Remove IInteractUsing (#9718)

Content.Shared/Interaction/InteractUsing.cs

@@ -0,0 +1,46 @@
+using JetBrains.Annotations;
+using Robust.Shared.Map;
+using Robust.Shared.Utility;
+
+namespace Content.Shared.Interaction
+{
+    /// <summary>
+    ///     Raised when a target entity is interacted with by a user while holding an object in their hand.
+    /// </summary>
+    [PublicAPI]
+    public sealed class InteractUsingEvent : HandledEntityEventArgs
+    {
+        /// <summary>
+        ///     Entity that triggered the interaction.
+        /// </summary>
+        public EntityUid User { get; }
+
+        /// <summary>
+        ///     Entity that the user used to interact.
+        /// </summary>
+        public EntityUid Used { get; }
+
+        /// <summary>
+        ///     Entity that was interacted on.
+        /// </summary>
+        public EntityUid Target { get; }
+
+        /// <summary>
+        ///     The original location that was clicked by the user.
+        /// </summary>
+        public EntityCoordinates ClickLocation { get; }
+
+        public InteractUsingEvent(EntityUid user, EntityUid used, EntityUid target, EntityCoordinates clickLocation)
+        {
+            // Interact using should not have the same used and target.
+            // That should be a use-in-hand event instead.
+            // If this is not the case, can lead to bugs (e.g., attempting to merge a item stack into itself).
+            DebugTools.Assert(used != target);
+
+            User = user;
+            Used = used;
+            Target = target;
+            ClickLocation = clickLocation;
+        }
+    }
+}