Refactor standing to be ECS (#4142)

* Refactor standing to be ECS

E C S B A B Y

* DONE

* FIX IT FIX IT FIX IT

* IsDown event

* Change to methods

* Fixes

* Address some reviews

* Last of the Mohicans

* Final fixes

* Fix tests

Content.Client/MobState/States/DeadMobState.cs

@@ -1,6 +1,6 @@
-using Content.Client.Standing;
+using Content.Shared.MobState;
-using Content.Shared.MobState;
 using Content.Shared.MobState.State;
+using Content.Shared.Standing;
 using Robust.Client.GameObjects;
 using Robust.Shared.GameObjects;
 
@@ -16,25 +16,6 @@ namespace Content.Client.MobState.States
             {
                 appearance.SetData(DamageStateVisuals.State, DamageState.Dead);
             }
-
-            EntitySystem.Get<StandingStateSystem>().Down(entity);
-
-            if (entity.TryGetComponent(out PhysicsComponent? physics))
-            {
-                physics.CanCollide = false;
-            }
-        }
-
-        public override void ExitState(IEntity entity)
-        {
-            base.ExitState(entity);
-
-            EntitySystem.Get<StandingStateSystem>().Standing(entity);
-
-            if (entity.TryGetComponent(out PhysicsComponent? physics))
-            {
-                physics.CanCollide = true;
-            }
         }
     }
 }

Content.Client/MobState/States/NormalMobState.cs

@@ -7,14 +7,5 @@ namespace Content.Client.MobState.States
 {
     public class NormalMobState : SharedNormalMobState
     {
-        public override void EnterState(IEntity entity)
-        {
-            base.EnterState(entity);
-
-            if (entity.TryGetComponent(out AppearanceComponent? appearance))
-            {
-                appearance.SetData(DamageStateVisuals.State, DamageState.Alive);
-            }
-        }
     }
 }

Content.Client/Standing/StandingStateSystem.cs

@@ -1,42 +0,0 @@
-using Content.Shared.Rotation;
-using Content.Shared.Standing;
-using Robust.Client.GameObjects;
-using Robust.Shared.GameObjects;
-
-namespace Content.Client.Standing
-{
-    public class StandingStateSystem : SharedStandingStateSystem
-    {
-        protected override bool OnDown(IEntity entity, bool playSound = true, bool dropItems = true, bool force = false)
-        {
-            if (!entity.TryGetComponent(out AppearanceComponent? appearance))
-            {
-                return false;
-            }
-
-            var newState = RotationState.Horizontal;
-            appearance.TryGetData<RotationState>(RotationVisuals.RotationState, out var oldState);
-
-            if (newState != oldState)
-            {
-                appearance.SetData(RotationVisuals.RotationState, newState);
-            }
-
-            return true;
-        }
-
-        protected override bool OnStand(IEntity entity)
-        {
-            if (!entity.TryGetComponent(out AppearanceComponent? appearance)) return false;
-
-            appearance.TryGetData<RotationState>(RotationVisuals.RotationState, out var oldState);
-            var newState = RotationState.Vertical;
-
-            if (newState == oldState) return false;
-
-            appearance.SetData(RotationVisuals.RotationState, newState);
-
-            return true;
-        }
-    }
-}

Content.IntegrationTests/Tests/Body/LegTest.cs

@@ -27,6 +27,7 @@ namespace Content.IntegrationTests.Tests.Body
     template: HumanoidTemplate
     preset: HumanPreset
     centerSlot: torso
+  - type: StandingState
 ";
 
         [Test]

Content.IntegrationTests/Tests/Buckle/BuckleTest.cs

@@ -39,6 +39,7 @@ namespace Content.IntegrationTests.Tests.Buckle
     template: HumanoidTemplate
     preset: HumanPreset
     centerSlot: torso
+  - type: StandingState
 
