slot));
+            }
+
+            if (targetContainer == null)
+            {
+                throw new ArgumentNullException(nameof(targetContainer));
+            }
+
+            var hand = GetHand(slot);
+            if (!CanDrop(slot, doMobChecks) || hand?.Entity == null)
+            {
+                return false;
+            }
+
+            if (!hand.Container.CanRemove(hand.Entity))
+            {
+                return false;
+            }
+
+            if (!targetContainer.CanInsert(hand.Entity))
+            {
+                return false;
+            }
+
+            var item = hand.Entity.GetComponent<ItemComponent>();
+
+            if (!hand.Container.Remove(hand.Entity))
+            {
+                throw new InvalidOperationException();
+            }
+
+            _entitySystemManager.GetEntitySystem<InteractionSystem>().UnequippedHandInteraction(Owner, item.Owner,
+                ToSharedHand(hand));
+
+            if (doDropInteraction && !DroppedInteraction(item, doMobChecks))
+                return false;
+
+            item.RemovedFromSlot();
+
+            if (!targetContainer.Insert(item.Owner))
+            {
+                throw new InvalidOperationException();
+            }
+
+            OnItemChanged?.Invoke();
+
+            Dirty();
+            return true;
+        }
+
         public bool Drop(IEntity entity, EntityCoordinates coords, bool doMobChecks = true, bool doDropInteraction = true)
         {
             if (entity == null)
@@ -323,57 +386,6 @@ namespace Content.Server.GameObjects.Components.GUI
             return Drop(slot, Owner.Transform.Coordinates, mobChecks, doDropInteraction);
         }
 
-        public bool Drop(string slot, BaseContainer targetContainer, bool doMobChecks = true, bool doDropInteraction = true)
-        {
-            if (slot == null)
-            {
-                throw new ArgumentNullException(nameof(slot));
-            }
-
-            if (targetContainer == null)
-            {
-                throw new ArgumentNullException(nameof(targetContainer));
-            }
-
-            var hand = GetHand(slot);
-            if (!CanDrop(slot, doMobChecks) || hand?.Entity == null)
-            {
-                return false;
-            }
-
-            if (!hand.Container.CanRemove(hand.Entity))
-            {
-                return false;
-            }
-
-            if (!targetContainer.CanInsert(hand.Entity))
-            {
-                return false;
-            }
-
-            var item = hand.Entity.GetComponent<ItemComponent>();
-
-            if (!hand.Container.Remove(hand.Entity))
-            {
-                throw new InvalidOperationException();
-            }
-
-            if (doDropInteraction && !DroppedInteraction(item, doMobChecks))
-                return false;
-
-            item.RemovedFromSlot();
-
-            if (!targetContainer.Insert(item.Owner))
-            {
-                throw new InvalidOperationException();
-            }
-
-            OnItemChanged?.Invoke();
-
-            Dirty();
-            return true;
-        }
-
         public bool Drop(IEntity entity, BaseContainer targetContainer, bool doMobChecks = true, bool doDropInteraction = true)
         {
             if (entity == null)
@@ -463,19 +475,28 @@ namespace Content.Server.GameObjects.Components.GUI
 
             for (var i = 0; i < _hands.Count; i++)
             {
-                var location = i == 0
-                    ? HandLocation.Right
-                    : i == _hands.Count - 1
-                        ? HandLocation.Left
-                        : HandLocation.Middle;
-
-                var hand = _hands[i].ToShared(i, location);
+                var hand = _hands[i].ToShared(i, IndexToHandLocation(i));
                 hands[i] = hand;
             }
 
             return new HandsComponentState(hands, ActiveHand);
         }
 
+        private HandLocation IndexToHandLocation(int index)
+        {
+            return index == 0
+                ? HandLocation.Right
+                : index == _hands.Count - 1
+                    ? HandLocation.Left
+                    : HandLocation.Middle;
+        }
+
+        private SharedHand ToSharedHand(Hand hand)
+        {
+            var index = _hands.IndexOf(hand);
+            return hand.ToShared(index, IndexToHandLocation(index));
+        }
+
         public void SwapHands()
         {
             if (ActiveHand == null)

Content.Server/GameObjects/Components/GUI/InventoryComponent.cs

@@ -25,6 +25,7 @@ using static Content.Shared.GameObjects.Components.Inventory.SharedInventoryComp
 namespace Content.Server.GameObjects.Components.GUI
 {
     [RegisterComponent]
+    [ComponentReference(typeof(SharedInventoryComponent))]
     public class InventoryComponent : SharedInventoryComponent, IExAct, IEffectBlocker, IPressureProtection
     {
         [Dependency] private readonly IEntitySystemManager _entitySystemManager = default!;
@@ -572,5 +573,20 @@ namespace Content.Server.GameObjects.Components.GUI
                 }
             }
         }
+
+        public override bool IsEquipped(IEntity item)
+        {
+            if (item == null) return false;
+            foreach (var containerSlot in _slotContainers.Values)
+            {
+                // we don't want a recursive check here
+                if (containerSlot.Contains(item))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
     }
 }

Content.Server/GameObjects/Components/Interactable/HandheldLightComponent.cs

@@ -1,18 +1,26 @@
 #nullable enable
 using System.Threading.Tasks;
+using Content.Server.GameObjects.Components.Atmos;
+using Content.Server.GameObjects.Components.GUI;
 using Content.Server.GameObjects.Components.Items.Clothing;
 using Content.Server.GameObjects.Components.Items.Storage;
+using Content.Server.GameObjects.Components.Mobs;
 using Content.Server.GameObjects.Components.Power;
+using Content.Shared.Actions;
 using Content.Server.GameObjects.Components.Weapon.Ranged.Barrels;
 using Content.Shared.GameObjects.Components;
+using Content.Shared.GameObjects.Components.Mobs;
 using Content.Shared.GameObjects.EntitySystems;
 using Content.Shared.GameObjects.Verbs;
 using Content.Shared.Interfaces;
 using Content.Shared.Interfaces.GameObjects.Components;
 using Content.Shared.Utility;
+using JetBrains.Annotations;
 using Robust.Server.GameObjects;
 using Robust.Server.GameObjects.EntitySystems;
+using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
+using Robust.Shared.GameObjects.ComponentDependencies;
 using Robust.Shared.GameObjects.Systems;
 using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.Localization;
@@ -45,6 +53,8 @@ namespace Content.Server.GameObjects.Components.Interactable
         [ViewVariables(VVAccess.ReadWrite)] public string? TurnOnFailSound;
         [ViewVariables(VVAccess.ReadWrite)] public string? TurnOffSound;
 
+        [ComponentDependency] private readonly ItemActionsComponent? _itemActions = null;
+
         /// <summary>
         ///     Client-side ItemStatus level
         /// </summary>
@@ -98,8 +108,9 @@ namespace Content.Server.GameObjects.Components.Interactable
         ///     Illuminates the light if it is not active, extinguishes it if it is active.
         /// </summary>
         /// <returns>True if the light's status was toggled, false otherwise.</returns>
-        private bool ToggleStatus(IEntity user)
+        public bool ToggleStatus(IEntity user)
         {
+            if (!ActionBlockerSystem.CanUse(user)) return false;
             return Activated ? TurnOff() : TurnOn(user);
         }
 
@@ -112,6 +123,7 @@ namespace Content.Server.GameObjects.Components.Interactable
 
             SetState(false);
             Activated = false;
+            UpdateLightAction();
 
             if (makeNoise)
             {
@@ -132,6 +144,7 @@ namespace Content.Server.GameObjects.Components.Interactable
             {
                 if (TurnOnFailSound != null) EntitySystem.Get<AudioSystem>().PlayFromEntity(TurnOnFailSound, Owner);
                 Owner.PopupMessage(user, Loc.GetString("Cell missing..."));
+                UpdateLightAction();
                 return false;
             }
 
@@ -142,10 +155,12 @@ namespace Content.Server.GameObjects.Components.Interactable
             {
                 if (TurnOnFailSound != null) EntitySystem.Get<AudioSystem>().PlayFromEntity(TurnOnFailSound, Owner);
                 Owner.PopupMessage(user, Loc.GetString("Dead cell..."));
+                UpdateLightAction();
                 return false;
             }
 
             Activated = true;
+            UpdateLightAction();
             SetState(true);
 
             if (TurnOnSound != null) EntitySystem.Get<AudioSystem>().PlayFromEntity(TurnOnSound, Owner);
@@ -175,6 +190,11 @@ namespace Content.Server.GameObjects.Components.Interactable
             }
         }
 
+        private void UpdateLightAction()
+        {
+            _itemActions?.Toggle(ItemActionType.ToggleLight, Activated);
+        }
+
         public void OnUpdate(float frameTime)
         {
             if (Cell == null)
@@ -249,4 +269,17 @@ namespace Content.Server.GameObjects.Components.Interactable
             }
         }
     }
+
+    [UsedImplicitly]
+    public class ToggleLightAction : IToggleItemAction
+    {
+        public void ExposeData(ObjectSerializer serializer) {}
+
+        public bool DoToggleAction(ToggleItemActionEventArgs args)
+        {
+            if (!args.Item.TryGetComponent<HandheldLightComponent>(out var lightComponent)) return false;
+            if (lightComponent.Activated == args.ToggledOn) return false;
+            return lightComponent.ToggleStatus(args.Performer);
+        }
+    }
 }

Content.Server/GameObjects/Components/Items/DebugEquipComponent.cs

@@ -0,0 +1,35 @@
+using Content.Shared.Interfaces;
+using Content.Shared.Interfaces.GameObjects.Components;
+using Robust.Shared.GameObjects;
+
+namespace Content.Server.GameObjects.Components.Items
+{
+    /// <summary>
+    /// Pops up a message when equipped / unequipped (including hands).
+    /// For debugging purposes.
+    /// </summary>
+    [RegisterComponent]
+    public class DebugEquipComponent : Component, IEquipped, IEquippedHand, IUnequipped, IUnequippedHand
+    {
+        public override string Name => "DebugEquip";
+        public void Equipped(EquippedEventArgs eventArgs)
+        {
+            eventArgs.User.PopupMessage("equipped " + Owner.Name);
+        }
+
+        public void EquippedHand(EquippedHandEventArgs eventArgs)
+        {
+            eventArgs.User.PopupMessage("equipped hand " + Owner.Name);
+        }
+
+        public void Unequipped(UnequippedEventArgs eventArgs)
+        {
+            eventArgs.User.PopupMessage("unequipped " + Owner.Name);
+        }
+
+        public void UnequippedHand(UnequippedHandEventArgs eventArgs)
+        {
+            eventArgs.User.PopupMessage("unequipped hand" + Owner.Name);
+        }
+    }
+}

Content.Server/GameObjects/Components/Mobs/ServerActionsComponent.cs

@@ -0,0 +1,199 @@
+#nullable enable
+using System;
+using Content.Shared.Actions;
+using Content.Shared.GameObjects.Components.Mobs;
+using Content.Shared.GameObjects.EntitySystems;
+using Robust.Server.Interfaces.GameObjects;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Network;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+using Robust.Shared.Players;
+
+namespace Content.Server.GameObjects.Components.Mobs
+{
+    [RegisterComponent]
+    [ComponentReference(typeof(SharedActionsComponent))]
+    public sealed class ServerActionsComponent : SharedActionsComponent
+    {
+        [Dependency] private readonly IServerEntityManager _entityManager = default!;
+
+        public override void HandleNetworkMessage(ComponentMessage message, INetChannel netChannel, ICommonSession? session = null)
+        {
+            base.HandleNetworkMessage(message, netChannel, session);
+
+            if (message is not BasePerformActionMessage performActionMessage) return;
+            if (session == null)
+            {
+                throw new ArgumentNullException(nameof(session));
+            }
+
+            var player = session.AttachedEntity;
+            if (player != Owner) return;
+            var attempt = ActionAttempt(performActionMessage, session);
+            if (attempt == null) return;
+
+            if (!attempt.TryGetActionState(this, out var actionState) || !actionState.Enabled)
+            {
+                Logger.DebugS("action", "user {0} attempted to use" +
+                                        " action {1} which is not granted to them", player.Name,
+                    attempt);
+                return;
+            }
+
+            if (actionState.IsOnCooldown(GameTiming))
+            {
+                Logger.DebugS("action", "user {0} attempted to use" +
+                                        " action {1} which is on cooldown", player.Name,
+                    attempt);
+                return;
+            }
+
+            switch (performActionMessage.BehaviorType)
+            {
+                case BehaviorType.Instant:
+                    attempt.DoInstantAction(player);
+                    break;
+                case BehaviorType.Toggle:
+                    if (performActionMessage is not IToggleActionMessage toggleMsg) return;
+                    if (toggleMsg.ToggleOn == actionState.ToggledOn)
+                    {
+                        Logger.DebugS("action", "user {0} attempted to" +
+                                                " toggle action {1} to {2}, but it is already toggled {2}", player.Name,
+                            attempt.Action.Name, toggleMsg.ToggleOn);
+                        return;
+                    }
+
+                    if (attempt.DoToggleAction(player, toggleMsg.ToggleOn))
+                    {
+                        attempt.ToggleAction(this, toggleMsg.ToggleOn);
+                    }
+                    else
+                    {
+                        // if client predicted the toggle will work, need to reset
+                        // that prediction
+                        Dirty();
+                    }
+                    break;
+                case BehaviorType.TargetPoint:
+                    if (performActionMessage is not ITargetPointActionMessage targetPointMsg) return;
+                    if (!CheckRangeAndSetFacing(targetPointMsg.Target, player)) return;
+                    attempt.DoTargetPointAction(player, targetPointMsg.Target);
+                    break;
+                case BehaviorType.TargetEntity:
+                    if (performActionMessage is not ITargetEntityActionMessage targetEntityMsg) return;
+                    if (!EntityManager.TryGetEntity(targetEntityMsg.Target, out var entity))
+                    {
+                        Logger.DebugS("action", "user {0} attempted to" +
+                                                " perform target entity action {1} but could not find entity with " +
+                                                "provided uid {2}", player.Name, attempt.Action.Name,
+                            targetEntityMsg.Target);
+                        return;
+                    }
+                    if (!CheckRangeAndSetFacing(entity.Transform.Coordinates, player)) return;
+
+                    attempt.DoTargetEntityAction(player, entity);
+                    break;
+                case BehaviorType.None:
+                    break;
+                default:
+                    throw new ArgumentOutOfRangeException();
+            }
+        }
+
+        private IActionAttempt? ActionAttempt(BasePerformActionMessage message, ICommonSession session)
+        {
+            IActionAttempt? attempt;
+            switch (message)
+            {
+                case PerformActionMessage performActionMessage:
+                    if (!ActionManager.TryGet(performActionMessage.ActionType, out var action))
+                    {
+                        Logger.DebugS("action", "user {0} attempted to perform" +
+                                                " unrecognized action {1}", session.AttachedEntity,
+                            performActionMessage.ActionType);
+                        return null;
+                    }
+                    attempt = new ActionAttempt(action);
+                    break;
+                case PerformItemActionMessage performItemActionMessage:
+                    if (!ActionManager.TryGet(performItemActionMessage.ActionType, out var itemAction))
+                    {
+                        Logger.DebugS("action", "user {0} attempted to perform" +
+                                                " unrecognized item action {1}",
+                            session.AttachedEntity, performItemActionMessage.ActionType);
+                        return null;
+                    }
+
+                    if (!EntityManager.TryGetEntity(performItemActionMessage.Item, out var item))
+                    {
+                        Logger.DebugS("action", "user {0} attempted to perform" +
+                                                " item action {1} for unknown item {2}",
+                            session.AttachedEntity, performItemActionMessage.ActionType, performItemActionMessage.Item);
+                        return null;
+                    }
+
+                    if (!item.TryGetComponent<ItemActionsComponent>(out var actionsComponent))
+                    {
+                        Logger.DebugS("action", "user {0} attempted to perform" +
+                                                " item action {1} for item {2} which has no ItemActionsComponent",
+                            session.AttachedEntity, performItemActionMessage.ActionType, item);
+                        return null;
+                    }
+
+                    if (actionsComponent.Holder != session.AttachedEntity)
+                    {
+                        Logger.DebugS("action", "user {0} attempted to perform" +
+                                                " item action {1} for item {2} which they are not holding",
+                            session.AttachedEntity, performItemActionMessage.ActionType, item);
+                        return null;
+                    }
+
+                    attempt = new ItemActionAttempt(itemAction, item, actionsComponent);
+                    break;
+                default:
+                    return null;
+            }
+
+            if (message.BehaviorType != attempt.Action.BehaviorType)
+            {
+                Logger.DebugS("action", "user {0} attempted to" +
+                                        " perform action {1} as a {2} behavior, but this action is actually a" +
+                                        " {3} behavior", session.AttachedEntity, attempt, message.BehaviorType,
+                    attempt.Action.BehaviorType);
+                return null;
+            }
+
+            return attempt;
+        }
+
+        private bool CheckRangeAndSetFacing(EntityCoordinates target, IEntity player)
+        {
+            // ensure it's within their clickable range
+            var targetWorldPos = target.ToMapPos(EntityManager);
+            var rangeBox = new Box2(player.Transform.WorldPosition, player.Transform.WorldPosition)
+                .Enlarged(_entityManager.MaxUpdateRange);
+            if (!rangeBox.Contains(targetWorldPos))
+            {
+                Logger.DebugS("action", "user {0} attempted to" +
+                                        " perform target action further than allowed range",
+                    player.Name);
+                return false;
+            }
+
+            if (!ActionBlockerSystem.CanChangeDirection(player)) return true;
+
+            // don't set facing unless they clicked far enough away
+            var diff = targetWorldPos - player.Transform.WorldPosition;
+            if (diff.LengthSquared > 0.01f)
+            {
+                player.Transform.LocalRotation = new Angle(diff);
+            }
+
+            return true;
+        }
+    }
+}

