Fix foldable-pickup interactions. (#6057)

Content.Shared/Foldable/SharedFoldableSystem.cs

@@ -0,0 +1,62 @@
+using Content.Shared.Item;
+using JetBrains.Annotations;
+using Robust.Shared.GameObjects;
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Foldable;
+
+[UsedImplicitly]
+public abstract class SharedFoldableSystem : EntitySystem
+{
+    private const string FoldKey = "FoldedState";
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<FoldableComponent, ComponentGetState>(OnGetState);
+        SubscribeLocalEvent<FoldableComponent, ComponentHandleState>(OnHandleState);
+
+        SubscribeLocalEvent<FoldableComponent, ComponentInit>(OnFoldableInit);
+        SubscribeLocalEvent<FoldableComponent, AttemptItemPickupEvent>(OnPickedUpAttempt);
+    }
+
+    private void OnGetState(EntityUid uid, FoldableComponent component, ref ComponentGetState args)
+    {
+        args.State = new FoldableComponentState(component.IsFolded);
+    }
+
+    private void OnHandleState(EntityUid uid, FoldableComponent component, ref ComponentHandleState args)
+    {
+        if (args.Current is not FoldableComponentState state)
+            return;
+
+        if (state.IsFolded != component.IsFolded)
+            SetFolded(component, state.IsFolded);
+    }
+
+    private void OnFoldableInit(EntityUid uid, FoldableComponent component, ComponentInit args)
+    {
+        SetFolded(component, component.IsFolded);
+    }
+
+    /// <summary>
+    /// Set the folded state of the given <see cref="FoldableComponent"/>
+    /// </summary>
+    /// <param name="component"></param>
+    /// <param name="folded">If true, the component will become folded, else unfolded</param>
+    public virtual void SetFolded(FoldableComponent component, bool folded)
+    {
+        component.IsFolded = folded;
+        component.Dirty();
+
+        if (TryComp(component.Owner, out AppearanceComponent? appearance))
+            appearance.SetData(FoldKey, folded);
+    }
+
+    private void OnPickedUpAttempt(EntityUid uid, FoldableComponent component, AttemptItemPickupEvent args)
+    {
+        if (!component.IsFolded)
+            args.Cancel();
+    }
+}