 - type: entity
   name: {StrapDummyId}

Content.Server/Buckle/Components/BuckleComponent.cs

@@ -5,14 +5,13 @@ using Content.Server.Alert;
 using Content.Server.Hands.Components;
 using Content.Server.MobState.States;
 using Content.Server.Pulling;
-using Content.Server.Standing;
 using Content.Server.Stunnable.Components;
 using Content.Shared.ActionBlocker;
 using Content.Shared.Alert;
 using Content.Shared.Buckle.Components;
-using Content.Shared.Interaction.Events;
 using Content.Shared.Interaction.Helpers;
 using Content.Shared.Notification.Managers;
+using Content.Shared.Standing;
 using Content.Shared.Verbs;
 using Robust.Server.GameObjects;
 using Robust.Shared.Audio;
@@ -130,12 +129,12 @@ namespace Content.Server.Buckle.Components
                     ownTransform.WorldRotation = strapTransform.WorldRotation;
                     break;
                 case StrapPosition.Stand:
-                    EntitySystem.Get<StandingStateSystem>().Standing(Owner);
+                    EntitySystem.Get<StandingStateSystem>().Stand(Owner);
                     ownTransform.WorldRotation = strapTransform.WorldRotation;
                     break;
                 case StrapPosition.Down:
-                    EntitySystem.Get<StandingStateSystem>().Down(Owner, force: true);
+                    EntitySystem.Get<StandingStateSystem>().Down(Owner, false, false);
-                    ownTransform.WorldRotation = Angle.South;
+                    ownTransform.LocalRotation = Angle.Zero;
                     break;
             }
 
@@ -343,7 +342,7 @@ namespace Content.Server.Buckle.Components
             }
             else
             {
-                EntitySystem.Get<StandingStateSystem>().Standing(Owner);
+                EntitySystem.Get<StandingStateSystem>().Stand(Owner);
             }
 
             _mobState?.CurrentState?.EnterState(Owner);

Content.Server/Hands/HandsSystem.cs

@@ -50,6 +50,18 @@ namespace Content.Server.Hands
             CommandBinds.Unregister<HandsSystem>();
         }
 
+        protected override void DropAllItemsInHands(IEntity entity, bool doMobChecks = true)
+        {
+            base.DropAllItemsInHands(entity, doMobChecks);
+
+            if (!entity.TryGetComponent(out IHandsComponent? hands)) return;
+
+            foreach (var heldItem in hands.GetAllHeldItems())
+            {
+                hands.Drop(heldItem.Owner, doMobChecks, intentional:false);
+            }
+        }
+
         //TODO: Actually shows all items/clothing/etc.
         private void HandleExamined(EntityUid uid, HandsComponent component, ExaminedEvent args)
         {

Content.Server/Instruments/InstrumentComponent.cs

@@ -1,7 +1,6 @@
 #nullable enable
 using System;
 using System.Linq;
-using Content.Server.Standing;
 using Content.Server.Stunnable.Components;
 using Content.Server.UserInterface;
 using Content.Shared.ActionBlocker;
@@ -9,8 +8,8 @@ using Content.Shared.DragDrop;
 using Content.Shared.Hands;
 using Content.Shared.Instruments;
 using Content.Shared.Interaction;
-using Content.Shared.Interaction.Events;
 using Content.Shared.Notification.Managers;
+using Content.Shared.Standing;
 using Content.Shared.Throwing;
 using Robust.Server.GameObjects;
 using Robust.Server.Player;
@@ -357,7 +356,7 @@ namespace Content.Server.Instruments
                 if (mob != null)
                 {
                     if (Handheld)
-                        EntitySystem.Get<StandingStateSystem>().DropAllItemsInHands(mob, false);
+                        EntitySystem.Get<StandingStateSystem>().Down(mob, false);
 
                     if (mob.TryGetComponent(out StunnableComponent? stun))
                     {

Content.Server/MobState/States/CriticalMobState.cs

@@ -1,8 +1,5 @@
-using Content.Server.Standing;
+using Content.Server.Stunnable.Components;
-using Content.Server.Stunnable.Components;
-using Content.Shared.MobState;
 using Content.Shared.MobState.State;
-using Robust.Server.GameObjects;
 using Robust.Shared.GameObjects;
 
 namespace Content.Server.MobState.States
@@ -13,17 +10,10 @@ namespace Content.Server.MobState.States
         {
             base.EnterState(entity);
 
-            if (entity.TryGetComponent(out AppearanceComponent? appearance))
-            {
-                appearance.SetData(DamageStateVisuals.State, DamageState.Critical);
-            }
-
             if (entity.TryGetComponent(out StunnableComponent? stun))
             {
                 stun.CancelAll();
             }
-
-            EntitySystem.Get<StandingStateSystem>().Down(entity);
         }
     }
 }