Content.Server/GameObjects/Components/Mobs/ServerAlertsComponent.cs

@@ -1,5 +1,6 @@
 using System;
 using Content.Server.GameObjects.EntitySystems;
+using Content.Shared.Alert;
 using Content.Shared.GameObjects.Components.Mobs;
 using Robust.Shared.GameObjects;
 using Robust.Shared.GameObjects.Systems;
@@ -42,11 +43,6 @@ namespace Content.Server.GameObjects.Components.Mobs
             base.OnRemove();
         }
 
-        public override ComponentState GetComponentState()
-        {
-            return new AlertsComponentState(CreateAlertStatesArray());
-        }
-
         public override void HandleNetworkMessage(ComponentMessage message, INetChannel netChannel, ICommonSession session = null)
         {
             base.HandleNetworkMessage(message, netChannel, session);
@@ -67,14 +63,21 @@ namespace Content.Server.GameObjects.Components.Mobs
                         break;
                     }
 
-                    // TODO: Implement clicking other status effects in the HUD
-                    if (AlertManager.TryDecode(msg.EncodedAlert, out var alert))
+                    if (!IsShowingAlert(msg.AlertType))
                     {
-                        PerformAlertClickCallback(alert, player);
+                        Logger.DebugS("alert", "user {0} attempted to" +
+                                              " click alert {1} which is not currently showing for them",
+                            player.Name, msg.AlertType);
+                        break;
+                    }
+
+                    if (AlertManager.TryGet(msg.AlertType, out var alert))
+                    {
+                        alert.OnClick.AlertClicked(new ClickAlertEventArgs(player, alert));
                     }
                     else
                     {
-                        Logger.WarningS("alert", "unrecognized encoded alert {0}", msg.EncodedAlert);
+                        Logger.WarningS("alert", "unrecognized encoded alert {0}", msg.AlertType);
                     }
 
                     break;

Content.Server/GameObjects/Components/Movement/ShuttleControllerComponent.cs

@@ -145,15 +145,7 @@ namespace Content.Server.GameObjects.Components.Movement
             mind.Mind.Visit(Owner);
             _controller = entity;
 
-            status.ShowAlert(_pilotingAlertType, onClickAlert: OnClickAlert);
-        }
-
-        private void OnClickAlert(ClickAlertEventArgs args)
-        {
-            if (args.Player.TryGetComponent(out ShuttleControllerComponent? controller))
-            {
-                controller.RemoveController();
-            }
+            status.ShowAlert(_pilotingAlertType);
         }
 
         /// <summary>

Content.Server/GameObjects/EntitySystems/Click/InteractionSystem.cs

@@ -1,12 +1,14 @@
 using System;
 using System.Linq;
 using System.Threading.Tasks;
+using Content.Server.GameObjects.Components.GUI;
 using Content.Server.GameObjects.Components.Items.Storage;
 using Content.Server.GameObjects.Components.Mobs;
 using Content.Server.GameObjects.Components.Pulling;
 using Content.Server.GameObjects.Components.Timing;
 using Content.Server.Interfaces.GameObjects.Components.Items;
 using Content.Shared.GameObjects.Components.Inventory;
+using Content.Shared.GameObjects.Components.Items;
 using Content.Shared.GameObjects.EntitySystemMessages;
 using Content.Shared.GameObjects.EntitySystems;
 using Content.Shared.Input;
@@ -113,11 +115,9 @@ namespace Content.Server.GameObjects.EntitySystems.Click
         }
 
         /// <summary>
-        /// Activates the Activate behavior of an object
+        /// Activates the IActivate behavior of an object
         /// Verifies that the user is capable of doing the use interaction first
         /// </summary>
-        /// <param name="user"></param>
-        /// <param name="used"></param>
         public void TryInteractionActivate(IEntity user, IEntity used)
         {
             if (user != null && used != null && ActionBlockerSystem.CanUse(user))
@@ -504,7 +504,7 @@ namespace Content.Server.GameObjects.EntitySystems.Click
         }
 
         /// <summary>
-        /// Activates the Use behavior of an object
+        /// Activates the IUse behaviors of an entity
         /// Verifies that the user is capable of doing the use interaction first
         /// </summary>
         /// <param name="user"></param>
@@ -518,8 +518,8 @@ namespace Content.Server.GameObjects.EntitySystems.Click
         }
 
         /// <summary>
-        /// Activates/Uses an object in control/possession of a user
-        /// If the item has the IUse interface on one of its components we use the object in our hand
+        /// Activates the IUse behaviors of an entity without first checking
+        /// if the user is capable of doing the use interaction.
         /// </summary>
         public void UseInteraction(IEntity user, IEntity used)
         {
@@ -679,6 +679,48 @@ namespace Content.Server.GameObjects.EntitySystems.Click
             }
         }
 
+        /// <summary>
+        ///     Calls EquippedHand on all components that implement the IEquippedHand interface
+        ///     on an item.
+        /// </summary>
+        public void EquippedHandInteraction(IEntity user, IEntity item, SharedHand hand)
+        {
+            var equippedHandMessage = new EquippedHandMessage(user, item, hand);
+            RaiseLocalEvent(equippedHandMessage);
+            if (equippedHandMessage.Handled)
+            {
+                return;
+            }
+
+            var comps = item.GetAllComponents<IEquippedHand>().ToList();
+
+            foreach (var comp in comps)
+            {
+                comp.EquippedHand(new EquippedHandEventArgs(user, hand));
+            }
+        }
+
+        /// <summary>
+        ///     Calls UnequippedHand on all components that implement the IUnequippedHand interface
+        ///     on an item.
+        /// </summary>
+        public void UnequippedHandInteraction(IEntity user, IEntity item, SharedHand hand)
+        {
+            var unequippedHandMessage = new UnequippedHandMessage(user, item, hand);
+            RaiseLocalEvent(unequippedHandMessage);
+            if (unequippedHandMessage.Handled)
+            {
+                return;
+            }
+
+            var comps = item.GetAllComponents<IUnequippedHand>().ToList();
+
+            foreach (var comp in comps)
+            {
+                comp.UnequippedHand(new UnequippedHandEventArgs(user, hand));
+            }
+        }
+
         /// <summary>
         /// Activates the Dropped behavior of an object
         /// Verifies that the user is capable of doing the drop interaction first
@@ -757,7 +799,6 @@ namespace Content.Server.GameObjects.EntitySystems.Click
             }
         }
 
-
         /// <summary>
         /// Will have two behaviors, either "uses" the weapon at range on the entity if it is capable of accepting that action
         /// Or it will use the weapon itself on the position clicked, regardless of what was there

Content.Server/ServerContentIoC.cs

@@ -20,6 +20,7 @@ using Content.Server.PDA;
 using Content.Server.Preferences;
 using Content.Server.Sandbox;
 using Content.Server.Utility;
+using Content.Shared.Actions;
 using Content.Shared.Interfaces;
 using Content.Shared.Kitchen;
 using Content.Shared.Alert;
@@ -43,6 +44,7 @@ namespace Content.Server
             IoCManager.Register<IServerDbManager, ServerDbManager>();
             IoCManager.Register<RecipeManager, RecipeManager>();
             IoCManager.Register<AlertManager, AlertManager>();
+            IoCManager.Register<ActionManager, ActionManager>();
             IoCManager.Register<IPDAUplinkManager,PDAUplinkManager>();
             IoCManager.Register<INodeGroupFactory, NodeGroupFactory>();
             IoCManager.Register<INodeGroupManager, NodeGroupManager>();

Content.Shared/Actions/ActionManager.cs

@@ -0,0 +1,70 @@
+using System.Collections.Generic;
+using System.Linq;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Robust.Shared.Prototypes;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Provides access to all configured actions by action type.
+    /// </summary>
+    public class ActionManager
+    {
+        [Dependency]
+        private readonly IPrototypeManager _prototypeManager = default!;
+
+        private Dictionary<ActionType, ActionPrototype> _typeToAction;
+        private Dictionary<ItemActionType, ItemActionPrototype> _typeToItemAction;
+
+        public void Initialize()
+        {
+            _typeToAction = new Dictionary<ActionType, ActionPrototype>();
+            foreach (var action in _prototypeManager.EnumeratePrototypes<ActionPrototype>())
+            {
+                if (!_typeToAction.TryAdd(action.ActionType, action))
+                {
+                    Logger.ErrorS("action",
+                        "Found action with duplicate actionType {0} - all actions must have" +
+                        " a unique actionType, this one will be skipped", action.ActionType);
+                }
+            }
+
+            _typeToItemAction = new Dictionary<ItemActionType, ItemActionPrototype>();
+            foreach (var action in _prototypeManager.EnumeratePrototypes<ItemActionPrototype>())
+            {
+                if (!_typeToItemAction.TryAdd(action.ActionType, action))
+                {
+                    Logger.ErrorS("action",
+                        "Found itemAction with duplicate actionType {0} - all actions must have" +
+                        " a unique actionType, this one will be skipped", action.ActionType);
+                }
+            }
+        }
+
+        /// <returns>all action prototypes of all types</returns>
+        public IEnumerable<BaseActionPrototype> EnumerateActions()
+        {
+            return _typeToAction.Values.Concat<BaseActionPrototype>(_typeToItemAction.Values);
+        }
+
+
+        /// <summary>
+        /// Tries to get the action of the indicated type
+        /// </summary>
+        /// <returns>true if found</returns>
+        public bool TryGet(ActionType actionType, out ActionPrototype action)
+        {
+            return _typeToAction.TryGetValue(actionType, out action);
+        }
+
+        /// <summary>
+        /// Tries to get the item action of the indicated type
+        /// </summary>
+        /// <returns>true if found</returns>
+        public bool TryGet(ItemActionType actionType, out ItemActionPrototype action)
+        {
+            return _typeToItemAction.TryGetValue(actionType, out action);
+        }
+    }
+}

Content.Shared/Actions/ActionPrototype.cs

@@ -0,0 +1,100 @@
+using Content.Shared.Interfaces;
+using Robust.Shared.IoC;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization;
+using YamlDotNet.RepresentationModel;
+using Robust.Shared.Log;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// An action which is granted directly to an entity (such as an innate ability
+    /// or skill).
+    /// </summary>
+    [Prototype("action")]
+    public class ActionPrototype : BaseActionPrototype
+    {
+        /// <summary>
+        /// Type of action, no 2 action prototypes should have the same one.
+        /// </summary>
+        public ActionType ActionType { get; private set; }
+
+        /// <summary>
+        /// The IInstantAction that should be invoked when performing this
+        /// action. Null if this is not an Instant ActionBehaviorType.
+        /// Will be null on client side if the behavior is not in Content.Client.
+        /// </summary>
+        public IInstantAction InstantAction { get; private set; }
+
+        /// <summary>
+        /// The IToggleAction that should be invoked when performing this
+        /// action. Null if this is not a Toggle ActionBehaviorType.
+        /// Will be null on client side if the behavior is not in Content.Client.
+        /// </summary>
+        public IToggleAction ToggleAction { get; private set; }
+
+        /// <summary>
+        /// The ITargetEntityAction that should be invoked when performing this
+        /// action. Null if this is not a TargetEntity ActionBehaviorType.
+        /// Will be null on client side if the behavior is not in Content.Client.
+        /// </summary>
+        public ITargetEntityAction TargetEntityAction { get; private set; }
+
+        /// <summary>
+        /// The ITargetPointAction that should be invoked when performing this
+        /// action. Null if this is not a TargetPoint ActionBehaviorType.
+        /// Will be null on client side if the behavior is not in Content.Client.
+        /// </summary>
+        public ITargetPointAction TargetPointAction { get; private set; }
+
+        public override void LoadFrom(YamlMappingNode mapping)
+        {
+            base.LoadFrom(mapping);
+            var serializer = YamlObjectSerializer.NewReader(mapping);
+
+            serializer.DataField(this, x => x.ActionType, "actionType", ActionType.Error);
+            if (ActionType == ActionType.Error)
+            {
+                Logger.ErrorS("action", "missing or invalid actionType for action with name {0}", Name);
+            }
+
+            // TODO: Split this class into server/client after RobustToolbox#1405
+            if (IoCManager.Resolve<IModuleManager>().IsClientModule) return;
+
+            IActionBehavior behavior = null;
+            serializer.DataField(ref behavior, "behavior", null);
+            switch (behavior)
+            {
+                case null:
+                    BehaviorType = BehaviorType.None;
+                    Logger.ErrorS("action", "missing or invalid behavior for action with name {0}", Name);
+                    break;
+                case IInstantAction instantAction:
+                    ValidateBehaviorType(BehaviorType.Instant, typeof(IInstantAction));
+                    BehaviorType = BehaviorType.Instant;
+                    InstantAction = instantAction;
+                    break;
+                case IToggleAction toggleAction:
+                    ValidateBehaviorType(BehaviorType.Toggle, typeof(IToggleAction));
+                    BehaviorType = BehaviorType.Toggle;
+                    ToggleAction = toggleAction;
+                    break;
+                case ITargetEntityAction targetEntity:
+                    ValidateBehaviorType(BehaviorType.TargetEntity, typeof(ITargetEntityAction));
+                    BehaviorType = BehaviorType.TargetEntity;
+                    TargetEntityAction = targetEntity;
+                    break;
+                case ITargetPointAction targetPointAction:
+                    ValidateBehaviorType(BehaviorType.TargetPoint, typeof(ITargetPointAction));
+                    BehaviorType = BehaviorType.TargetPoint;
+                    TargetPointAction = targetPointAction;
+                    break;
+                default:
+                    BehaviorType = BehaviorType.None;
+                    Logger.ErrorS("action", "unrecognized behavior type for action with name {0}", Name);
+                    break;
+            }
+
+        }
+    }
+}

Content.Shared/Actions/ActionType.cs

@@ -0,0 +1,33 @@
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Every possible action. Corresponds to actionType in action prototypes.
+    /// </summary>
+    public enum ActionType : byte
+    {
+        Error,
+        HumanScream,
+        DebugInstant,
+        DebugToggle,
+        DebugTargetPoint,
+        DebugTargetPointRepeat,
+        DebugTargetEntity,
+        DebugTargetEntityRepeat
+    }
+
+    /// <summary>
+    /// Every possible item action. Corresponds to actionType in itemAction prototypes.
+    /// </summary>
+    public enum ItemActionType : byte
+    {
+        Error,
+        ToggleInternals,
+        ToggleLight,
+        DebugInstant,
+        DebugToggle,
+        DebugTargetPoint,
+        DebugTargetPointRepeat,
+        DebugTargetEntity,
+        DebugTargetEntityRepeat
+    }
+}

