Retractable items system + Arm Blade action (#38150)

Content.Shared/RetractableItemAction/RetractableItemActionSystem.cs

@@ -0,0 +1,105 @@
+using Content.Shared.Actions;
+using Content.Shared.Hands.EntitySystems;
+using Content.Shared.Interaction.Components;
+using Content.Shared.Popups;
+using Robust.Shared.Audio.Systems;
+using Robust.Shared.Containers;
+
+namespace Content.Shared.RetractableItemAction;
+
+/// <summary>
+/// System for handling retractable items, such as armblades.
+/// </summary>
+public sealed class RetractableItemActionSystem : EntitySystem
+{
+    [Dependency] private readonly SharedHandsSystem _hands = default!;
+    [Dependency] private readonly SharedContainerSystem _containers = default!;
+    [Dependency] private readonly SharedAudioSystem _audio = default!;
+    [Dependency] private readonly SharedActionsSystem _actions = default!;
+    [Dependency] private readonly SharedPopupSystem _popups = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<RetractableItemActionComponent, MapInitEvent>(OnActionInit);
+        SubscribeLocalEvent<RetractableItemActionComponent, OnRetractableItemActionEvent>(OnRetractableItemAction);
+
+        SubscribeLocalEvent<ActionRetractableItemComponent, ComponentShutdown>(OnActionSummonedShutdown);
+    }
+
+    private void OnActionInit(Entity<RetractableItemActionComponent> ent, ref MapInitEvent args)
+    {
+        _containers.EnsureContainer<Container>(ent, RetractableItemActionComponent.ContainerId);
+
+        PopulateActionItem(ent.Owner);
+    }
+
+    private void OnRetractableItemAction(Entity<RetractableItemActionComponent> ent, ref OnRetractableItemActionEvent args)
+    {
+        if (_hands.GetActiveHand(args.Performer) is not { } userHand)
+            return;
+
+        if (_actions.GetAction(ent.Owner) is not { } action)
+            return;
+
+        if (action.Comp.AttachedEntity == null)
+            return;
+
+        if (ent.Comp.ActionItemUid == null)
+            return;
+
+        // Don't allow to summon an item if holding an unremoveable item unless that item is summoned by the action.
+        if (userHand.HeldEntity != null && !_hands.IsHolding(args.Performer, ent.Comp.ActionItemUid) && !_hands.CanDropHeld(args.Performer, userHand, false))
+        {
+            _popups.PopupClient(Loc.GetString("retractable-item-hand-cannot-drop"), args.Performer, args.Performer);
+            return;
+        }
+
+        if (_hands.IsHolding(args.Performer, ent.Comp.ActionItemUid))
+        {
+            RemComp<UnremoveableComponent>(ent.Comp.ActionItemUid.Value);
+            var container = _containers.GetContainer(ent, RetractableItemActionComponent.ContainerId);
+            _containers.Insert(ent.Comp.ActionItemUid.Value, container);
+            _audio.PlayPredicted(ent.Comp.RetractSounds, action.Comp.AttachedEntity.Value, action.Comp.AttachedEntity.Value);
+        }
+        else
+        {
+            _hands.TryForcePickup(args.Performer, ent.Comp.ActionItemUid.Value, userHand, checkActionBlocker: false);
+            _audio.PlayPredicted(ent.Comp.SummonSounds, action.Comp.AttachedEntity.Value, action.Comp.AttachedEntity.Value);
+            EnsureComp<UnremoveableComponent>(ent.Comp.ActionItemUid.Value);
+        }
+
+        args.Handled = true;
+    }
+
+    private void OnActionSummonedShutdown(Entity<ActionRetractableItemComponent> ent, ref ComponentShutdown args)
+    {
+        if (_actions.GetAction(ent.Comp.SummoningAction) is not { } action)
+            return;
+
+        if (!TryComp<RetractableItemActionComponent>(action, out var retract) || retract.ActionItemUid != ent.Owner)
+            return;
+
+        // If the item is somehow destroyed, re-add it to the action.
+        PopulateActionItem(action.Owner);
+    }
+
+    private void PopulateActionItem(Entity<RetractableItemActionComponent?> ent)
+    {
+        if (!Resolve(ent.Owner, ref ent.Comp, false) || TerminatingOrDeleted(ent))
+            return;
+
+        if (!PredictedTrySpawnInContainer(ent.Comp.SpawnedPrototype, ent.Owner, RetractableItemActionComponent.ContainerId, out var summoned))
+            return;
+
+        ent.Comp.ActionItemUid = summoned.Value;
+
+        // Mark the unremovable item so it can be added back into the action.
+        var summonedComp = AddComp<ActionRetractableItemComponent>(summoned.Value);
+        summonedComp.SummoningAction = ent.Owner;
+        Dirty(summoned.Value, summonedComp);
+
+        Dirty(ent);
+    }
+}