Content.Server/MobState/States/DeadMobState.cs

@@ -1,5 +1,4 @@
 using Content.Server.Alert;
-using Content.Server.Standing;
 using Content.Server.Stunnable.Components;
 using Content.Shared.Alert;
 using Content.Shared.MobState;
@@ -15,11 +14,6 @@ namespace Content.Server.MobState.States
         {
             base.EnterState(entity);
 
-            if (entity.TryGetComponent(out AppearanceComponent? appearance))
-            {
-                appearance.SetData(DamageStateVisuals.State, DamageState.Dead);
-            }
-
             if (entity.TryGetComponent(out ServerAlertsComponent? status))
             {
                 status.ShowAlert(AlertType.HumanDead);
@@ -29,8 +23,6 @@ namespace Content.Server.MobState.States
             {
                 stun.CancelAll();
             }
-
-            EntitySystem.Get<StandingStateSystem>().Down(entity);
         }
     }
 }

Content.Server/MobState/States/NormalMobState.cs

@@ -1,29 +1,15 @@
 #nullable enable
 using Content.Server.Alert;
-using Content.Server.Standing;
 using Content.Shared.Alert;
 using Content.Shared.Damage.Components;
 using Content.Shared.MobState;
 using Content.Shared.MobState.State;
-using Robust.Server.GameObjects;
 using Robust.Shared.GameObjects;
 
 namespace Content.Server.MobState.States
 {
     public class NormalMobState : SharedNormalMobState
     {
-        public override void EnterState(IEntity entity)
-        {
-            base.EnterState(entity);
-
-            EntitySystem.Get<StandingStateSystem>().Standing(entity);
-
-            if (entity.TryGetComponent(out AppearanceComponent? appearance))
-            {
-                appearance.SetData(DamageStateVisuals.State, DamageState.Alive);
-            }
-        }
-
         public override void UpdateState(IEntity entity, int threshold)
         {
             base.UpdateState(entity, threshold);

Content.Server/Morgue/Components/BodyBagEntityStorageComponent.cs

@@ -3,15 +3,14 @@ using System.Threading.Tasks;
 using Content.Server.Hands.Components;
 using Content.Server.Items;
 using Content.Server.Paper;
-using Content.Server.Standing;
 using Content.Server.Storage.Components;
 using Content.Shared.ActionBlocker;
 using Content.Shared.Body.Components;
 using Content.Shared.Examine;
 using Content.Shared.Interaction;
-using Content.Shared.Interaction.Events;
 using Content.Shared.Morgue;
 using Content.Shared.Notification.Managers;
+using Content.Shared.Standing;
 using Content.Shared.Verbs;
 using Robust.Server.GameObjects;
 using Robust.Shared.Containers;
@@ -39,7 +38,7 @@ namespace Content.Server.Morgue.Components
         {
             base.Initialize();
             _appearance?.SetData(BodyBagVisuals.Label, false);
-            LabelContainer = ContainerHelpers.EnsureContainer<ContainerSlot>(Owner, "body_bag_label", out _);
+            LabelContainer = Owner.EnsureContainer<ContainerSlot>("body_bag_label", out _);
         }
 
         protected override bool AddToContents(IEntity entity)

Content.Server/Morgue/Components/CrematoriumEntityStorageComponent.cs

@@ -131,11 +131,11 @@ namespace Content.Server.Morgue.Components
             }
 
             victim.PopupMessageOtherClients(Loc.GetString("crematorium-entity-storage-component-suicide-message-others", ("victim", victim)));
-            EntitySystem.Get<SharedStandingStateSystem>().Down(victim, false, false, true);
 
             if (CanInsert(victim))
             {
                 Insert(victim);
+                EntitySystem.Get<StandingStateSystem>().Down(victim, false);
             }
             else
             {

Content.Server/Morgue/Components/MorgueEntityStorageComponent.cs

@@ -1,5 +1,4 @@
 #nullable enable
-using Content.Server.Standing;
 using Content.Server.Storage.Components;
 using Content.Shared.Body.Components;
 using Content.Shared.Directions;
@@ -9,6 +8,7 @@ using Content.Shared.Interaction.Helpers;
 using Content.Shared.Morgue;
 using Content.Shared.Notification.Managers;
 using Content.Shared.Physics;
+using Content.Shared.Standing;
 using Robust.Server.GameObjects;
 using Robust.Shared.Audio;
 using Robust.Shared.Containers;
@@ -51,7 +51,7 @@ namespace Content.Server.Morgue.Components
         {
             base.Initialize();
             Appearance?.SetData(MorgueVisuals.Open, false);
-            TrayContainer = ContainerHelpers.EnsureContainer<ContainerSlot>(Owner, "morgue_tray", out _);
+            TrayContainer = Owner.EnsureContainer<ContainerSlot>("morgue_tray", out _);
         }
 
         public override Vector2 ContentsDumpPosition()