Content.Shared/Actions/BaseActionPrototype.cs

@@ -0,0 +1,166 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Content.Shared.Interfaces;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization;
+using Robust.Shared.Utility;
+using Robust.Shared.ViewVariables;
+using YamlDotNet.RepresentationModel;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Base class for action prototypes.
+    /// </summary>
+    public abstract class BaseActionPrototype : IPrototype
+    {
+        /// <summary>
+        /// Icon representing this action in the UI.
+        /// </summary>
+        [ViewVariables]
+        public SpriteSpecifier Icon { get; private set; }
+
+        /// <summary>
+        /// For toggle actions only, icon to show when toggled on. If omitted,
+        /// the action will simply be highlighted when turned on.
+        /// </summary>
+        [ViewVariables]
+        public SpriteSpecifier IconOn { get; private set; }
+
+
+
+        /// <summary>
+        /// Name to show in UI. Accepts formatting.
+        /// </summary>
+        public FormattedMessage Name { get; private set; }
+
+        /// <summary>
+        /// Description to show in UI. Accepts formatting.
+        /// </summary>
+        public FormattedMessage Description { get; private set; }
+
+        /// <summary>
+        /// Requirements message to show in UI. Accepts formatting, but generally should be avoided
+        /// so the requirements message isn't too prominent in the tooltip.
+        /// </summary>
+        public string Requires { get; private set; }
+
+        /// <summary>
+        /// The type of behavior this action has. This is valid clientside and serverside.
+        /// </summary>
+        public BehaviorType BehaviorType { get; protected set; }
+
+        /// <summary>
+        /// For targetpoint or targetentity actions, if this is true the action will remain
+        /// selected after it is used, so it can be continuously re-used. If this is false,
+        /// the action will be deselected after one use.
+        /// </summary>
+        public bool Repeat { get; private set; }
+
+        /// <summary>
+        /// Filters that can be used to filter this item in action menu.
+        /// </summary>
+        public IEnumerable<string> Filters { get; private set; }
+
+        /// <summary>
+        /// Keywords that can be used to search this item in action menu.
+        /// </summary>
+        public IEnumerable<string> Keywords { get; private set; }
+
+        public virtual void LoadFrom(YamlMappingNode mapping)
+        {
+            var serializer = YamlObjectSerializer.NewReader(mapping);
+
+            serializer.DataReadFunction("name", string.Empty,
+                s => Name = FormattedMessage.FromMarkup(s));
+            serializer.DataReadFunction("description", string.Empty,
+                s => Description = FormattedMessage.FromMarkup(s));
+
+            serializer.DataField(this, x => x.Requires,"requires", null);
+            serializer.DataField(this, x => x.Icon,"icon", SpriteSpecifier.Invalid);
+            serializer.DataField(this, x => x.IconOn,"iconOn", SpriteSpecifier.Invalid);
+
+            // client needs to know what type of behavior it is even if the actual implementation is only
+            // on server side. If we wanted to avoid this we'd need to always add a shared or clientside interface
+            // for each action even if there was only server-side logic, which would be cumbersome
+            serializer.DataField(this, x => x.BehaviorType, "behaviorType", BehaviorType.None);
+            if (BehaviorType == BehaviorType.None)
+            {
+                Logger.ErrorS("action", "Missing behaviorType for action with name {0}", Name);
+            }
+
+            if (BehaviorType != BehaviorType.Toggle && IconOn != SpriteSpecifier.Invalid)
+            {
+                Logger.ErrorS("action", "for action {0}, iconOn was specified but behavior" +
+                                        " type was {1}. iconOn is only supported for Toggle behavior type.", Name);
+            }
+
+            serializer.DataField(this, x => x.Repeat, "repeat", false);
+            if (Repeat && BehaviorType != BehaviorType.TargetEntity && BehaviorType != BehaviorType.TargetPoint)
+            {
+                Logger.ErrorS("action", " action named {0} used repeat: true, but this is only supported for" +
+                                        " TargetEntity and TargetPoint behaviorType and its behaviorType is {1}",
+                    Name, BehaviorType);
+            }
+
+            serializer.DataReadFunction("filters", new List<string>(),
+                rawTags =>
+                {
+                    Filters = rawTags.Select(rawTag => rawTag.Trim()).ToList();
+                });
+
+            serializer.DataReadFunction("keywords", new List<string>(),
+                rawTags =>
+                {
+                    Keywords = rawTags.Select(rawTag => rawTag.Trim()).ToList();
+                });
+        }
+
+        protected void ValidateBehaviorType(BehaviorType expected, Type actualInterface)
+        {
+            if (BehaviorType != expected)
+            {
+                Logger.ErrorS("action", "for action named {0}, behavior implements " +
+                                        "{1}, so behaviorType should be {2} but was {3}", Name, actualInterface.Name, expected, BehaviorType);
+            }
+        }
+    }
+
+    /// <summary>
+    /// The behavior / logic of the action. Each of these corresponds to a particular IActionBehavior
+    /// (for actions) or IItemActionBehavior (for item actions)
+    /// interface. Corresponds to action.behaviorType in YAML
+    /// </summary>
+    public enum BehaviorType
+    {
+        /// <summary>
+        /// Action doesn't do anything.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// IInstantAction/IInstantItemAction. Action which does something immediately when used and has
+        /// no target.
+        /// </summary>
+        Instant,
+
+        /// <summary>
+        /// IToggleAction/IToggleItemAction Action which can be toggled on and off
+        /// </summary>
+        Toggle,
+
+        /// <summary>
+        /// ITargetEntityAction/ITargetEntityItemAction. Action which is used on a targeted entity.
+        /// </summary>
+        TargetEntity,
+
+        /// <summary>
+        /// ITargetPointAction/ITargetPointItemAction. Action which requires the user to select a target point, which
+        /// does not necessarily have an entity on it.
+        /// </summary>
+        TargetPoint
+    }
+}

Content.Shared/Actions/IActionBehavior.cs

@@ -0,0 +1,44 @@
+using System;
+using Content.Shared.GameObjects.Components.Mobs;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Serialization;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Currently just a marker interface delineating the different possible
+    /// types of action behaviors.
+    /// </summary>
+    public interface IActionBehavior : IExposeData { }
+
+    /// <summary>
+    /// Base class for all action event args
+    /// </summary>
+    public abstract class ActionEventArgs : EventArgs
+    {
+        /// <summary>
+        /// Entity performing the action.
+        /// </summary>
+        public readonly IEntity Performer;
+        /// <summary>
+        /// Action being performed
+        /// </summary>
+        public readonly ActionType ActionType;
+        /// <summary>
+        /// Actions component of the performer.
+        /// </summary>
+        public readonly SharedActionsComponent PerformerActions;
+
+        public ActionEventArgs(IEntity performer, ActionType actionType)
+        {
+            Performer = performer;
+            ActionType = actionType;
+            if (!Performer.TryGetComponent(out PerformerActions))
+            {
+                throw new InvalidOperationException($"performer {performer.Name} tried to perform action {actionType} " +
+                                                    $" but the performer had no actions component," +
+                                                    " which should never occur");
+            }
+        }
+    }
+}

Content.Shared/Actions/IInstantAction.cs

@@ -0,0 +1,27 @@
+using System;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Serialization;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Action which does something immediately when used and has
+    /// no target.
+    /// </summary>
+    public interface IInstantAction : IActionBehavior
+    {
+
+        /// <summary>
+        /// Invoked when the instant action should be performed.
+        /// Implementation should perform the server side logic of the action.
+        /// </summary>
+        void DoInstantAction(InstantActionEventArgs args);
+    }
+
+    public class InstantActionEventArgs : ActionEventArgs
+    {
+        public InstantActionEventArgs(IEntity performer, ActionType actionType) : base(performer, actionType)
+        {
+        }
+    }
+}

Content.Shared/Actions/IInstantItemAction.cs

@@ -0,0 +1,28 @@
+using System;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Serialization;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Item action which does something immediately when used and has
+    /// no target.
+    /// </summary>
+    public interface IInstantItemAction : IItemActionBehavior
+    {
+
+        /// <summary>
+        /// Invoked when the instant action should be performed.
+        /// Implementation should perform the server side logic of the action.
+        /// </summary>
+        void DoInstantAction(InstantItemActionEventArgs args);
+    }
+
+    public class InstantItemActionEventArgs : ItemActionEventArgs
+    {
+        public InstantItemActionEventArgs(IEntity performer, IEntity item, ItemActionType actionType) :
+            base(performer, item, actionType)
+        {
+        }
+    }
+}

Content.Shared/Actions/IItemActionBehavior.cs

@@ -0,0 +1,52 @@
+using System;
+using Content.Shared.GameObjects.Components.Mobs;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Serialization;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Currently just a marker interface delineating the different possible
+    /// types of item action behaviors.
+    /// </summary>
+    public interface IItemActionBehavior : IExposeData
+    {
+
+    }
+
+    /// <summary>
+    /// Base class for all item action event args
+    /// </summary>
+    public abstract class ItemActionEventArgs : EventArgs
+    {
+        /// <summary>
+        /// Entity performing the action.
+        /// </summary>
+        public readonly IEntity Performer;
+        /// <summary>
+        /// Item being used to perform the action
+        /// </summary>
+        public readonly IEntity Item;
+        /// <summary>
+        /// Action being performed
+        /// </summary>
+        public readonly ItemActionType ActionType;
+        /// <summary>
+        /// Item actions component of the item.
+        /// </summary>
+        public readonly ItemActionsComponent ItemActions;
+
+        public ItemActionEventArgs(IEntity performer, IEntity item, ItemActionType actionType)
+        {
+            Performer = performer;
+            ActionType = actionType;
+            Item = item;
+            if (!Item.TryGetComponent(out ItemActions))
+            {
+                throw new InvalidOperationException($"performer {performer.Name} tried to perform item action {actionType} " +
+                                                    $" for item {Item.Name} but the item had no ItemActionsComponent," +
+                                                    " which should never occur");
+            }
+        }
+    }
+}

Content.Shared/Actions/ITargetEntityAction.cs

@@ -0,0 +1,33 @@
+using System;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Serialization;
+using Robust.Shared.Map;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Action which is used on a targeted entity.
+    /// </summary>
+    public interface ITargetEntityAction : IActionBehavior
+    {
+        /// <summary>
+        /// Invoked when the target entity action should be performed.
+        /// Implementation should perform the server side logic of the action.
+        /// </summary>
+        void DoTargetEntityAction(TargetEntityActionEventArgs args);
+    }
+
+    public class TargetEntityActionEventArgs : ActionEventArgs
+    {
+        /// <summary>
+        /// Entity being targeted
+        /// </summary>
+        public readonly IEntity Target;
+
+        public TargetEntityActionEventArgs(IEntity performer, ActionType actionType, IEntity target) :
+            base(performer, actionType)
+        {
+            Target = target;
+        }
+    }
+}

Content.Shared/Actions/ITargetEntityItemAction.cs

@@ -0,0 +1,34 @@
+using System;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Serialization;
+using Robust.Shared.Map;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Item action which is used on a targeted entity.
+    /// </summary>
+    public interface ITargetEntityItemAction : IItemActionBehavior
+    {
+        /// <summary>
+        /// Invoked when the target entity action should be performed.
+        /// Implementation should perform the server side logic of the action.
+        /// </summary>
+        void DoTargetEntityAction(TargetEntityItemActionEventArgs args);
+    }
+
+    public class TargetEntityItemActionEventArgs : ItemActionEventArgs
+    {
+        /// <summary>
+        /// Entity being targeted
+        /// </summary>
+        public readonly IEntity Target;
+
+        public TargetEntityItemActionEventArgs(IEntity performer, IEntity target, IEntity item,
+            ItemActionType actionType) : base(performer, item, actionType)
+        {
+            Target = target;
+
+        }
+    }
+}

Content.Shared/Actions/ITargetPointAction.cs

@@ -0,0 +1,33 @@
+using System;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Map;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Action which requires the user to select a target point, which
+    /// does not necessarily have an entity on it.
+    /// </summary>
+    public interface ITargetPointAction : IActionBehavior
+    {
+        /// <summary>
+        /// Invoked when the target point action should be performed.
+        /// Implementation should perform the server side logic of the action.
+        /// </summary>
+        void DoTargetPointAction(TargetPointActionEventArgs args);
+    }
+
+    public class TargetPointActionEventArgs : ActionEventArgs
+    {
+        /// <summary>
+        /// Local coordinates of the targeted position.
+        /// </summary>
+        public readonly EntityCoordinates Target;
+
+        public TargetPointActionEventArgs(IEntity performer, EntityCoordinates target, ActionType actionType)
+            : base(performer, actionType)
+        {
+            Target = target;
+        }
+    }
+}

Content.Shared/Actions/ITargetPointItemAction.cs

@@ -0,0 +1,33 @@
+using System;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Map;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Item action which requires the user to select a target point, which
+    /// does not necessarily have an entity on it.
+    /// </summary>
+    public interface ITargetPointItemAction : IItemActionBehavior
+    {
+        /// <summary>
+        /// Invoked when the target point action should be performed.
+        /// Implementation should perform the server side logic of the action.
+        /// </summary>
+        void DoTargetPointAction(TargetPointItemActionEventArgs args);
+    }
+
+    public class TargetPointItemActionEventArgs : ItemActionEventArgs
+    {
+        /// <summary>
+        /// Local coordinates of the targeted position.
+        /// </summary>
+        public readonly EntityCoordinates Target;
+
+        public TargetPointItemActionEventArgs(IEntity performer, EntityCoordinates target, IEntity item,
+            ItemActionType actionType) : base(performer, item, actionType)
+        {
+            Target = target;
+        }
+    }
+}

Content.Shared/Actions/IToggleAction.cs

@@ -0,0 +1,41 @@
+using Robust.Shared.Interfaces.GameObjects;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Action which can be toggled on and off
+    /// </summary>
+    public interface IToggleAction : IActionBehavior
+    {
+        /// <summary>
+        /// Invoked when the action will be toggled on/off.
+        /// Implementation should perform the server side logic of whatever
+        /// happens when it is toggled on / off.
+        /// </summary>
+        /// <returns>true if the attempt to toggle was successful, meaning the state should be toggled to the desired value.
+        /// False to leave toggle status unchanged. This is NOT returning the new toggle status, it is only returning
+        /// whether the attempt to toggle to the indicated status was successful.
+        ///
+        /// Note that it's still okay if the implementation directly modifies toggle status via SharedActionsComponent,
+        /// this is just an additional level of safety to ensure implementations will always
+        /// explicitly indicate if the toggle status should be changed.</returns>
+        bool DoToggleAction(ToggleActionEventArgs args);
+    }
+
+    public class ToggleActionEventArgs : ActionEventArgs
+    {
+        /// <summary>
+        /// True if the toggle is attempting to be toggled on, false if attempting to toggle off
+        /// </summary>
+        public readonly bool ToggledOn;
+        /// <summary>
+        /// Opposite of ToggledOn
+        /// </summary>
+        public bool ToggledOff => !ToggledOn;
+
+        public ToggleActionEventArgs(IEntity performer, ActionType actionType, bool toggledOn) : base(performer, actionType)
+        {
+            ToggledOn = toggledOn;
+        }
+    }
+}

Content.Shared/Actions/IToggleItemAction.cs

@@ -0,0 +1,42 @@
+using Robust.Shared.Interfaces.GameObjects;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// Item action which can be toggled on and off
+    /// </summary>
+    public interface IToggleItemAction : IItemActionBehavior
+    {
+        /// <summary>
+        /// Invoked when the action will be toggled on/off.
+        /// Implementation should perform the server side logic of whatever
+        /// happens when it is toggled on / off.
+        /// </summary>
+        /// <returns>true if the attempt to toggle was successful, meaning the state should be toggled to the desired value.
+        /// False to leave toggle status unchanged. This is NOT returning the new toggle status, it is only returning
+        /// whether the attempt to toggle to the indicated status was successful.
+        ///
+        /// Note that it's still okay if the implementation directly modifies toggle status via ItemActionsComponent,
+        /// this is just an additional level of safety to ensure implementations will always
+        /// explicitly indicate if the toggle status should be changed.</returns>
+        bool DoToggleAction(ToggleItemActionEventArgs args);
+    }
+
+    public class ToggleItemActionEventArgs : ItemActionEventArgs
+    {
+        /// <summary>
+        /// True if the toggle was toggled on, false if it was toggled off
+        /// </summary>
+        public readonly bool ToggledOn;
+        /// <summary>
+        /// Opposite of ToggledOn
+        /// </summary>
+        public bool ToggledOff => !ToggledOn;
+
+        public ToggleItemActionEventArgs(IEntity performer, bool toggledOn, IEntity item,
+            ItemActionType actionType) : base(performer, item, actionType)
+        {
+            ToggledOn = toggledOn;
+        }
+    }
+}

