ninja 2 electric boogaloo (#15534)

Co-authored-by: deltanedas <@deltanedas:kde.org>

Content.Shared/Interaction/InteractHand.cs

@@ -38,6 +38,20 @@ namespace Content.Shared.Interaction
         }
     }
 
+    /// <summary>
+    /// Raised on the user before interacting on an entity with bare hand.
+    /// Interaction is cancelled if this event is handled, so set it to true if you do custom interaction logic.
+    /// </summary>
+    public sealed class BeforeInteractHandEvent : HandledEntityEventArgs
+    {
+        public EntityUid Target { get; }
+
+        public BeforeInteractHandEvent(EntityUid target)
+        {
+            Target = target;
+        }
+    }
+
     /// <summary>
     /// Low-level interaction event used for entities without hands.
     /// </summary>

Content.Shared/Interaction/SharedInteractionSystem.cs

@@ -380,6 +380,15 @@ namespace Content.Shared.Interaction
 
         public void InteractHand(EntityUid user, EntityUid target)
         {
+            // allow for special logic before main interaction
+            var ev = new BeforeInteractHandEvent(target);
+            RaiseLocalEvent(user, ev);
+            if (ev.Handled)
+            {
+                _adminLogger.Add(LogType.InteractHand, LogImpact.Low, $"{ToPrettyString(user):user} interacted with {ToPrettyString(target):target}, but it was handled by another system");
+                return;
+            }
+
             // all interactions should only happen when in range / unobstructed, so no range check is needed
             var message = new InteractHandEvent(user, target);
             RaiseLocalEvent(target, message, true);