Content.Server/Standing/StandingStateSystem.cs

@@ -1,83 +0,0 @@
-#nullable enable
-using Content.Server.Hands.Components;
-using Content.Shared.Audio;
-using Content.Shared.Rotation;
-using Content.Shared.Standing;
-using JetBrains.Annotations;
-using Robust.Server.GameObjects;
-using Robust.Shared.Audio;
-using Robust.Shared.GameObjects;
-using Robust.Shared.Player;
-
-namespace Content.Server.Standing
-{
-    [UsedImplicitly]
-    public class StandingStateSystem : SharedStandingStateSystem
-    {
-        protected override bool OnDown(IEntity entity, bool playSound = true, bool dropItems = true, bool force = false)
-        {
-            if (!entity.TryGetComponent(out AppearanceComponent? appearance))
-            {
-                return false;
-            }
-
-            var newState = RotationState.Horizontal;
-            appearance.TryGetData<RotationState>(RotationVisuals.RotationState, out var oldState);
-
-            if (newState != oldState)
-            {
-                appearance.SetData(RotationVisuals.RotationState, newState);
-
-                if (playSound)
-                {
-                    var file = AudioHelpers.GetRandomFileFromSoundCollection("bodyfall");
-                    SoundSystem.Play(Filter.Pvs(entity), file, entity, AudioHelpers.WithVariation(0.25f));
-                }
-            }
-
-            return true;
-        }
-
-        protected override bool OnStand(IEntity entity)
-        {
-            if (!entity.TryGetComponent(out AppearanceComponent? appearance)) return false;
-
-            appearance.TryGetData<RotationState>(RotationVisuals.RotationState, out var oldState);
-            var newState = RotationState.Vertical;
-
-            if (newState == oldState) return false;
-
-            appearance.SetData(RotationVisuals.RotationState, newState);
-
-            return true;
-        }
-
-        public override void DropAllItemsInHands(IEntity entity, bool doMobChecks = true)
-        {
-            base.DropAllItemsInHands(entity, doMobChecks);
-
-            if (!entity.TryGetComponent(out IHandsComponent? hands)) return;
-
-            foreach (var heldItem in hands.GetAllHeldItems())
-            {
-                hands.Drop(heldItem.Owner, doMobChecks, intentional:false);
-            }
-        }
-
-        //TODO: RotationState can be null and I want to burn all lifeforms in the universe for this!!!
-        //If you use these it's atleast slightly less painful (null is treated as false)
-        public bool IsStanding(IEntity entity)
-        {
-            return entity.TryGetComponent<AppearanceComponent>(out var appearance)
-                && appearance.TryGetData<RotationState>(RotationVisuals.RotationState, out var rotation)
-                && rotation == RotationState.Vertical;
-        }
-
-        public bool IsDown(IEntity entity)
-        {
-            return entity.TryGetComponent<AppearanceComponent>(out var appearance)
-                && appearance.TryGetData<RotationState>(RotationVisuals.RotationState, out var rotation)
-                && rotation == RotationState.Horizontal;
-        }
-    }
-}

Content.Server/Stunnable/Components/StunnableComponent.cs

@@ -1,11 +1,10 @@
 #nullable enable
 using Content.Server.Act;
 using Content.Server.Notification;
-using Content.Server.Standing;
 using Content.Shared.Audio;
 using Content.Shared.MobState;
-using Content.Shared.Notification;
 using Content.Shared.Notification.Managers;
+using Content.Shared.Standing;
 using Content.Shared.Stunnable;
 using Robust.Shared.Audio;
 using Robust.Shared.GameObjects;
@@ -28,7 +27,7 @@ namespace Content.Server.Stunnable.Components
         protected override void OnKnockdownEnd()
         {
             if(Owner.TryGetComponent(out IMobStateComponent? mobState) && !mobState.IsIncapacitated())
-                EntitySystem.Get<StandingStateSystem>().Standing(Owner);
+                EntitySystem.Get<StandingStateSystem>().Stand(Owner);
         }
 
         public void CancelAll()
@@ -46,7 +45,7 @@ namespace Content.Server.Stunnable.Components
             if (KnockedDown &&
                 Owner.TryGetComponent(out IMobStateComponent? mobState) && !mobState.IsIncapacitated())
             {
-                EntitySystem.Get<StandingStateSystem>().Standing(Owner);
+                EntitySystem.Get<StandingStateSystem>().Stand(Owner);
             }
 