Content.Shared/Actions/ItemActionPrototype.cs

@@ -0,0 +1,122 @@
+using Content.Shared.Interfaces;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization;
+using YamlDotNet.RepresentationModel;
+
+namespace Content.Shared.Actions
+{
+    /// <summary>
+    /// An action which is granted to an entity via an item (such as toggling a flashlight).
+    /// </summary>
+    [Prototype("itemAction")]
+    public class ItemActionPrototype : BaseActionPrototype
+    {
+        /// <summary>
+        /// Type of item action, no 2 itemAction prototypes should have the same one.
+        /// </summary>
+        public ItemActionType ActionType { get; private set; }
+
+        /// <see cref="ItemActionIconStyle"/>
+        public ItemActionIconStyle IconStyle { get; private set; }
+
+        /// <summary>
+        /// The IInstantItemAction that should be invoked when performing this
+        /// action. Null if this is not an Instant ActionBehaviorType.
+        /// Will be null on client side if the behavior is not in Content.Client.
+        /// </summary>
+        public IInstantItemAction InstantAction { get; private set; }
+
+        /// <summary>
+        /// The IToggleItemAction that should be invoked when performing this
+        /// action. Null if this is not a Toggle ActionBehaviorType.
+        /// Will be null on client side if the behavior is not in Content.Client.
+        /// </summary>
+        public IToggleItemAction ToggleAction { get; private set; }
+
+        /// <summary>
+        /// The ITargetEntityItemAction that should be invoked when performing this
+        /// action. Null if this is not a TargetEntity ActionBehaviorType.
+        /// Will be null on client side if the behavior is not in Content.Client.
+        /// </summary>
+        public ITargetEntityItemAction TargetEntityAction { get; private set; }
+
+        /// <summary>
+        /// The ITargetPointItemAction that should be invoked when performing this
+        /// action. Null if this is not a TargetPoint ActionBehaviorType.
+        /// Will be null on client side if the behavior is not in Content.Client.
+        /// </summary>
+        public ITargetPointItemAction TargetPointAction { get; private set; }
+
+        public override void LoadFrom(YamlMappingNode mapping)
+        {
+            base.LoadFrom(mapping);
+            var serializer = YamlObjectSerializer.NewReader(mapping);
+
+            serializer.DataField(this, x => x.ActionType, "actionType", ItemActionType.Error);
+            if (ActionType == ItemActionType.Error)
+            {
+                Logger.ErrorS("action", "missing or invalid actionType for action with name {0}", Name);
+            }
+
+            serializer.DataField(this, x => x.IconStyle, "iconStyle", ItemActionIconStyle.BigItem);
+
+            // TODO: Split this class into server/client after RobustToolbox#1405
+            if (IoCManager.Resolve<IModuleManager>().IsClientModule) return;
+
+            IItemActionBehavior behavior = null;
+            serializer.DataField(ref behavior, "behavior", null);
+            switch (behavior)
+            {
+                case null:
+                    BehaviorType = BehaviorType.None;
+                    Logger.ErrorS("action", "missing or invalid behavior for action with name {0}", Name);
+                    break;
+                case IInstantItemAction instantAction:
+                    ValidateBehaviorType(BehaviorType.Instant, typeof(IInstantItemAction));
+                    BehaviorType = BehaviorType.Instant;
+                    InstantAction = instantAction;
+                    break;
+                case IToggleItemAction toggleAction:
+                    ValidateBehaviorType(BehaviorType.Toggle, typeof(IToggleItemAction));
+                    BehaviorType = BehaviorType.Toggle;
+                    ToggleAction = toggleAction;
+                    break;
+                case ITargetEntityItemAction targetEntity:
+                    ValidateBehaviorType(BehaviorType.TargetEntity, typeof(ITargetEntityItemAction));
+                    BehaviorType = BehaviorType.TargetEntity;
+                    TargetEntityAction = targetEntity;
+                    break;
+                case ITargetPointItemAction targetPointAction:
+                    ValidateBehaviorType(BehaviorType.TargetPoint, typeof(ITargetPointItemAction));
+                    BehaviorType = BehaviorType.TargetPoint;
+                    TargetPointAction = targetPointAction;
+                    break;
+                default:
+                    BehaviorType = BehaviorType.None;
+                    Logger.ErrorS("action", "unrecognized behavior type for action with name {0}", Name);
+                    break;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Determines how the action icon appears in the hotbar for item actions.
+    /// </summary>
+    public enum ItemActionIconStyle : byte
+    {
+        /// <summary>
+        /// The default - the item icon will be big with a small action icon in the corner
+        /// </summary>
+        BigItem,
+        /// <summary>
+        /// The action icon will be big with a small item icon in the corner
+        /// </summary>
+        BigAction,
+        /// <summary>
+        /// BigAction but no item icon will be shown in the corner.
+        /// </summary>
+        NoItem
+    }
+}

Content.Shared/Alert/AlertManager.cs

@@ -1,6 +1,4 @@
 using System.Collections.Generic;
-using System.Linq;
-using Content.Shared.Prototypes.Kitchen;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Prototypes;
@@ -8,41 +6,28 @@ using Robust.Shared.Prototypes;
 namespace Content.Shared.Alert
 {
     /// <summary>
-    /// Provides access to all configured alerts. Ability to encode/decode a given state
-    /// to an int.
+    /// Provides access to all configured alerts by alert type.
     /// </summary>
     public class AlertManager
     {
         [Dependency]
         private readonly IPrototypeManager _prototypeManager = default!;
 
-        private AlertPrototype[] _orderedAlerts;
-        private Dictionary<AlertType, byte> _typeToIndex;
+        private Dictionary<AlertType, AlertPrototype> _typeToAlert;
 
         public void Initialize()
         {
-            // order by type value so we can map between the id and an integer index and use
-            // the index for compact alert change messages
-            _orderedAlerts =
-                _prototypeManager.EnumeratePrototypes<AlertPrototype>()
-                    .OrderBy(prototype => prototype.AlertType).ToArray();
-            _typeToIndex = new Dictionary<AlertType, byte>();
+            _typeToAlert = new Dictionary<AlertType, AlertPrototype>();
 
-            for (var i = 0; i < _orderedAlerts.Length; i++)
+            foreach (var alert in _prototypeManager.EnumeratePrototypes<AlertPrototype>())
             {
-                if (i > byte.MaxValue)
-                {
-                    Logger.ErrorS("alert", "too many alerts for byte encoding ({0})! encoding will need" +
-                                           " to be changed to use a ushort rather than byte", _typeToIndex.Count);
-                    break;
-                }
-                if (!_typeToIndex.TryAdd(_orderedAlerts[i].AlertType, (byte) i))
+                if (!_typeToAlert.TryAdd(alert.AlertType, alert))
                 {
                     Logger.ErrorS("alert",
-                        "Found alert with duplicate id {0}", _orderedAlerts[i].AlertType);
+                        "Found alert with duplicate alertType {0} - all alerts must have" +
+                        " a unique alerttype, this one will be skipped", alert.AlertType);
                 }
             }
-
         }
 
         /// <summary>
@@ -51,74 +36,7 @@ namespace Content.Shared.Alert
         /// <returns>true if found</returns>
         public bool TryGet(AlertType alertType, out AlertPrototype alert)
         {
-            if (_typeToIndex.TryGetValue(alertType, out var idx))
-            {
-                alert = _orderedAlerts[idx];
-                return true;
-            }
-
-            alert = null;
-            return false;
-        }
-
-        /// <summary>
-        /// Tries to get the alert of the indicated type along with its encoding
-        /// </summary>
-        /// <returns>true if found</returns>
-        public bool TryGetWithEncoded(AlertType alertType, out AlertPrototype alert, out byte encoded)
-        {
-            if (_typeToIndex.TryGetValue(alertType, out var idx))
-            {
-                alert = _orderedAlerts[idx];
-                encoded = (byte) idx;
-                return true;
-            }
-
-            alert = null;
-            encoded = 0;
-            return false;
-        }
-
-        /// <summary>
-        /// Tries to get the compact encoded representation of this alert
-        /// </summary>
-        /// <returns>true if successful</returns>
-        public bool TryEncode(AlertPrototype alert, out byte encoded)
-        {
-            return TryEncode(alert.AlertType, out encoded);
-        }
-
-        /// <summary>
-        /// Tries to get the compact encoded representation of the alert with
-        /// the indicated id
-        /// </summary>
-        /// <returns>true if successful</returns>
-        public bool TryEncode(AlertType alertType, out byte encoded)
-        {
-            if (_typeToIndex.TryGetValue(alertType, out var idx))
-            {
-                encoded = idx;
-                return true;
-            }
-
-            encoded = 0;
-            return false;
-        }
-
-        /// <summary>
-        /// Tries to get the alert from the encoded representation
-        /// </summary>
-        /// <returns>true if successful</returns>
-        public bool TryDecode(byte encodedAlert, out AlertPrototype alert)
-        {
-            if (encodedAlert >= _orderedAlerts.Length)
-            {
-                alert = null;
-                return false;
-            }
-
-            alert = _orderedAlerts[encodedAlert];
-            return true;
+            return _typeToAlert.TryGetValue(alertType, out alert);
         }
     }
 }

Content.Shared/Alert/AlertPrototype.cs

@@ -1,4 +1,6 @@
 using System;
+using Content.Shared.Interfaces;
+using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Prototypes;
 using Robust.Shared.Serialization;
@@ -70,6 +72,11 @@ namespace Content.Shared.Alert
         /// </summary>
         public bool SupportsSeverity => MaxSeverity != -1;
 
+        /// <summary>
+        /// Defines what to do when the alert is clicked.
+        /// </summary>
+        public IAlertClick OnClick { get; private set; }
+
         public void LoadFrom(YamlMappingNode mapping)
         {
             var serializer = YamlObjectSerializer.NewReader(mapping);
@@ -94,6 +101,9 @@ namespace Content.Shared.Alert
                 Category = alertCategory;
             }
             AlertKey = new AlertKey(AlertType, Category);
+
+            if (IoCManager.Resolve<IModuleManager>().IsClientModule) return;
+            serializer.DataField(this, x => x.OnClick, "onClick", null);
         }
 
         /// <param name="severity">severity level, if supported by this alert</param>
@@ -143,30 +153,26 @@ namespace Content.Shared.Alert
     [Serializable, NetSerializable]
     public struct AlertKey
     {
-        private readonly AlertType? _alertType;
-        private readonly AlertCategory? _alertCategory;
+        public readonly AlertType? AlertType;
+        public readonly AlertCategory? AlertCategory;
 
         /// NOTE: if the alert has a category you must pass the category for this to work
-        /// properly as a key. I.e. if the alert has a category and you pass only the ID, and you
-        /// compare this to another AlertKey that has both the category and the same ID, it will not consider them equal.
+        /// properly as a key. I.e. if the alert has a category and you pass only the alert type, and you
+        /// compare this to another AlertKey that has both the category and the same alert type, it will not consider them equal.
         public AlertKey(AlertType? alertType, AlertCategory? alertCategory)
         {
-            // if there is a category, ignore the alerttype.
-            if (alertCategory != null)
-            {
-                _alertCategory = alertCategory;
-                _alertType = null;
-            }
-            else
-            {
-                _alertCategory = null;
-                _alertType = alertType;
-            }
+            AlertCategory = alertCategory;
+            AlertType = alertType;
         }
 
         public bool Equals(AlertKey other)
         {
-            return _alertType == other._alertType && _alertCategory == other._alertCategory;
+            // compare only on alert category if we have one
+            if (AlertCategory.HasValue)
+            {
+                return other.AlertCategory == AlertCategory;
+            }
+            return AlertType == other.AlertType && AlertCategory == other.AlertCategory;
         }
 
         public override bool Equals(object obj)
@@ -176,11 +182,14 @@ namespace Content.Shared.Alert
 
         public override int GetHashCode()
         {
-            return HashCode.Combine(_alertType, _alertCategory);
+            // use only alert category if we have one
+            if (AlertCategory.HasValue) return AlertCategory.GetHashCode();
+            return AlertType.GetHashCode();
         }
 
         /// <param name="category">alert category, must not be null</param>
-        /// <returns>An alert key for the provided alert category</returns>
+        /// <returns>An alert key for the provided alert category. This must only be used for
+        /// queries and never storage, as it is lacking an alert type.</returns>
         public static AlertKey ForCategory(AlertCategory category)
         {
             return new(null, category);

Content.Shared/Alert/AlertType.cs

@@ -16,8 +16,10 @@
 
     /// <summary>
     /// Every kind of alert. Corresponds to alertType field in alert prototypes defined in YML
+    /// NOTE: Using byte for a compact encoding when sending this in messages, can upgrade
+    /// to ushort
     /// </summary>
-    public enum AlertType
+    public enum AlertType : byte
     {
         Error,
         LowPressure,

Content.Shared/Alert/IAlertClick.cs

@@ -0,0 +1,37 @@
+using System;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Serialization;
+
+namespace Content.Shared.Alert
+{
+    /// <summary>
+    /// Defines what should happen when an alert is clicked.
+    /// </summary>
+    public interface IAlertClick : IExposeData
+    {
+
+        /// <summary>
+        /// Invoked on server side when user clicks an alert.
+        /// </summary>
+        /// <param name="args"></param>
+        void AlertClicked(ClickAlertEventArgs args);
+    }
+
+    public class ClickAlertEventArgs : EventArgs
+    {
+        /// <summary>
+        /// Player clicking the alert
+        /// </summary>
+        public readonly IEntity Player;
+        /// <summary>
+        /// Alert that was clicked
+        /// </summary>
+        public readonly AlertPrototype Alert;
+
+        public ClickAlertEventArgs(IEntity player, AlertPrototype alert)
+        {
+            Player = player;
+            Alert = alert;
+        }
+    }
+}

Content.Shared/GameObjects/Components/Inventory/EquipmentSlotDefinitions.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Content.Shared.GameObjects.Components.Items;
 using JetBrains.Annotations;
 using Robust.Shared.Serialization;
 
@@ -26,7 +27,7 @@ namespace Content.Shared.GameObjects.Components.Inventory
         ///     Uniquely identifies a single slot in an inventory.
         /// </summary>
         [Serializable, NetSerializable]
-        public enum Slots
+        public enum Slots : byte
         {
             NONE = 0,
             HEAD,
@@ -148,6 +149,5 @@ namespace Content.Shared.GameObjects.Components.Inventory
             "Hands_left",
             "Hands_right",
         };
-
     }
 }

Content.Shared/GameObjects/Components/Inventory/SharedInventoryComponent.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Robust.Shared.GameObjects;
+using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.Interfaces.Reflection;
 using Robust.Shared.IoC;
 using Robust.Shared.Serialization;
@@ -47,6 +48,10 @@ namespace Content.Shared.GameObjects.Components.Inventory
             InventoryInstance = DynamicTypeFactory.CreateInstance<Inventory>(type);
         }
 
+        /// <returns>true if the item is equipped to an equip slot (NOT inside an equipped container
+        /// like inside a backpack)</returns>
+        public abstract bool IsEquipped(IEntity item);
+
         [Serializable, NetSerializable]
         protected class InventoryComponentState : ComponentState
         {

Content.Shared/GameObjects/Components/Items/SharedHandsComponent.cs

@@ -1,6 +1,7 @@
 #nullable enable
 using System;
 using Robust.Shared.GameObjects;
+using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.Serialization;
 
 namespace Content.Shared.GameObjects.Components.Items
@@ -9,6 +10,9 @@ namespace Content.Shared.GameObjects.Components.Items
     {
         public sealed override string Name => "Hands";
         public sealed override uint? NetID => ContentNetIDs.HANDS;
+
+        /// <returns>true if the item is in one of the hands</returns>
+        public abstract bool IsHolding(IEntity item);
     }
 
     [Serializable, NetSerializable]

Content.Shared/GameObjects/Components/Mobs/IActionAttempt.cs

@@ -0,0 +1,208 @@
+#nullable enable
+
+using Content.Shared.Actions;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Input.Binding;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Map;
+
+namespace Content.Shared.GameObjects.Components.Mobs
+{
+    /// <summary>
+    /// An attempt to perform a specific action. Main purpose of this interface is to
+    /// reduce code duplication related to handling attempts to perform non-item vs item actions by
+    /// providing a single interface for various functionality that needs to be performed on both.
+    /// </summary>
+    public interface IActionAttempt
+    {
+        /// <summary>
+        /// Action Prototype attempting to be performed
+        /// </summary>
+        BaseActionPrototype Action { get; }
+        ComponentMessage PerformInstantActionMessage();
+        ComponentMessage PerformToggleActionMessage(bool on);
+        ComponentMessage PerformTargetPointActionMessage(PointerInputCmdHandler.PointerInputCmdArgs args);
+        ComponentMessage PerformTargetEntityActionMessage(PointerInputCmdHandler.PointerInputCmdArgs args);
+        /// <summary>
+        /// Tries to get the action state for this action from the actionsComponent, returning
+        /// true if found.
+        /// </summary>
+        bool TryGetActionState(SharedActionsComponent actionsComponent, out ActionState actionState);
+
+        /// <summary>
+        /// Toggles the action within the provided action component
+        /// </summary>
+        void ToggleAction(SharedActionsComponent actionsComponent, bool toggleOn);
+
+        /// <summary>
+        /// Perform the server-side logic of the action
+        /// </summary>
+        void DoInstantAction(IEntity player);
+
+        /// <summary>
+        /// Perform the server-side logic of the toggle action
+        /// </summary>
+        /// <returns>true if the attempt to toggle was successful, meaning the state should be toggled to the
+        /// indicated value</returns>
+        bool DoToggleAction(IEntity player, bool on);
+
+        /// <summary>
+        /// Perform the server-side logic of the target point action
+        /// </summary>
+        void DoTargetPointAction(IEntity player, EntityCoordinates target);
+
+        /// <summary>
+        /// Perform the server-side logic of the target entity action
+        /// </summary>
+        void DoTargetEntityAction(IEntity player, IEntity target);
+    }
+
+    public class ActionAttempt : IActionAttempt
+    {
+        private readonly ActionPrototype _action;
+
+        public BaseActionPrototype Action => _action;
+
+        public ActionAttempt(ActionPrototype action)
+        {
+            _action = action;
+        }
+
+        public bool TryGetActionState(SharedActionsComponent actionsComponent, out ActionState actionState)
+        {
+            return actionsComponent.TryGetActionState(_action.ActionType, out actionState);
+        }
+
+        public void ToggleAction(SharedActionsComponent actionsComponent, bool toggleOn)
+        {
+            actionsComponent.ToggleAction(_action.ActionType, toggleOn);
+        }
+
+        public void DoInstantAction(IEntity player)
+        {
+            _action.InstantAction.DoInstantAction(new InstantActionEventArgs(player, _action.ActionType));
+        }
+
+        public bool DoToggleAction(IEntity player, bool on)
+        {
+            return _action.ToggleAction.DoToggleAction(new ToggleActionEventArgs(player, _action.ActionType, on));
+        }
+
+        public void DoTargetPointAction(IEntity player, EntityCoordinates target)
+        {
+            _action.TargetPointAction.DoTargetPointAction(new TargetPointActionEventArgs(player, target, _action.ActionType));
+        }
+
+        public void DoTargetEntityAction(IEntity player, IEntity target)
+        {
+            _action.TargetEntityAction.DoTargetEntityAction(new TargetEntityActionEventArgs(player, _action.ActionType,
+                target));
+        }
+
+        public ComponentMessage PerformInstantActionMessage()
+        {
+            return new PerformInstantActionMessage(_action.ActionType);
+        }
+
+        public ComponentMessage PerformToggleActionMessage(bool toggleOn)
+        {
+            if (toggleOn)
+            {
+                return new PerformToggleOnActionMessage(_action.ActionType);
+            }
+            return new PerformToggleOffActionMessage(_action.ActionType);
+        }
+
+        public ComponentMessage PerformTargetPointActionMessage(PointerInputCmdHandler.PointerInputCmdArgs args)
+        {
+            return new PerformTargetPointActionMessage(_action.ActionType, args.Coordinates);
+        }
+
+        public ComponentMessage PerformTargetEntityActionMessage(PointerInputCmdHandler.PointerInputCmdArgs args)
+        {
+            return new PerformTargetEntityActionMessage(_action.ActionType, args.EntityUid);
+        }
+
+        public override string ToString()
+        {
+            return $"{nameof(_action)}: {_action.ActionType}";
+        }
+    }
+
+    public class ItemActionAttempt : IActionAttempt
+    {
+        private readonly ItemActionPrototype _action;
+        private readonly IEntity _item;
+        private readonly ItemActionsComponent _itemActions;
+
+        public BaseActionPrototype Action => _action;
+
+        public ItemActionAttempt(ItemActionPrototype action, IEntity item, ItemActionsComponent itemActions)
+        {
+            _action = action;
+            _item = item;
+            _itemActions = itemActions;
+        }
+
+        public void DoInstantAction(IEntity player)
+        {
+            _action.InstantAction.DoInstantAction(new InstantItemActionEventArgs(player, _item, _action.ActionType));
+        }
+
+        public bool DoToggleAction(IEntity player, bool on)
+        {
+            return _action.ToggleAction.DoToggleAction(new ToggleItemActionEventArgs(player, on, _item, _action.ActionType));
+        }
+
+        public void DoTargetPointAction(IEntity player, EntityCoordinates target)
+        {
+            _action.TargetPointAction.DoTargetPointAction(new TargetPointItemActionEventArgs(player, target, _item,
+                _action.ActionType));
+        }
+
+        public void DoTargetEntityAction(IEntity player, IEntity target)
+        {
+            _action.TargetEntityAction.DoTargetEntityAction(new TargetEntityItemActionEventArgs(player, target,
+                _item, _action.ActionType));
+        }
+
+        public bool TryGetActionState(SharedActionsComponent actionsComponent, out ActionState actionState)
+        {
+            return actionsComponent.TryGetItemActionState(_action.ActionType, _item, out actionState);
+        }
+
+        public void ToggleAction(SharedActionsComponent actionsComponent, bool toggleOn)
+        {
+            _itemActions.Toggle(_action.ActionType, toggleOn);
+        }
+
+        public ComponentMessage PerformInstantActionMessage()
+        {
+            return new PerformInstantItemActionMessage(_action.ActionType, _item.Uid);
+        }
+
+        public ComponentMessage PerformToggleActionMessage(bool toggleOn)
+        {
+            if (toggleOn)
+            {
+                return new PerformToggleOnItemActionMessage(_action.ActionType, _item.Uid);
+            }
+            return new PerformToggleOffItemActionMessage(_action.ActionType, _item.Uid);
+        }
+
+        public ComponentMessage PerformTargetPointActionMessage(PointerInputCmdHandler.PointerInputCmdArgs args)
+        {
+            return new PerformTargetPointItemActionMessage(_action.ActionType, _item.Uid, args.Coordinates);
+        }
+
+        public ComponentMessage PerformTargetEntityActionMessage(PointerInputCmdHandler.PointerInputCmdArgs args)
+        {
+            return new PerformTargetEntityItemActionMessage(_action.ActionType, _item.Uid, args.EntityUid);
+        }
+
+        public override string ToString()
+        {
+            return $"{nameof(_action)}: {_action.ActionType}, {nameof(_item)}: {_item}";
+        }
+    }
+}

Content.Shared/GameObjects/Components/Mobs/ItemActionsComponent.cs

@@ -0,0 +1,249 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using Content.Shared.Actions;
+using Content.Shared.GameObjects.Components.Inventory;
+using Content.Shared.GameObjects.Components.Items;
+using Content.Shared.Interfaces.GameObjects.Components;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Serialization;
+using Robust.Shared.Log;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.GameObjects.Components.Mobs
+{
+    /// <summary>
+    /// This should be used on items which provide actions. Defines which actions the item provides
+    /// and allows modifying the states of those actions. Item components should use this rather than
+    /// SharedActionsComponent on the player to handle granting / revoking / modifying the states of the
+    /// actions provided by this item.
+    ///
+    /// When a player equips this item, all the actions defined in this component will be granted to the
+    /// player in their current states. This means the states will persist between players.
+    ///
+    /// Currently only maintained server side and not synced to client, as are all the equip/unequip events.
+    /// </summary>
+    [RegisterComponent]
+    public class ItemActionsComponent : Component, IEquippedHand, IEquipped, IUnequipped, IUnequippedHand
+    {
+        public override string Name => "ItemActions";
+
+        /// <summary>
+        /// Configuration for the item actions initially provided by this item. Actions defined here
+        /// will be automatically granted unless their state is modified using the methods
+        /// on this component. Additional actions can be granted by this item via GrantOrUpdate
+        /// </summary>
+        public IEnumerable<ItemActionConfig> ActionConfigs => _actionConfigs;
+
+        public bool IsEquipped => InSlot != EquipmentSlotDefines.Slots.NONE || InHand != null;
+        /// <summary>
+        /// Slot currently equipped to, NONE if not equipped to an equip slot.
+        /// </summary>
+        public EquipmentSlotDefines.Slots InSlot { get; private set; }
+        /// <summary>
+        /// hand it's currently in, null if not in a hand.
+        /// </summary>
+        public SharedHand? InHand { get; private set; }
+
+        /// <summary>
+        /// Entity currently holding this in hand or equip slot. Null if not held.
+        /// </summary>
+        public IEntity? Holder { get; private set; }
+        // cached actions component of the holder, since we'll need to access it frequently
+        private SharedActionsComponent? _holderActionsComponent;
+        private List<ItemActionConfig> _actionConfigs = new();
+        // State of all actions provided by this item.
+        private readonly Dictionary<ItemActionType, ActionState> _actions = new();
+
+
+        public override void ExposeData(ObjectSerializer serializer)
+        {
+            base.ExposeData(serializer);
+
+            serializer.DataField(ref _actionConfigs,"actions", new List<ItemActionConfig>());
+
+            foreach (var actionConfig in _actionConfigs)
+            {
+                GrantOrUpdate(actionConfig.ActionType, actionConfig.Enabled, false, null);
+            }
+        }
+
+        protected override void Startup()
+        {
+            base.Startup();
+            GrantOrUpdateAllToHolder();
+        }
+
+        protected override void Shutdown()
+        {
+            base.Shutdown();
+            RevokeAllFromHolder();
+        }
+
+        private void GrantOrUpdateAllToHolder()
+        {
+            if (_holderActionsComponent == null) return;
+            foreach (var (actionType, state) in _actions)
+            {
+                _holderActionsComponent.GrantOrUpdateItemAction(actionType, Owner.Uid, state);
+            }
+        }
+
+        private void RevokeAllFromHolder()
+        {
+            if (_holderActionsComponent == null) return;
+            foreach (var (actionType, state) in _actions)
+            {
+                _holderActionsComponent.RevokeItemAction(actionType, Owner.Uid);
+            }
+        }
+
+        /// <summary>
+        /// Update the state of the action, granting it if it isn't already granted.
+        /// If the action had any existing state, those specific fields will be overwritten by any
+        /// corresponding non-null arguments.
+        /// </summary>
+        /// <param name="actionType">action being granted / updated</param>
+        /// <param name="enabled">When null, preserves the current enable status of the action, defaulting
+        /// to true if action has no current state.
+        /// When non-null, indicates whether the entity is able to perform the action (if disabled,
+        /// the player will see they have the action but it will appear greyed out)</param>
+        /// <param name="toggleOn">When null, preserves the current toggle status of the action, defaulting
+        /// to false if action has no current state.
+        /// When non-null, action will be shown toggled to this value</param>
+        /// <param name="cooldown"> When null (unless clearCooldown is true), preserves the current cooldown status of the action, defaulting
+        /// to no cooldown if action has no current state.
+        /// When non-null or clearCooldown is true, action cooldown will be set to this value. Note that this cooldown
+        /// is tied to this item.</param>
+        /// <param name="clearCooldown"> If true, setting cooldown to null will clear the current cooldown
+        /// of this action rather than preserving it.</param>
+        public void GrantOrUpdate(ItemActionType actionType, bool? enabled = null,
+            bool? toggleOn = null,
+            (TimeSpan start, TimeSpan end)? cooldown = null, bool clearCooldown = false)
+        {
+            var dirty = false;
+            // this will be overwritten if we find the value in our dict, otherwise
+            // we will use this as our new action state.
+            if (!_actions.TryGetValue(actionType, out var actionState))
+            {
+                dirty = true;
+                actionState = new ActionState(enabled ?? true, toggleOn ?? false);
+            }
+
+            if (enabled.HasValue && enabled != actionState.Enabled)
+            {
+                dirty = true;
+                actionState.Enabled = true;
+            }
+
+            if ((cooldown.HasValue || clearCooldown) && actionState.Cooldown != cooldown)
+            {
+                dirty = true;
+                actionState.Cooldown = cooldown;
+            }
+
+            if (toggleOn.HasValue && actionState.ToggledOn != toggleOn.Value)
+            {
+                dirty = true;
+                actionState.ToggledOn = toggleOn.Value;
+            }
+
+            if (!dirty) return;
+
+            _actions[actionType] = actionState;
+            _holderActionsComponent?.GrantOrUpdateItemAction(actionType, Owner.Uid, actionState);
+        }
+
+        /// <summary>
+        /// Update the cooldown of a particular action. Actions on cooldown cannot be used.
+        /// Setting the cooldown to null clears it.
+        /// </summary>
+        public void Cooldown(ItemActionType actionType, (TimeSpan start, TimeSpan end)? cooldown = null)
+        {
+            GrantOrUpdate(actionType, cooldown: cooldown, clearCooldown: true);
+        }
+
+        /// <summary>
+        /// Enable / disable this action. Disabled actions are still shown to the player, but
+        /// shown as not usable.
+        /// </summary>
+        public void SetEnabled(ItemActionType actionType, bool enabled)
+        {
+            GrantOrUpdate(actionType, enabled);
+        }
+
+        /// <summary>
+        /// Toggle the action on / off
+        /// </summary>
+        public void Toggle(ItemActionType actionType, bool toggleOn)
+        {
+            GrantOrUpdate(actionType, toggleOn: toggleOn);
+        }
+
+        public void EquippedHand(EquippedHandEventArgs eventArgs)
+        {
+            // this entity cannot be granted actions if no actions component
+            if (!eventArgs.User.TryGetComponent<SharedActionsComponent>(out var actionsComponent))
+                return;
+            Holder = eventArgs.User;
+            _holderActionsComponent = actionsComponent;
+            InSlot = EquipmentSlotDefines.Slots.NONE;
+            InHand = eventArgs.Hand;
+            GrantOrUpdateAllToHolder();
+        }
+
+        public void Equipped(EquippedEventArgs eventArgs)
+        {
+            // this entity cannot be granted actions if no actions component
+            if (!eventArgs.User.TryGetComponent<SharedActionsComponent>(out var actionsComponent))
+                return;
+            Holder = eventArgs.User;
+            _holderActionsComponent = actionsComponent;
+            InSlot = eventArgs.Slot;
+            InHand = null;
+            GrantOrUpdateAllToHolder();
+        }
+
+        public void Unequipped(UnequippedEventArgs eventArgs)
+        {
+            RevokeAllFromHolder();
+            Holder = null;
+            _holderActionsComponent = null;
+            InSlot = EquipmentSlotDefines.Slots.NONE;
+            InHand = null;
+
+        }
+
+        public void UnequippedHand(UnequippedHandEventArgs eventArgs)
+        {
+            RevokeAllFromHolder();
+            Holder = null;
+            _holderActionsComponent = null;
+            InSlot = EquipmentSlotDefines.Slots.NONE;
+            InHand = null;
+        }
+    }
+
+    /// <summary>
+    /// Configuration for an item action provided by an item.
+    /// </summary>
+    public class ItemActionConfig : IExposeData
+    {
+        public ItemActionType ActionType { get; private set; }
+        /// <summary>
+        /// Whether action is initially enabled on this item. Defaults to true.
+        /// </summary>
+        public bool Enabled { get; private set; }
+
+        public void ExposeData(ObjectSerializer serializer)
+        {
+            serializer.DataField(this, x => x.ActionType, "actionType", ItemActionType.Error);
+            if (ActionType == ItemActionType.Error)
+            {
+                Logger.ErrorS("action", "invalid or missing actionType");
+            }
+            serializer.DataField(this, x => x.Enabled, "enabled", true);
+        }
+    }
+}