             KnockdownTimer = null;

Content.Shared/Body/Components/SharedBodyComponent.cs

@@ -189,7 +189,7 @@ namespace Content.Shared.Body.Components
             if (part.PartType == BodyPartType.Leg &&
                 GetPartsOfType(BodyPartType.Leg).ToArray().Length == 0)
             {
-                EntitySystem.Get<SharedStandingStateSystem>().Down(Owner);
+                EntitySystem.Get<StandingStateSystem>().Down(Owner);
             }
 
             // creadth: immediately kill entity if last vital part removed

Content.Shared/Buckle/Components/SharedBuckleComponent.cs

@@ -48,10 +48,7 @@ namespace Content.Shared.Buckle.Components
             return !Buckled;
         }
 
-        bool IEffectBlocker.CanFall()
+        bool IEffectBlocker.CanFall() => !Buckled;
-        {
-            return !Buckled;
-        }
 
         bool IDraggable.CanDrop(CanDropEvent args)
         {

Content.Shared/Buckle/SharedBuckleSystem.cs

@@ -1,4 +1,5 @@
 using Content.Shared.Buckle.Components;
+using Content.Shared.Standing;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Physics.Dynamics;
 
@@ -10,6 +11,24 @@ namespace Content.Shared.Buckle
         {
             base.Initialize();
             SubscribeLocalEvent<SharedBuckleComponent, PreventCollideEvent>(PreventCollision);
+            SubscribeLocalEvent<SharedBuckleComponent, DownAttemptEvent>(HandleDown);
+            SubscribeLocalEvent<SharedBuckleComponent, StandAttemptEvent>(HandleStand);
+        }
+
+        private void HandleStand(EntityUid uid, SharedBuckleComponent component, StandAttemptEvent args)
+        {
+            if (component.Buckled)
+            {
+                args.Cancel();
+            }
+        }
+
+        private void HandleDown(EntityUid uid, SharedBuckleComponent component, DownAttemptEvent args)
+        {
+            if (component.Buckled)
+            {
+                args.Cancel();
+            }
         }
 
         private void PreventCollision(EntityUid uid, SharedBuckleComponent component, PreventCollideEvent args)

Content.Shared/EffectBlocker/EffectBlockerSystem.cs

@@ -1,4 +1,5 @@
 #nullable enable
+using System;
 using Content.Shared.ActionBlocker;
 using JetBrains.Annotations;
 using Robust.Shared.GameObjects;

Content.Shared/Hands/SharedHandsSystem.cs

@@ -23,6 +23,38 @@ namespace Content.Shared.Hands
             SubscribeNetworkEvent<RequestDropHeldEntityEvent>(HandleDrop);
         }
 
+        public void DropHandItems(IEntity entity, bool doMobChecks = true)
+        {
+            if (!entity.TryGetComponent(out SharedHandsComponent? handsComponent)) return;
+            DropHandItems(handsComponent, doMobChecks);
+        }
+
+        private void DropHandItems(SharedHandsComponent handsComponent, bool doMobChecks = true)
+        {
+            var msg = new DropHandItemsAttemptEvent();
+            var entity = handsComponent.Owner;
+            var uid = entity.Uid;
+            var eventBus = EntityManager.EventBus;
+
+            eventBus.RaiseLocalEvent(uid, msg);
+
+            if (msg.Cancelled) return;
+
+            if (entity.TryGetContainerMan(out var containerManager))
+            {
+                var parentMsg = new ContainedEntityDropHandItemsAttemptEvent(uid);
+                eventBus.RaiseLocalEvent(containerManager.Owner.Uid, parentMsg);
+
+                if (parentMsg.Cancelled) return;
+            }
+
+            DropAllItemsInHands(entity, doMobChecks);
+        }
+
+        protected virtual void DropAllItemsInHands(IEntity entity, bool doMobChecks = true)
+        {
+        }
+
         private void HandleSetHand(RequestSetHandEvent msg, EntitySessionEventArgs eventArgs)
         {
             var entity = eventArgs.SenderSession?.AttachedEntity;
@@ -46,6 +78,18 @@ namespace Content.Shared.Hands
         protected abstract void HandleContainerModified(EntityUid uid, SharedHandsComponent component, ContainerModifiedMessage args);
     }
 