Content.Shared/GameObjects/Components/Mobs/SharedActionsComponent.cs

@@ -0,0 +1,652 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using Content.Shared.Actions;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Timing;
+using Robust.Shared.IoC;
+using Robust.Shared.Map;
+using Robust.Shared.Serialization;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Shared.GameObjects.Components.Mobs
+{
+    /// <summary>
+    /// Manages the actions available to an entity.
+    /// Should only be used for player-controlled entities.
+    ///
+    /// Actions are granted directly to the owner entity. Item actions are granted via a particular item which
+    /// must be in the owner's inventory (the action is revoked when item leaves the owner's inventory). This
+    /// should almost always be done via ItemActionsComponent on the item entity (which also tracks the
+    /// cooldowns associated with the actions on that item).
+    ///
+    /// Actions can still have an associated state even when revoked. For example, a flashlight toggle action
+    /// may be unusable while the player is stunned, but this component will still have an entry for the action
+    /// so the user can see whether it's currently toggled on or off.
+    /// </summary>
+    public abstract class SharedActionsComponent : Component
+    {
+        private static readonly TimeSpan CooldownExpiryThreshold = TimeSpan.FromSeconds(10);
+
+        [Dependency]
+        protected readonly ActionManager ActionManager = default!;
+        [Dependency]
+        protected readonly IGameTiming GameTiming = default!;
+        [Dependency]
+        protected readonly IEntityManager EntityManager = default!;
+
+        public override string Name => "Actions";
+        public override uint? NetID => ContentNetIDs.ACTIONS;
+
+        /// <summary>
+        /// Actions granted to this entity as soon as they spawn, regardless
+        /// of the status of the entity.
+        /// </summary>
+        public IEnumerable<ActionType> InnateActions => _innateActions ?? Enumerable.Empty<ActionType>();
+        private List<ActionType>? _innateActions;
+
+
+        // entries are removed from this if they are at the initial state (not enabled, no cooldown, toggled off).
+        // a system runs which periodically removes cooldowns from entries when they are revoked and their
+        // cooldowns have expired for a long enough time, also removing the entry if it is then at initial state.
+        // This helps to keep our component state smaller.
+        [ViewVariables]
+        private Dictionary<ActionType, ActionState> _actions = new();
+
+        // Holds item action states. Item actions are only added to this when granted, and are removed
+        // when revoked or when they leave inventory. This is almost entirely handled by ItemActionsComponent on
+        // item entities.
+        [ViewVariables]
+        private Dictionary<EntityUid, Dictionary<ItemActionType, ActionState>> _itemActions =
+            new();
+
+        public override void ExposeData(ObjectSerializer serializer)
+        {
+            base.ExposeData(serializer);
+            serializer.DataField(ref _innateActions,"innateActions", null);
+        }
+        protected override void Startup()
+        {
+            foreach (var actionType in InnateActions)
+            {
+                Grant(actionType);
+            }
+        }
+
+
+        public override ComponentState GetComponentState()
+        {
+            return new ActionComponentState(_actions, _itemActions);
+        }
+
+        public override void HandleComponentState(ComponentState? curState, ComponentState? nextState)
+        {
+            base.HandleComponentState(curState, nextState);
+
+            if (curState is not ActionComponentState state)
+            {
+                return;
+            }
+            _actions = state.Actions;
+            _itemActions = state.ItemActions;
+        }
+
+        /// <summary>
+        /// Gets the action state associated with the specified action type, if it has been
+        /// granted, has a cooldown, or has been toggled on
+        /// </summary>
+        /// <returns>false if not found for this action type</returns>
+        public bool TryGetActionState(ActionType actionType, out ActionState actionState)
+        {
+            return _actions.TryGetValue(actionType, out actionState);
+        }
+
+        /// <summary>
+        /// Gets the item action states associated with the specified item if any have been granted
+        /// and not yet revoked.
+        /// </summary>
+        /// <returns>false if no states found for this item action type.</returns>
+        public bool TryGetItemActionStates(EntityUid item, [NotNullWhen((true))] out IReadOnlyDictionary<ItemActionType, ActionState>? itemActionStates)
+        {
+            if (_itemActions.TryGetValue(item, out var actualItemActionStates))
+            {
+                itemActionStates = actualItemActionStates;
+                return true;
+            }
+
+            itemActionStates = null;
+            return false;
+        }
+
+        /// <seealso cref="TryGetItemActionStates(Robust.Shared.GameObjects.EntityUid,out System.Collections.Generic.IReadOnlyDictionary{Content.Shared.Actions.ItemActionType,Content.Shared.GameObjects.Components.Mobs.ActionState}?)"/>
+        public bool TryGetItemActionStates(IEntity item,
+            [NotNullWhen((true))] out IReadOnlyDictionary<ItemActionType, ActionState>? itemActionStates)
+        {
+            return TryGetItemActionStates(item.Uid, out itemActionStates);
+        }
+
+        /// <summary>
+        /// Gets the item action state associated with the specified item action type for the specified item, if it has any.
+        /// </summary>
+        /// <returns>false if no state found for this item action type for this item</returns>
+        public bool TryGetItemActionState(ItemActionType actionType, EntityUid item, out ActionState actionState)
+        {
+            if (_itemActions.TryGetValue(item, out var actualItemActionStates))
+            {
+                return actualItemActionStates.TryGetValue(actionType, out actionState);
+            }
+
+            actionState = default;
+            return false;
+        }
+
+        /// <returns>true if the action is granted and enabled (if item action, if granted and enabled for any item)</returns>
+        public bool IsGranted(BaseActionPrototype actionType)
+        {
+            return actionType switch
+            {
+                ActionPrototype actionPrototype => IsGranted(actionPrototype.ActionType),
+                ItemActionPrototype itemActionPrototype => IsGranted(itemActionPrototype.ActionType),
+                _ => false
+            };
+        }
+
+        public bool IsGranted(ActionType actionType)
+        {
+            if (TryGetActionState(actionType, out var actionState))
+            {
+                return actionState.Enabled;
+            }
+
+            return false;
+        }
+
+        /// <returns>true if the action is granted and enabled for any item. This
+        /// has to traverse the entire item state dictionary so please avoid frequent calls.</returns>
+        public bool IsGranted(ItemActionType actionType)
+        {
+            return _itemActions.Values.SelectMany(vals => vals)
+                .Any(state => state.Key == actionType && state.Value.Enabled);
+        }
+
+        /// <seealso cref="TryGetItemActionState(Content.Shared.Actions.ItemActionType,Robust.Shared.GameObjects.EntityUid,out Content.Shared.GameObjects.Components.Mobs.ActionState)"/>
+        public bool TryGetItemActionState(ItemActionType actionType, IEntity item, out ActionState actionState)
+        {
+            return TryGetItemActionState(actionType, item.Uid, out actionState);
+        }
+
+        /// <summary>
+        /// Gets all action types that have non-initial state (granted, have a cooldown, or toggled on).
+        /// </summary>
+        public IReadOnlyDictionary<ActionType, ActionState> ActionStates()
+        {
+            return _actions;
+        }
+
+        /// <summary>
+        /// Gets all items that have actions currently granted (that are not revoked
+        /// and still in inventory).
+        /// Map from item uid -> (action type -> associated action state)
+        /// PLEASE DO NOT MODIFY THE INNER DICTIONARY! I CANNOT CAST IT TO IReadOnlyDictionary!
+        /// </summary>
+        public IReadOnlyDictionary<EntityUid,Dictionary<ItemActionType, ActionState>> ItemActionStates()
+        {
+            return _itemActions;
+        }
+
+        /// <summary>
+        /// Creates or updates the action state with the supplied non-null values
+        /// </summary>
+        private void GrantOrUpdate(ActionType actionType, bool? enabled = null, bool? toggleOn = null,
+            (TimeSpan start, TimeSpan end)? cooldown = null, bool clearCooldown = false)
+        {
+            var dirty = false;
+            if (!_actions.TryGetValue(actionType, out var actionState))
+            {
+                // no state at all for this action, create it anew
+                dirty = true;
+                actionState = new ActionState(enabled ?? false, toggleOn ?? false);
+            }
+
+            if (enabled.HasValue && actionState.Enabled != enabled.Value)
+            {
+                dirty = true;
+                actionState.Enabled = enabled.Value;
+            }
+
+            if ((cooldown.HasValue || clearCooldown) && actionState.Cooldown != cooldown)
+            {
+                dirty = true;
+                actionState.Cooldown = cooldown;
+            }
+
+            if (toggleOn.HasValue && actionState.ToggledOn != toggleOn.Value)
+            {
+                dirty = true;
+                actionState.ToggledOn = toggleOn.Value;
+            }
+
+            if (!dirty) return;
+
+            _actions[actionType] = actionState;
+            AfterActionChanged();
+            Dirty();
+        }
+
+        /// <summary>
+        /// Intended to only be used by ItemActionsComponent.
+        /// Updates the state of the item action provided by the item, granting the action
+        /// if it is not yet granted to the player. Should be called whenever the
+        /// status changes. The existing state will be completely overwritten by the new state.
+        /// </summary>
+        public void GrantOrUpdateItemAction(ItemActionType actionType, EntityUid item, ActionState state)
+        {
+            if (!_itemActions.TryGetValue(item, out var itemStates))
+            {
+                itemStates = new Dictionary<ItemActionType, ActionState>();
+                _itemActions[item] = itemStates;
+            }
+
+            itemStates[actionType] = state;
+            AfterActionChanged();
+            Dirty();
+        }
+
+        /// <summary>
+        /// Intended to only be used by ItemActionsComponent. Revokes the item action so the player no longer
+        /// sees it and can no longer use it.
+        /// </summary>
+        public void RevokeItemAction(ItemActionType actionType, EntityUid item)
+        {
+            if (!_itemActions.TryGetValue(item, out var itemStates))
+                return;
+
+            itemStates.Remove(actionType);
+            AfterActionChanged();
+            Dirty();
+        }
+
+        /// <summary>
+        /// Grants the entity the ability to perform the action, optionally overriding its
+        /// current state with specified values.
+        ///
+        /// Even if the action was already granted, if the action had any state (cooldown, toggle) prior to this method
+        /// being called, it will be preserved, with specific fields optionally overridden by any of the provided
+        /// non-null arguments.
+        /// </summary>
+        /// <param name="toggleOn">When null, preserves the current toggle status of the action, defaulting
+        /// to false if action has no current state.
+        /// When non-null, action will be shown toggled to this value</param>
+        /// <param name="cooldown"> When null, preserves the current cooldown status of the action, defaulting
+        /// to no cooldown if action has no current state.
+        /// When non-null, action cooldown will be set to this value.</param>
+        public void Grant(ActionType actionType, bool? toggleOn = null,
+            (TimeSpan start, TimeSpan end)? cooldown = null)
+        {
+           GrantOrUpdate(actionType, true, toggleOn, cooldown);
+        }
+
+        /// <summary>
+        /// Grants the entity the ability to perform the action, resetting its state
+        /// to its initial state and settings its state based on supplied parameters.
+        ///
+        /// Even if the action was already granted, if the action had any state (cooldown, toggle) prior to this method
+        /// being called, it will be reset to initial (no cooldown, toggled off).
+        /// </summary>
+        /// <param name="toggleOn">action will be shown toggled to this value</param>
+        /// <param name="cooldown">action cooldown will be set to this value (by default the cooldown is cleared).</param>
+        public void GrantFromInitialState(ActionType actionType, bool toggleOn = false,
+            (TimeSpan start, TimeSpan end)? cooldown = null)
+        {
+            _actions.Remove(actionType);
+            Grant(actionType, toggleOn, cooldown);
+        }
+
+        /// <summary>
+        /// Sets the cooldown for the action. Actions on cooldown cannot be used.
+        ///
+        /// This will work even if the action is revoked -
+        /// for example if there's an ability with a cooldown which is temporarily unusable due
+        /// to the player being stunned, the cooldown will still tick down even while the player
+        /// is stunned.
+        ///
+        /// Setting cooldown to null clears it.
+        /// </summary>
+        public void Cooldown(ActionType actionType, (TimeSpan start, TimeSpan end)? cooldown)
+        {
+            GrantOrUpdate(actionType, cooldown: cooldown, clearCooldown: true);
+        }
+
+        /// <summary>
+        /// Revokes the ability to perform the action for this entity. Current state
+        /// of the action (toggle / cooldown) is preserved.
+        /// </summary>
+        public void Revoke(ActionType actionType)
+        {
+            if (!_actions.TryGetValue(actionType, out var actionState)) return;
+
+            if (!actionState.Enabled) return;
+
+            actionState.Enabled = false;
+
+            // don't store it anymore if its at its initial state.
+            if (actionState.IsAtInitialState)
+            {
+                _actions.Remove(actionType);
+            }
+            else
+            {
+                _actions[actionType] = actionState;
+            }
+
+            AfterActionChanged();
+            Dirty();
+        }
+
+        /// <summary>
+        /// Toggles the action to the specified value. Works even if the action is on cooldown
+        /// or revoked.
+        /// </summary>
+        public void ToggleAction(ActionType actionType, bool toggleOn)
+        {
+            Grant(actionType, toggleOn);
+        }
+
+        /// <summary>
+        /// Clears any cooldowns which have expired beyond the predefined threshold.
+        /// this should be run periodically to ensure we don't have unbounded growth of
+        /// our saved action data, and keep our component state sent to the client as minimal as possible.
+        /// </summary>
+        public void ExpireCooldowns()
+        {
+
+            // actions - only clear cooldowns and remove associated action state
+            // if the action is at initial state
+            var actionTypesToRemove = new List<ActionType>();
+            foreach (var (actionType, actionState) in _actions)
+            {
+                // ignore it unless we may be able to delete it due to
+                // clearing the cooldown
+                if (!actionState.IsAtInitialStateExceptCooldown) continue;
+                if (!actionState.Cooldown.HasValue)
+                {
+                    actionTypesToRemove.Add(actionType);
+                    continue;
+                }
+                var expiryTime = GameTiming.CurTime - actionState.Cooldown.Value.Item2;
+                if (expiryTime > CooldownExpiryThreshold)
+                {
+                    actionTypesToRemove.Add(actionType);
+                }
+            }
+
+            foreach (var remove in actionTypesToRemove)
+            {
+                _actions.Remove(remove);
+            }
+        }
+
+        /// <summary>
+        /// Invoked after a change has been made to an action state in this component.
+        /// </summary>
+        protected virtual void AfterActionChanged() { }
+    }
+
+    [Serializable, NetSerializable]
+    public class ActionComponentState : ComponentState
+    {
+        public Dictionary<ActionType, ActionState> Actions;
+        public Dictionary<EntityUid, Dictionary<ItemActionType, ActionState>> ItemActions;
+
+        public ActionComponentState(Dictionary<ActionType, ActionState> actions,
+            Dictionary<EntityUid, Dictionary<ItemActionType, ActionState>> itemActions) : base(ContentNetIDs.ACTIONS)
+        {
+            Actions = actions;
+            ItemActions = itemActions;
+        }
+    }
+
+    [Serializable, NetSerializable]
+    public struct ActionState
+    {
+        /// <summary>
+        /// False if this action is not currently allowed to be performed.
+        /// </summary>
+        public bool Enabled;
+        /// <summary>
+        /// Only used for toggle actions, indicates whether it's currently toggled on or off
+        /// TODO: Eventually this should probably be a byte so we it can toggle through multiple states.
+        /// </summary>
+        public bool ToggledOn;
+        public (TimeSpan start, TimeSpan end)? Cooldown;
+        public bool IsAtInitialState => IsAtInitialStateExceptCooldown && !Cooldown.HasValue;
+        public bool IsAtInitialStateExceptCooldown => !Enabled && !ToggledOn;
+
+        /// <summary>
+        /// Creates an action state for the indicated type, defaulting to the
+        /// initial state.
+        /// </summary>
+        public ActionState(bool enabled = false, bool toggledOn = false, (TimeSpan start, TimeSpan end)? cooldown = null)
+        {
+            Enabled = enabled;
+            ToggledOn = toggledOn;
+            Cooldown = cooldown;
+        }
+
+        public bool IsOnCooldown(TimeSpan curTime)
+        {
+            if (Cooldown == null) return false;
+            return curTime < Cooldown.Value.Item2;
+        }
+        public bool IsOnCooldown(IGameTiming gameTiming)
+        {
+            return IsOnCooldown(gameTiming.CurTime);
+        }
+
+        public bool Equals(ActionState other)
+        {
+            return Enabled == other.Enabled && ToggledOn == other.ToggledOn && Nullable.Equals(Cooldown, other.Cooldown);
+        }
+
+        public override bool Equals(object? obj)
+        {
+            return obj is ActionState other && Equals(other);
+        }
+
+        public override int GetHashCode()
+        {
+            return HashCode.Combine(Enabled, ToggledOn, Cooldown);
+        }
+    }
+
+    [Serializable, NetSerializable]
+    public abstract class BasePerformActionMessage : ComponentMessage
+    {
+        public abstract BehaviorType BehaviorType { get; }
+    }
+
+    [Serializable, NetSerializable]
+    public abstract class PerformActionMessage : BasePerformActionMessage
+    {
+        public readonly ActionType ActionType;
+
+        protected PerformActionMessage(ActionType actionType)
+        {
+            Directed = true;
+            ActionType = actionType;
+        }
+    }
+
+    [Serializable, NetSerializable]
+    public abstract class PerformItemActionMessage : BasePerformActionMessage
+    {
+        public readonly ItemActionType ActionType;
+        public readonly EntityUid Item;
+
+        protected PerformItemActionMessage(ItemActionType actionType, EntityUid item)
+        {
+            Directed = true;
+            ActionType = actionType;
+            Item = item;
+        }
+    }
+
+
+    /// <summary>
+    /// A message that tells server we want to run the instant action logic.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public class PerformInstantActionMessage : PerformActionMessage
+    {
+        public override BehaviorType BehaviorType => BehaviorType.Instant;
+
+        public PerformInstantActionMessage(ActionType actionType) : base(actionType)
+        {
+        }
+    }
+
+    /// <summary>
+    /// A message that tells server we want to run the instant action logic.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public class PerformInstantItemActionMessage : PerformItemActionMessage
+    {
+        public override BehaviorType BehaviorType => BehaviorType.Instant;
+
+        public PerformInstantItemActionMessage(ItemActionType actionType, EntityUid item) : base(actionType, item)
+        {
+        }
+    }
+
+    public interface IToggleActionMessage
+    {
+        bool ToggleOn { get; }
+    }
+
+    public interface ITargetPointActionMessage
+    {
+        /// <summary>
+        /// Targeted local coordinates
+        /// </summary>
+        EntityCoordinates Target { get; }
+    }
+
+    public interface ITargetEntityActionMessage
+    {
+        /// <summary>
+        /// Targeted entity
+        /// </summary>
+        EntityUid Target { get; }
+    }
+
+    /// <summary>
+    /// A message that tells server we want to toggle on the indicated action.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public class PerformToggleOnActionMessage : PerformActionMessage, IToggleActionMessage
+    {
+        public override BehaviorType BehaviorType => BehaviorType.Toggle;
+        public bool ToggleOn => true;
+        public PerformToggleOnActionMessage(ActionType actionType) : base(actionType) { }
+    }
+
+    /// <summary>
+    /// A message that tells server we want to toggle off the indicated action.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public class PerformToggleOffActionMessage : PerformActionMessage, IToggleActionMessage
+    {
+        public override BehaviorType BehaviorType => BehaviorType.Toggle;
+        public bool ToggleOn => false;
+        public PerformToggleOffActionMessage(ActionType actionType) : base(actionType) { }
+    }
+
+    /// <summary>
+    /// A message that tells server we want to toggle on the indicated action.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public class PerformToggleOnItemActionMessage : PerformItemActionMessage, IToggleActionMessage
+    {
+        public override BehaviorType BehaviorType => BehaviorType.Toggle;
+        public bool ToggleOn => true;
+        public PerformToggleOnItemActionMessage(ItemActionType actionType, EntityUid item) : base(actionType, item) { }
+    }
+
+    /// <summary>
+    /// A message that tells server we want to toggle off the indicated action.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public class PerformToggleOffItemActionMessage : PerformItemActionMessage, IToggleActionMessage
+    {
+        public override BehaviorType BehaviorType => BehaviorType.Toggle;
+        public bool ToggleOn => false;
+        public PerformToggleOffItemActionMessage(ItemActionType actionType, EntityUid item) : base(actionType, item) { }
+    }
+
+    /// <summary>
+    /// A message that tells server we want to target the provided point with a particular action.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public class PerformTargetPointActionMessage : PerformActionMessage, ITargetPointActionMessage
+    {
+        public override BehaviorType BehaviorType => BehaviorType.TargetPoint;
+        private readonly EntityCoordinates _target;
+        public EntityCoordinates Target => _target;
+
+        public PerformTargetPointActionMessage(ActionType actionType, EntityCoordinates target) : base(actionType)
+        {
+            _target = target;
+        }
+    }
+
+    /// <summary>
+    /// A message that tells server we want to target the provided point with a particular action.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public class PerformTargetPointItemActionMessage : PerformItemActionMessage, ITargetPointActionMessage
+    {
+        private readonly EntityCoordinates _target;
+        public EntityCoordinates Target => _target;
+        public override BehaviorType BehaviorType => BehaviorType.TargetPoint;
+
+        public PerformTargetPointItemActionMessage(ItemActionType actionType, EntityUid item, EntityCoordinates target) : base(actionType, item)
+        {
+            _target = target;
+        }
+    }
+
+    /// <summary>
+    /// A message that tells server we want to target the provided entity with a particular action.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public class PerformTargetEntityActionMessage : PerformActionMessage, ITargetEntityActionMessage
+    {
+        public override BehaviorType BehaviorType => BehaviorType.TargetEntity;
+        private readonly EntityUid _target;
+        public EntityUid Target => _target;
+
+        public PerformTargetEntityActionMessage(ActionType actionType, EntityUid target) : base(actionType)
+        {
+            _target = target;
+        }
+    }
+
+    /// <summary>
+    /// A message that tells server we want to target the provided entity with a particular action.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public class PerformTargetEntityItemActionMessage : PerformItemActionMessage, ITargetEntityActionMessage
+    {
+        public override BehaviorType BehaviorType => BehaviorType.TargetEntity;
+        private readonly EntityUid _target;
+        public EntityUid Target => _target;
+
+        public PerformTargetEntityItemActionMessage(ItemActionType actionType, EntityUid item, EntityUid target) : base(actionType, item)
+        {
+            _target = target;
+        }
+    }
+}