+    public sealed class ContainedEntityDropHandItemsAttemptEvent : CancellableEntityEventArgs
+    {
+        public EntityUid EntityUid { get; }
+
+        public ContainedEntityDropHandItemsAttemptEvent(EntityUid uid)
+        {
+            EntityUid = uid;
+        }
+    }
+
+    public sealed class DropHandItemsAttemptEvent : CancellableEntityEventArgs {}
+
     [Serializable, NetSerializable]
     public class RequestSetHandEvent : EntityEventArgs
     {

Content.Shared/MobState/State/SharedCriticalMobState.cs

@@ -1,5 +1,6 @@
 #nullable enable
 using Content.Shared.Alert;
+using Content.Shared.Hands;
 using Content.Shared.Standing;
 using Robust.Shared.GameObjects;
 
@@ -20,13 +21,20 @@ namespace Content.Shared.MobState.State
             {
                 status.ShowAlert(AlertType.HumanCrit); // TODO: combine humancrit-0 and humancrit-1 into a gif and display it
             }
+
+            EntitySystem.Get<StandingStateSystem>().Down(entity);
+
+            if (entity.TryGetComponent(out SharedAppearanceComponent? appearance))
+            {
+                appearance.SetData(DamageStateVisuals.State, DamageState.Critical);
+            }
         }
 
         public override void ExitState(IEntity entity)
         {
             base.ExitState(entity);
 
-            EntitySystem.Get<SharedStandingStateSystem>().Standing(entity);
+            EntitySystem.Get<StandingStateSystem>().Stand(entity);
         }
 
         public override bool CanInteract()

Content.Shared/MobState/State/SharedDeadMobState.cs

@@ -1,4 +1,6 @@
-using Robust.Shared.GameObjects;
+using Content.Shared.Hands;
+using Content.Shared.Standing;
+using Robust.Shared.GameObjects;
 
 namespace Content.Shared.MobState.State
 {
@@ -11,6 +13,18 @@ namespace Content.Shared.MobState.State
             base.EnterState(entity);
             var wake = entity.EnsureComponent<CollisionWakeComponent>();
             wake.Enabled = true;
+            var standingState = EntitySystem.Get<StandingStateSystem>();
+            standingState.Down(entity);
+
+            if (standingState.IsDown(entity) && entity.TryGetComponent(out PhysicsComponent? physics))
+            {
+                physics.CanCollide = false;
+            }
+
+            if (entity.TryGetComponent(out SharedAppearanceComponent? appearance))
+            {
+                appearance.SetData(DamageStateVisuals.State, DamageState.Dead);
+            }
         }
 
         public override void ExitState(IEntity entity)
@@ -20,6 +34,14 @@ namespace Content.Shared.MobState.State
             {
                 entity.RemoveComponent<CollisionWakeComponent>();
             }
+
+            var standingState = EntitySystem.Get<StandingStateSystem>();
+            standingState.Stand(entity);
+
+            if (!standingState.IsDown(entity) && entity.TryGetComponent(out PhysicsComponent? physics))
+            {
+                physics.CanCollide = true;
+            }
         }
 
         public override bool CanInteract()

Content.Shared/MobState/State/SharedNormalMobState.cs

@@ -1,4 +1,7 @@
-#nullable enable
+using Content.Shared.Standing;
+using Robust.Shared.GameObjects;
+
+#nullable enable
 
 namespace Content.Shared.MobState.State
 {
@@ -9,6 +12,17 @@ namespace Content.Shared.MobState.State
     {
         protected override DamageState DamageState => DamageState.Alive;
 
+        public override void EnterState(IEntity entity)
+        {
+            base.EnterState(entity);
+            EntitySystem.Get<StandingStateSystem>().Stand(entity);
+
+            if (entity.TryGetComponent(out SharedAppearanceComponent? appearance))
+            {
+                appearance.SetData(DamageStateVisuals.State, DamageState.Alive);
+            }
+        }
+
         public override bool CanInteract()
         {
             return true;