Content.Shared/GameObjects/Components/Mobs/SharedAlertsComponent.cs

@@ -1,13 +1,10 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using Content.Shared.Alert;
 using Robust.Shared.GameObjects;
-using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Serialization;
-using Robust.Shared.Utility;
 using Robust.Shared.ViewVariables;
 
 namespace Content.Shared.GameObjects.Components.Mobs
@@ -18,16 +15,30 @@ namespace Content.Shared.GameObjects.Components.Mobs
     /// </summary>
     public abstract class SharedAlertsComponent : Component
     {
-        private static readonly AlertState[] NO_ALERTS = new AlertState[0];
-
         [Dependency]
         protected readonly AlertManager AlertManager = default!;
 
-        public override string Name => "AlertsUI";
+        public override string Name => "Alerts";
         public override uint? NetID => ContentNetIDs.ALERTS;
 
-        [ViewVariables]
-        private Dictionary<AlertKey, ClickableAlertState> _alerts = new();
+        [ViewVariables] private Dictionary<AlertKey, AlertState> _alerts = new();
+
+        public override void HandleComponentState(ComponentState curState, ComponentState nextState)
+        {
+            base.HandleComponentState(curState, nextState);
+
+            if (curState is not AlertsComponentState state)
+            {
+                return;
+            }
+
+            _alerts = state.Alerts;
+        }
+
+        public override ComponentState GetComponentState()
+        {
+            return new AlertsComponentState(_alerts);
+        }
 
         /// <returns>true iff an alert of the indicated alert category is currently showing</returns>
         public bool IsShowingAlertCategory(AlertCategory alertCategory)
@@ -53,82 +64,14 @@ namespace Content.Shared.GameObjects.Components.Mobs
             return _alerts.ContainsKey(alertKey);
         }
 
-        protected IEnumerable<AlertState> EnumerateAlertStates()
+        protected IEnumerable<KeyValuePair<AlertKey, AlertState>> EnumerateAlertStates()
         {
-            return _alerts.Values.Select(alertData => alertData.AlertState);
-        }
-
-        /// <summary>
-        /// Invokes the alert's specified callback if there is one.
-        /// Not intended to be used on clientside.
-        /// </summary>
-        protected void PerformAlertClickCallback(AlertPrototype alert, IEntity owner)
-        {
-            if (_alerts.TryGetValue(alert.AlertKey, out var alertStateCallback))
-            {
-                alertStateCallback.OnClickAlert?.Invoke(new ClickAlertEventArgs(owner, alert));
-            }
-            else
-            {
-                Logger.DebugS("alert", "player {0} attempted to invoke" +
-                                       " alert click for {1} but that alert is not currently" +
-                                       " showing", owner.Name, alert.AlertType);
-            }
-        }
-
-        /// <summary>
-        /// Creates a new array containing all of the current alert states.
-        /// </summary>
-        /// <returns></returns>
-        protected AlertState[] CreateAlertStatesArray()
-        {
-            if (_alerts.Count == 0) return NO_ALERTS;
-            var states = new AlertState[_alerts.Count];
-            // because I don't trust LINQ
-            var idx = 0;
-            foreach (var alertData in _alerts.Values)
-            {
-                states[idx++] = alertData.AlertState;
-            }
-
-            return states;
+            return _alerts;
         }
 
         protected bool TryGetAlertState(AlertKey key, out AlertState alertState)
         {
-            if (_alerts.TryGetValue(key, out var alertData))
-            {
-                alertState = alertData.AlertState;
-                return true;
-            }
-
-            alertState = default;
-            return false;
-        }
-
-        /// <summary>
-        /// Replace the current active alerts with the specified alerts. Any
-        /// OnClickAlert callbacks on the active alerts will be erased.
-        /// </summary>
-        protected void SetAlerts(AlertState[] alerts)
-        {
-            var newAlerts = new Dictionary<AlertKey, ClickableAlertState>();
-            foreach (var alertState in alerts)
-            {
-                if (AlertManager.TryDecode(alertState.AlertEncoded, out var alert))
-                {
-                    newAlerts[alert.AlertKey] = new ClickableAlertState
-                    {
-                        AlertState = alertState
-                    };
-                }
-                else
-                {
-                    Logger.ErrorS("alert", "unrecognized encoded alert {0}", alertState.AlertEncoded);
-                }
-            }
-
-            _alerts = newAlerts;
+            return _alerts.TryGetValue(key, out alertState);
         }
 
         /// <summary>
@@ -136,30 +79,24 @@ namespace Content.Shared.GameObjects.Components.Mobs
         /// it will be updated / replaced with the specified values.
         /// </summary>
         /// <param name="alertType">type of the alert to set</param>
-        /// <param name="onClickAlert">callback to invoke when ClickAlertMessage is received by the server
-        /// after being clicked by client. Has no effect when specified on the clientside.</param>
         /// <param name="severity">severity, if supported by the alert</param>
         /// <param name="cooldown">cooldown start and end, if null there will be no cooldown (and it will
         /// be erased if there is currently a cooldown for the alert)</param>
-        public void ShowAlert(AlertType alertType, short? severity = null, OnClickAlert onClickAlert = null,
-            ValueTuple<TimeSpan, TimeSpan>? cooldown = null)
+        public void ShowAlert(AlertType alertType, short? severity = null, ValueTuple<TimeSpan, TimeSpan>? cooldown = null)
         {
-            if (AlertManager.TryGetWithEncoded(alertType, out var alert, out var encoded))
+            if (AlertManager.TryGet(alertType, out var alert))
             {
                 if (_alerts.TryGetValue(alert.AlertKey, out var alertStateCallback) &&
-                    alertStateCallback.AlertState.AlertEncoded == encoded &&
-                    alertStateCallback.AlertState.Severity == severity && alertStateCallback.AlertState.Cooldown == cooldown)
+                    alert.AlertType == alertType &&
+                    alertStateCallback.Severity == severity && alertStateCallback.Cooldown == cooldown)
                 {
-                    alertStateCallback.OnClickAlert = onClickAlert;
                     return;
                 }
 
-                _alerts[alert.AlertKey] = new ClickableAlertState
-                {
-                    AlertState = new AlertState
-                        {Cooldown = cooldown, AlertEncoded = encoded, Severity = severity},
-                    OnClickAlert = onClickAlert
-                };
+                _alerts[alert.AlertKey] = new AlertState
+                    {Cooldown = cooldown, Severity = severity};
+
+                AfterShowAlert();
 
                 Dirty();
 
@@ -212,7 +149,12 @@ namespace Content.Shared.GameObjects.Components.Mobs
         }
 
         /// <summary>
-        /// Invoked after clearing an alert prior to dirtying the control
+        /// Invoked after showing an alert prior to dirtying the component
+        /// </summary>
+        protected virtual void AfterShowAlert() { }
+
+        /// <summary>
+        /// Invoked after clearing an alert prior to dirtying the component
         /// </summary>
         protected virtual void AfterClearAlert() { }
     }
@@ -220,9 +162,9 @@ namespace Content.Shared.GameObjects.Components.Mobs
     [Serializable, NetSerializable]
     public class AlertsComponentState : ComponentState
     {
-        public AlertState[] Alerts;
+        public Dictionary<AlertKey, AlertState> Alerts;
 
-        public AlertsComponentState(AlertState[] alerts) : base(ContentNetIDs.ALERTS)
+        public AlertsComponentState(Dictionary<AlertKey, AlertState> alerts) : base(ContentNetIDs.ALERTS)
         {
             Alerts = alerts;
         }
@@ -234,46 +176,19 @@ namespace Content.Shared.GameObjects.Components.Mobs
     [Serializable, NetSerializable]
     public class ClickAlertMessage : ComponentMessage
     {
-        public readonly byte EncodedAlert;
+        public readonly AlertType AlertType;
 
-        public ClickAlertMessage(byte encodedAlert)
+        public ClickAlertMessage(AlertType alertType)
         {
             Directed = true;
-            EncodedAlert = encodedAlert;
+            AlertType = alertType;
         }
     }
 
     [Serializable, NetSerializable]
     public struct AlertState
     {
-        public byte AlertEncoded;
         public short? Severity;
         public ValueTuple<TimeSpan, TimeSpan>? Cooldown;
     }
-
-    public struct ClickableAlertState
-    {
-        public AlertState AlertState;
-        public OnClickAlert OnClickAlert;
-    }
-
-    public delegate void OnClickAlert(ClickAlertEventArgs args);
-
-    public class ClickAlertEventArgs : EventArgs
-    {
-        /// <summary>
-        /// Player clicking the alert
-        /// </summary>
-        public readonly IEntity Player;
-        /// <summary>
-        /// Alert that was clicked
-        /// </summary>
-        public readonly AlertPrototype Alert;
-
-        public ClickAlertEventArgs(IEntity player, AlertPrototype alert)
-        {
-            Player = player;
-            Alert = alert;
-        }
-    }
 }

Content.Shared/GameObjects/Components/Pulling/SharedPullerComponent.cs

@@ -69,17 +69,11 @@ namespace Content.Shared.GameObjects.Components.Pulling
             {
                 case PullStartedMessage msg:
                     Pulling = msg.Pulled.Owner;
-                    if (ownerStatus != null)
-                    {
-                        ownerStatus.ShowAlert(AlertType.Pulling, onClickAlert: OnClickAlert);
-                    }
+                    ownerStatus?.ShowAlert(AlertType.Pulling);
                     break;
                 case PullStoppedMessage _:
                     Pulling = null;
-                    if (ownerStatus != null)
-                    {
-                        ownerStatus.ClearAlert(AlertType.Pulling);
-                    }
+                    ownerStatus?.ClearAlert(AlertType.Pulling);
                     break;
             }
         }

Content.Shared/GameObjects/ContentNetIDs.cs

@@ -86,7 +86,8 @@
         public const uint SINGULARITY = 1080;
         public const uint CHARACTERINFO = 1081;
         public const uint REAGENT_GRINDER = 1082;
-        public const uint DAMAGEABLE = 1083;
+        public const uint ACTIONS = 1083;
+        public const uint DAMAGEABLE = 1084;
 
         // Net IDs for integration tests.
         public const uint PREDICTION_TEST = 10001;

Content.Shared/GameObjects/EntitySystems/SharedActionSystem.cs

@@ -0,0 +1,30 @@
+using Content.Shared.GameObjects.Components.Mobs;
+using Content.Shared.Interfaces.GameObjects.Components;
+using Robust.Shared.GameObjects.Systems;
+
+namespace Content.Shared.GameObjects.EntitySystems
+{
+    /// <summary>
+    /// Evicts action states with expired cooldowns.
+    /// </summary>
+    public class SharedActionSystem : EntitySystem
+    {
+        private const float CooldownCheckIntervalSeconds = 10;
+        private float _timeSinceCooldownCheck;
+
+
+        public override void Update(float frameTime)
+        {
+            base.Update(frameTime);
+
+            _timeSinceCooldownCheck += frameTime;
+            if (_timeSinceCooldownCheck < CooldownCheckIntervalSeconds) return;
+
+            foreach (var comp in ComponentManager.EntityQuery<SharedActionsComponent>(false))
+            {
+                comp.ExpireCooldowns();
+            }
+            _timeSinceCooldownCheck -= CooldownCheckIntervalSeconds;
+        }
+    }
+}

Content.Shared/Input/ContentKeyFunctions.cs

@@ -41,5 +41,16 @@ namespace Content.Shared.Input
         public static readonly BoundKeyFunction Arcade1 = "Arcade1";
         public static readonly BoundKeyFunction Arcade2 = "Arcade2";
         public static readonly BoundKeyFunction Arcade3 = "Arcade3";
+        public static readonly BoundKeyFunction OpenActionsMenu = "OpenAbilitiesMenu";
+        public static readonly BoundKeyFunction Hotbar0 = "Hotbar0";
+        public static readonly BoundKeyFunction Hotbar1 = "Hotbar1";
+        public static readonly BoundKeyFunction Hotbar2 = "Hotbar2";
+        public static readonly BoundKeyFunction Hotbar3 = "Hotbar3";
+        public static readonly BoundKeyFunction Hotbar4 = "Hotbar4";
+        public static readonly BoundKeyFunction Hotbar5 = "Hotbar5";
+        public static readonly BoundKeyFunction Hotbar6 = "Hotbar6";
+        public static readonly BoundKeyFunction Hotbar7 = "Hotbar7";
+        public static readonly BoundKeyFunction Hotbar8 = "Hotbar8";
+        public static readonly BoundKeyFunction Hotbar9 = "Hotbar9";
     }
 }

Content.Shared/Interfaces/GameObjects/Components/Interaction/IActivate.cs

@@ -6,8 +6,11 @@ using Robust.Shared.Interfaces.GameObjects;
 namespace Content.Shared.Interfaces.GameObjects.Components
 {
     /// <summary>
-    ///     This interface gives components behavior when being activated in the world when the user
-    ///     is in range and has unobstructed access to the target entity (allows inside blockers).
+    ///     This interface gives components behavior when being activated (by default,
+    ///     this is done via the "E" key) when the user is in range and has unobstructed access to the target entity
+    ///     (allows inside blockers). This includes activating an object in the world as well as activating an
+    ///     object in inventory. Unlike IUse, this can be performed on entities that aren't in the active hand,
+    ///     even when the active hand is currently holding something else.
     /// </summary>
     public interface IActivate
     {