Content.Shared/NetIDs/ContentNetIDs.cs

@@ -100,6 +100,7 @@ namespace Content.Shared.NetIDs
         public const uint LIGHT_REPLACER = 1090;
         public const uint SINGULARITY_DISTORTION = 1091;
         public const uint GRAVITY = 1092;
+        public const uint STANDING_STATE = 1093;
 
         // Net IDs for integration tests.
         public const uint PREDICTION_TEST = 10001;

Content.Shared/Standing/SharedStandingStateSystem.cs

@@ -1,51 +0,0 @@
-#nullable enable
-using Content.Shared.EffectBlocker;
-using Robust.Shared.GameObjects;
-
-namespace Content.Shared.Standing
-{
-    public abstract class SharedStandingStateSystem : EntitySystem
-    {
-        protected abstract bool OnDown(IEntity entity, bool playSound = true, bool dropItems = true,
-            bool force = false);
-
-        protected abstract bool OnStand(IEntity entity);
-
-        /// <summary>
-        ///     Set's the mob standing state to down.
-        /// </summary>
-        /// <param name="entity">The mob in question</param>
-        /// <param name="playSound">Whether to play a sound when falling down or not</param>
-        /// <param name="dropItems">Whether to make the mob drop all the items on his hands</param>
-        /// <param name="force">Whether or not to check if the entity can fall.</param>
-        /// <returns>False if the mob was already downed or couldn't set the state</returns>
-        public bool Down(IEntity entity, bool playSound = true, bool dropItems = true, bool force = false)
-        {
-            if (dropItems)
-            {
-                DropAllItemsInHands(entity, false);
-            }
-
-            if (!force && !EffectBlockerSystem.CanFall(entity))
-            {
-                return false;
-            }
-
-            return OnDown(entity, playSound, dropItems, force);
-        }
-
-        /// <summary>
-        ///     Sets the mob's standing state to standing.
-        /// </summary>
-        /// <param name="entity">The mob in question.</param>
-        /// <returns>False if the mob was already standing or couldn't set the state</returns>
-        public bool Standing(IEntity entity)
-        {
-            return OnStand(entity);
-        }
-
-        public virtual void DropAllItemsInHands(IEntity entity, bool doMobChecks = true)
-        {
-        }
-    }
-}

Content.Shared/Standing/StandingStateComponent.cs

@@ -0,0 +1,54 @@
+using System;
+using Content.Shared.EffectBlocker;
+using Content.Shared.NetIDs;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Players;
+using Robust.Shared.Serialization;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Shared.Standing
+{
+    [RegisterComponent]
+    public sealed class StandingStateComponent : Component, IEffectBlocker
+    {
+        public override string Name => "StandingState";
+
+        public override uint? NetID => ContentNetIDs.STANDING_STATE;
+
+        [ViewVariables(VVAccess.ReadWrite)]
+        [DataField("downSoundCollection")]
+        public string? DownSoundCollection { get; } = "BodyFall";
+
+        [ViewVariables]
+        [DataField("standing")]
+        public bool Standing { get; set; } = true;
+
+        public bool CanFall() => Standing;
+
+        public override ComponentState GetComponentState(ICommonSession player)
+        {
+            return new StandingComponentState(Standing);
+        }
+
+        public override void HandleComponentState(ComponentState? curState, ComponentState? nextState)
+        {
+            base.HandleComponentState(curState, nextState);
+            if (curState is not StandingComponentState state) return;
+
+            Standing = state.Standing;
+        }
+
+        // I'm not calling it StandingStateComponentState
+        [Serializable, NetSerializable]
+        private sealed class StandingComponentState : ComponentState
+        {
+            public bool Standing { get; }
+
+            public StandingComponentState(bool standing) : base(ContentNetIDs.STANDING_STATE)
+            {
+                Standing = standing;
+            }
+        }
+    }
+}