Content.Shared/Interfaces/GameObjects/Components/Interaction/IAfterInteract.cs

@@ -7,8 +7,9 @@ using Robust.Shared.Map;
 namespace Content.Shared.Interfaces.GameObjects.Components
 {
     /// <summary>
-    /// This interface gives components a behavior when clicking on another object and no interaction occurs,
-    /// at any range.
+    /// This interface gives components a behavior when their entity is in the active hand, when
+    /// clicking on another object and no interaction occurs, at any range. This includes
+    /// clicking on an object in the world as well as clicking on an object in inventory.
     /// </summary>
     public interface IAfterInteract
     {

Content.Shared/Interfaces/GameObjects/Components/Interaction/IEquipped.cs

@@ -7,22 +7,35 @@ using Robust.Shared.Interfaces.GameObjects;
 namespace Content.Shared.Interfaces.GameObjects.Components
 {
     /// <summary>
-    ///     This interface gives components behavior when their owner is put in an inventory slot.
+    ///     This interface gives components behavior when their entity is put in a non-hand inventory slot,
+    ///     regardless of where it came from.  This includes moving the entity from a hand slot into a non-hand slot
+    ///     (which would also fire <see cref="IUnequippedHand"/>).
+    ///
+    ///     This DOES NOT fire when putting the entity into a hand slot (<see cref="IEquippedHand"/>), nor
+    ///     does it fire when putting the entity into held/equipped storage.
     /// </summary>
     public interface IEquipped
     {
         void Equipped(EquippedEventArgs eventArgs);
     }
 
-    public class EquippedEventArgs : EventArgs
+    public abstract class UserEventArgs : EventArgs
     {
-        public EquippedEventArgs(IEntity user, EquipmentSlotDefines.Slots slot)
+        public IEntity User { get; }
+
+        protected UserEventArgs(IEntity user)
         {
             User = user;
+        }
+    }
+
+    public class EquippedEventArgs : UserEventArgs
+    {
+        public EquippedEventArgs(IEntity user, EquipmentSlotDefines.Slots slot) : base(user)
+        {
             Slot = slot;
         }
 
-        public IEntity User { get; }
         public EquipmentSlotDefines.Slots Slot { get; }
     }
 

Content.Shared/Interfaces/GameObjects/Components/Interaction/IEquippedHand.cs

@@ -0,0 +1,64 @@
+using System;
+using Content.Shared.GameObjects.Components.Inventory;
+using Content.Shared.GameObjects.Components.Items;
+using JetBrains.Annotations;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Interfaces.GameObjects;
+
+namespace Content.Shared.Interfaces.GameObjects.Components
+{
+    /// <summary>
+    ///     This interface gives components behavior when their entity is put in a hand inventory slot,
+    ///     even if it came from another hand slot (which would also fire <see cref="IUnequippedHand"/>).
+    ///     This includes moving the entity from a non-hand slot into a hand slot
+    ///     (which would also fire <see cref="IUnequipped"/>).
+    /// </summary>
+    public interface IEquippedHand
+    {
+        void EquippedHand(EquippedHandEventArgs eventArgs);
+    }
+
+    public class EquippedHandEventArgs : UserEventArgs
+    {
+        public EquippedHandEventArgs(IEntity user, SharedHand hand) : base(user)
+        {
+            Hand = hand;
+        }
+
+        public SharedHand Hand { get; }
+    }
+
+    /// <summary>
+    ///     Raised when putting the entity into a hand slot
+    /// </summary>
+    [PublicAPI]
+    public class EquippedHandMessage : EntitySystemMessage
+    {
+        /// <summary>
+        ///     If this message has already been "handled" by a previous system.
+        /// </summary>
+        public bool Handled { get; set; }
+
+        /// <summary>
+        ///     Entity that equipped the item.
+        /// </summary>
+        public IEntity User { get; }
+
+        /// <summary>
+        ///     Item that was equipped.
+        /// </summary>
+        public IEntity Equipped { get; }
+
+        /// <summary>
+        ///     Hand the item is going into.
+        /// </summary>
+        public SharedHand Hand { get; }
+
+        public EquippedHandMessage(IEntity user, IEntity equipped, SharedHand hand)
+        {
+            User = user;
+            Equipped = equipped;
+            Hand = hand;
+        }
+    }
+}

Content.Shared/Interfaces/GameObjects/Components/Interaction/IInteractUsing.cs

@@ -8,8 +8,9 @@ using Robust.Shared.Map;
 namespace Content.Shared.Interfaces.GameObjects.Components
 {
     /// <summary>
-    /// This interface gives components behavior when being clicked on by a user with an object in their hand
-    /// who is in range and has unobstructed reach of the target entity (allows inside blockers).
+    /// This interface gives components behavior when their entity is clicked on by a user with an object in their hand
+    /// who is in range and has unobstructed reach of the target entity (allows inside blockers). This includes
+    /// clicking on an object in the world as well as clicking on an object in inventory.
     /// </summary>
     public interface IInteractUsing
     {

Content.Shared/Interfaces/GameObjects/Components/Interaction/IUnequipped.cs

@@ -7,22 +7,25 @@ using Robust.Shared.Interfaces.GameObjects;
 namespace Content.Shared.Interfaces.GameObjects.Components
 {
     /// <summary>
-    ///     This interface gives components behavior when their owner is removed from an inventory slot.
+    ///     This interface gives components behavior when their entity is removed from a non-hand inventory slot,
+    ///     regardless of where it's going to. This includes moving the entity from a non-hand slot into a hand slot
+    ///     (which would also fire <see cref="IEquippedHand"/>).
+    ///
+    ///     This DOES NOT fire when removing the entity from a hand slot (<see cref="IUnequippedHand"/>), nor
+    ///     does it fire when removing the entity from held/equipped storage.
     /// </summary>
     public interface IUnequipped
     {
         void Unequipped(UnequippedEventArgs eventArgs);
     }
 
-    public class UnequippedEventArgs : EventArgs
+    public class UnequippedEventArgs : UserEventArgs
     {
-        public UnequippedEventArgs(IEntity user, EquipmentSlotDefines.Slots slot)
+        public UnequippedEventArgs(IEntity user, EquipmentSlotDefines.Slots slot) : base(user)
         {
-            User = user;
             Slot = slot;
         }
 
-        public IEntity User { get; }
         public EquipmentSlotDefines.Slots Slot { get; }
     }
 
@@ -43,19 +46,19 @@ namespace Content.Shared.Interfaces.GameObjects.Components
         public IEntity User { get; }
 
         /// <summary>
-        ///     Item that was equipped.
+        ///     Item that was unequipped.
         /// </summary>
-        public IEntity Equipped { get; }
+        public IEntity Unequipped { get; }
 
         /// <summary>
         ///     Slot where the item was removed from.
         /// </summary>
         public EquipmentSlotDefines.Slots Slot { get; }
 
-        public UnequippedMessage(IEntity user, IEntity equipped, EquipmentSlotDefines.Slots slot)
+        public UnequippedMessage(IEntity user, IEntity unequipped, EquipmentSlotDefines.Slots slot)
         {
             User = user;
-            Equipped = equipped;
+            Unequipped = unequipped;
             Slot = slot;
         }
     }

Content.Shared/Interfaces/GameObjects/Components/Interaction/IUnequippedHand.cs

@@ -0,0 +1,63 @@
+using System;
+using Content.Shared.GameObjects.Components.Inventory;
+using Content.Shared.GameObjects.Components.Items;
+using JetBrains.Annotations;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Interfaces.GameObjects;
+
+namespace Content.Shared.Interfaces.GameObjects.Components
+{
+    /// <summary>
+    ///     This interface gives components behavior when their entity is removed from a hand slot,
+    ///     even if it is going into another hand slot (which would also fire <see cref="IEquippedHand"/>).
+    ///     This includes moving the entity from a hand slot into a non-hand slot (which would also fire <see cref="IEquipped"/>).
+    /// </summary>
+    public interface IUnequippedHand
+    {
+        void UnequippedHand(UnequippedHandEventArgs eventArgs);
+    }
+
+    public class UnequippedHandEventArgs : UserEventArgs
+    {
+        public UnequippedHandEventArgs(IEntity user, SharedHand hand) : base(user)
+        {
+            Hand = hand;
+        }
+
+        public SharedHand Hand { get; }
+    }
+
+    /// <summary>
+    ///     Raised when removing the entity from an inventory slot.
+    /// </summary>
+    [PublicAPI]
+    public class UnequippedHandMessage : EntitySystemMessage
+    {
+        /// <summary>
+        ///     If this message has already been "handled" by a previous system.
+        /// </summary>
+        public bool Handled { get; set; }
+
+        /// <summary>
+        ///     Entity that equipped the item.
+        /// </summary>
+        public IEntity User { get; }
+
+        /// <summary>
+        ///     Item that was unequipped.
+        /// </summary>
+        public IEntity Unequipped { get; }
+
+        /// <summary>
+        ///     Hand the item is removed from.
+        /// </summary>
+        public SharedHand Hand { get; }
+
+        public UnequippedHandMessage(IEntity user, IEntity unequipped, SharedHand hand)
+        {
+            User = user;
+            Unequipped = unequipped;
+            Hand = hand;
+        }
+    }
+}

Content.Shared/Interfaces/GameObjects/Components/Interaction/IUse.cs

@@ -6,7 +6,8 @@ using Robust.Shared.Interfaces.GameObjects;
 namespace Content.Shared.Interfaces.GameObjects.Components
 {
     /// <summary>
-    /// This interface gives components behavior when using the entity in your hands
+    /// This interface gives components behavior when using the entity in your active hand
+    /// (done by clicking the entity in the active hand or pressing the keybind that defaults to Z).
     /// </summary>
     public interface IUse
     {

Content.Shared/Utility/Cooldowns.cs

@@ -0,0 +1,28 @@
+using System;
+using Robust.Shared.Interfaces.Timing;
+using Robust.Shared.IoC;
+
+namespace Content.Shared.Utility
+{
+    /// <summary>
+    /// Utilities for working with cooldowns.
+    /// </summary>
+    public static class Cooldowns
+    {
+        /// <param name="gameTiming">game timing to use, otherwise will resolve using IoCManager.</param>
+        /// <returns>a cooldown interval starting at GameTiming.Curtime and ending at (offset) from CurTime.
+        /// For example, passing TimeSpan.FromSeconds(5) will create an interval
+        /// from now to 5 seconds from now.</returns>
+        public static (TimeSpan start, TimeSpan end) FromNow(TimeSpan offset, IGameTiming gameTiming = null)
+        {
+            var now = (gameTiming ?? IoCManager.Resolve<IGameTiming>()).CurTime;
+            return (now, now + offset);
+        }
+
+        /// <see cref="FromNow"/>
+        public static (TimeSpan start, TimeSpan end) SecondsFromNow(double seconds, IGameTiming gameTiming = null)
+        {
+            return FromNow(TimeSpan.FromSeconds(seconds), gameTiming);
+        }
+    }
+}

Content.Tests/Server/GameObjects/Components/Mobs/ServerAlertsComponentTests.cs

@@ -1,14 +1,10 @@
 using System.IO;
-using System.Linq;
 using Content.Server.GameObjects.Components.Mobs;
 using Content.Shared.Alert;
 using Content.Shared.GameObjects.Components.Mobs;
-using Content.Shared.Utility;
 using NUnit.Framework;
-using Robust.Shared.GameObjects;
 using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.IoC;
-using Robust.Shared.Map;
 using Robust.Shared.Prototypes;
 
 namespace Content.Tests.Server.GameObjects.Components.Mobs
@@ -48,23 +44,23 @@ namespace Content.Tests.Server.GameObjects.Components.Mobs
             var alertsComponent = new ServerAlertsComponent();
             alertsComponent = IoCManager.InjectDependencies(alertsComponent);
 
-            Assert.That(alertManager.TryGetWithEncoded(AlertType.LowPressure, out var lowpressure, out var lpencoded));
-            Assert.That(alertManager.TryGetWithEncoded(AlertType.HighPressure, out var highpressure, out var hpencoded));
+            Assert.That(alertManager.TryGet(AlertType.LowPressure, out var lowpressure));
+            Assert.That(alertManager.TryGet(AlertType.HighPressure, out var highpressure));
 
             alertsComponent.ShowAlert(AlertType.LowPressure);
             var alertState = alertsComponent.GetComponentState() as AlertsComponentState;
             Assert.NotNull(alertState);
-            Assert.That(alertState.Alerts.Length, Is.EqualTo(1));
-            Assert.That(alertState.Alerts[0], Is.EqualTo(new AlertState{AlertEncoded = lpencoded}));
+            Assert.That(alertState.Alerts.Count, Is.EqualTo(1));
+            Assert.That(alertState.Alerts.ContainsKey(lowpressure.AlertKey));
 
             alertsComponent.ShowAlert(AlertType.HighPressure);
             alertState = alertsComponent.GetComponentState() as AlertsComponentState;
-            Assert.That(alertState.Alerts.Length, Is.EqualTo(1));
-            Assert.That(alertState.Alerts[0], Is.EqualTo(new AlertState{AlertEncoded = hpencoded}));
+            Assert.That(alertState.Alerts.Count, Is.EqualTo(1));
+            Assert.That(alertState.Alerts.ContainsKey(highpressure.AlertKey));
 
             alertsComponent.ClearAlertCategory(AlertCategory.Pressure);
             alertState = alertsComponent.GetComponentState() as AlertsComponentState;
-            Assert.That(alertState.Alerts.Length, Is.EqualTo(0));
+            Assert.That(alertState.Alerts.Count, Is.EqualTo(0));
         }
     }
 }

Content.Tests/Shared/Alert/AlertManagerTests.cs

@@ -37,25 +37,10 @@ namespace Content.Tests.Shared.Alert
             Assert.That(alertManager.TryGet(AlertType.HighPressure, out var highPressure));
             Assert.That(highPressure.IconPath, Is.EqualTo("/Textures/Interface/Alerts/Pressure/highpressure.png"));
 
-            Assert.That(alertManager.TryGetWithEncoded(AlertType.LowPressure, out lowPressure, out var encodedLowPressure));
+            Assert.That(alertManager.TryGet(AlertType.LowPressure, out lowPressure));
             Assert.That(lowPressure.IconPath, Is.EqualTo("/Textures/Interface/Alerts/Pressure/lowpressure.png"));
-            Assert.That(alertManager.TryGetWithEncoded(AlertType.HighPressure, out highPressure, out var encodedHighPressure));
+            Assert.That(alertManager.TryGet(AlertType.HighPressure, out highPressure));
             Assert.That(highPressure.IconPath, Is.EqualTo("/Textures/Interface/Alerts/Pressure/highpressure.png"));
-
-            Assert.That(alertManager.TryEncode(lowPressure, out var encodedLowPressure2));
-            Assert.That(encodedLowPressure2, Is.EqualTo(encodedLowPressure));
-            Assert.That(alertManager.TryEncode(highPressure, out var encodedHighPressure2));
-            Assert.That(encodedHighPressure2, Is.EqualTo(encodedHighPressure));
-            Assert.That(encodedLowPressure, Is.Not.EqualTo(encodedHighPressure));
-
-            Assert.That(alertManager.TryDecode(encodedLowPressure, out var decodedLowPressure));
-            Assert.That(decodedLowPressure, Is.EqualTo(lowPressure));
-            Assert.That(alertManager.TryDecode(encodedHighPressure, out var decodedHighPressure));
-            Assert.That(decodedHighPressure, Is.EqualTo(highPressure));
-
-            Assert.False(alertManager.TryEncode(AlertType.Debug1, out _));
-            Assert.False(alertManager.TryGetWithEncoded(AlertType.Debug1, out _, out _));
-
         }
     }
 }

Content.Tests/Shared/Alert/AlertPrototypeTests.cs

@@ -1,9 +1,13 @@
 using System.IO;
+using Content.Server.Utility;
 using Content.Shared.Alert;
+using Content.Shared.Interfaces;
 using NUnit.Framework;
 using Robust.Shared.Interfaces.Log;
+using Robust.Shared.Interfaces.Reflection;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
+using Robust.Shared.Serialization;
 using Robust.Shared.Utility;
 using Robust.UnitTesting;
 using YamlDotNet.RepresentationModel;
@@ -22,7 +26,6 @@ namespace Content.Tests.Shared.Alert
   minSeverity: 0
   maxSeverity: 6";
 
-
         [Test]
         public void TestAlertKey()
         {