Content.Shared/Standing/StandingStateSystem.cs

@@ -0,0 +1,126 @@
+#nullable enable
+using Content.Shared.Audio;
+using Content.Shared.Hands;
+using Content.Shared.Rotation;
+using Robust.Shared.Audio;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Player;
+
+namespace Content.Shared.Standing
+{
+    public sealed class StandingStateSystem : EntitySystem
+    {
+        public bool IsDown(IEntity entity)
+        {
+            if (entity.TryGetComponent(out StandingStateComponent? standingState) &&
+                standingState.Standing) return true;
+
+            return false;
+        }
+
+        public void Down(IEntity entity, bool playSound = true, bool dropHeldItems = true)
+        {
+            if (!entity.TryGetComponent(out StandingStateComponent? comp)) return;
+            Down(comp, playSound, dropHeldItems);
+        }
+
+        public void Stand(IEntity entity)
+        {
+            if (!entity.TryGetComponent(out StandingStateComponent? comp)) return;
+            Stand(comp);
+        }
+
+        public void Down(StandingStateComponent component, bool playSound = true, bool dropHeldItems = true)
+        {
+            if (!component.Standing) return;
+
+            var entity = component.Owner;
+            var uid = entity.Uid;
+
+            // This is just to avoid most callers doing this manually saving boilerplate
+            // 99% of the time you'll want to drop items but in some scenarios (e.g. buckling) you don't want to.
+            // We do this BEFORE downing because something like buckle may be blocking downing but we want to drop hand items anyway
+            // and ultimately this is just to avoid boilerplate in Down callers + keep their behavior consistent.
+            if (dropHeldItems)
+            {
+                Get<SharedHandsSystem>().DropHandItems(entity, false);
+            }
+
+            var msg = new DownAttemptEvent();
+            EntityManager.EventBus.RaiseLocalEvent(uid, msg);
+
+            if (msg.Cancelled) return;
+
+            component.Standing = false;
+            component.Dirty();
+            EntityManager.EventBus.RaiseLocalEvent(uid, new DownedEvent());
+
+            // Seemed like the best place to put it
+            if (entity.TryGetComponent(out SharedAppearanceComponent? appearance))
+            {
+                appearance.SetData(RotationVisuals.RotationState, RotationState.Horizontal);
+            }
+
+            // Currently shit is only downed by server but when it's predicted we can probably only play this on server / client
+            var sound = component.DownSoundCollection;
+
+            if (playSound && !string.IsNullOrEmpty(sound))
+            {
+                var file = AudioHelpers.GetRandomFileFromSoundCollection(sound);
+                SoundSystem.Play(Filter.Pvs(entity), file, entity, AudioHelpers.WithVariation(0.25f));
+            }
+        }
+
+        public void Stand(StandingStateComponent component)
+        {
+            if (component.Standing) return;
+
+            var entity = component.Owner;
+            var uid = entity.Uid;
+
+            var msg = new StandAttemptEvent();
+            EntityManager.EventBus.RaiseLocalEvent(uid, msg);
+
+            if (msg.Cancelled) return;
+
+            component.Standing = true;
+            component.Dirty();
+            EntityManager.EventBus.RaiseLocalEvent(uid, new StoodEvent());
+
+            if (entity.TryGetComponent(out SharedAppearanceComponent? appearance))
+            {
+                appearance.SetData(RotationVisuals.RotationState, RotationState.Vertical);
+            }
+        }
+    }
+
+    /// <summary>
+    /// Subscribe if you can potentially block a down attempt.
+    /// </summary>
+    public sealed class DownAttemptEvent : CancellableEntityEventArgs
+    {
+
+    }
+
+    /// <summary>
+    /// Subscribe if you can potentially block a stand attempt.
+    /// </summary>
+    public sealed class StandAttemptEvent : CancellableEntityEventArgs
+    {
+
+    }
+
+    /// <summary>
+    /// Raised when an entity becomes standing
+    /// </summary>
+    public sealed class StoodEvent : EntityEventArgs
+    {
+    }
+
+    /// <summary>
+    /// Raised when an entity is not standing
+    /// </summary>
+    public sealed class DownedEvent : EntityEventArgs
+    {
+    }
+}

Resources/Prototypes/Entities/Mobs/Species/human.yml

@@ -237,7 +237,7 @@
   - type: Grammar
     attributes:
       proper: true
-
+  - type: StandingState
 
 - type: entity
   save: false

Resources/Prototypes/SoundCollections/body_fall.yml

@@ -1,5 +1,5 @@
 - type: soundCollection
-  id: bodyfall
+  id: BodyFall
   files:
   - /Audio/Effects/bodyfall1.ogg
   - /Audio/Effects/bodyfall2.ogg