Don't allow anchorable overlap (#10461)

* Don't allow anchorable overlap

Should significantly reduce incidents of wall pushing.

* woops

Content.Server/Construction/AnchorableSystem.cs

@@ -1,5 +1,4 @@
 using System.Threading;
-using System.Threading.Tasks;
 using Content.Server.Administration.Logs;
 using Content.Server.Coordinates.Helpers;
 using Content.Server.Popups;
@@ -11,6 +10,7 @@ using Content.Shared.Database;
 using Content.Shared.Examine;
 using Content.Shared.Pulling.Components;
 using Content.Shared.Tools.Components;
+using Robust.Shared.Map;
 using Robust.Shared.Player;
 
 namespace Content.Server.Construction
@@ -18,6 +18,7 @@ namespace Content.Server.Construction
     public sealed class AnchorableSystem : SharedAnchorableSystem
     {
         [Dependency] private readonly IAdminLogManager _adminLogger = default!;
+        [Dependency] private readonly IMapManager _mapManager = default!;
         [Dependency] private readonly PopupSystem _popup = default!;
         [Dependency] private readonly ToolSystem _toolSystem = default!;
         [Dependency] private readonly PullingSystem _pullingSystem = default!;
@@ -71,6 +72,12 @@ namespace Content.Server.Construction
         {
             component.CancelToken = null;
             var xform = Transform(uid);
+            if (TryComp<PhysicsComponent>(uid, out var anchorBody) &&
+                !TileFree(xform.Coordinates, anchorBody))
+            {
+                _popup.PopupEntity(Loc.GetString("anchorable-occupied"), uid, Filter.Entities(args.User));
+                return;
+            }
 
             // Snap rotation to cardinal (multiple of 90)
             var rot = xform.LocalRotation;
@@ -81,8 +88,9 @@ namespace Content.Server.Construction
                 _pullingSystem.TryStopPull(pullable);
             }
 
+            // TODO: Anchoring snaps rn anyway!
             if (component.Snap)
-                xform.Coordinates = xform.Coordinates.SnapToGrid();
+                xform.Coordinates = xform.Coordinates.SnapToGrid(EntityManager, _mapManager);
 
             RaiseLocalEvent(uid, new BeforeAnchoredEvent(args.User, args.Using), false);
             xform.Anchored = true;
@@ -97,6 +105,34 @@ namespace Content.Server.Construction
             );
         }
 
+        private bool TileFree(EntityCoordinates coordinates, PhysicsComponent anchorBody)
+        {
+            // Probably ignore CanCollide on the anchoring body?
+            var gridUid = coordinates.GetGridUid(EntityManager);
+
+            if (!_mapManager.TryGetGrid(gridUid, out var grid))
+                return false;
+
+            var tileIndices = grid.TileIndicesFor(coordinates);
+            var enumerator = grid.GetAnchoredEntitiesEnumerator(tileIndices);
+            var bodyQuery = GetEntityQuery<PhysicsComponent>();
+
+            while (enumerator.MoveNext(out var ent))
+            {
+                if (!bodyQuery.TryGetComponent(ent, out var body) ||
+                    !body.CanCollide)
+                    continue;
+
+                if ((body.CollisionMask & anchorBody.CollisionLayer) != 0x0 ||
+                    (body.CollisionLayer & anchorBody.CollisionMask) != 0x0)
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
         /// <summary>
         ///     Checks if a tool can change the anchored status.
         /// </summary>
@@ -135,14 +171,24 @@ namespace Content.Server.Construction
             SharedPullableComponent? pullable = null,
             ToolComponent? usingTool = null)
         {
-            if (!Resolve(uid, ref anchorable, ref transform)) return;
+            if (!Resolve(uid, ref anchorable, ref transform))
+                return;
 
             // Optional resolves.
             Resolve(uid, ref pullable, false);
 
-            if (!Resolve(usingUid, ref usingTool)) return;
+            if (!Resolve(usingUid, ref usingTool))
+                return;
 
-            if (!Valid(uid, userUid, usingUid, true, anchorable, usingTool)) return;
+            if (!Valid(uid, userUid, usingUid, true, anchorable, usingTool))
+                return;
+
+            if (TryComp<PhysicsComponent>(uid, out var anchorBody) &&
+                !TileFree(transform.Coordinates, anchorBody))
+            {
+                _popup.PopupEntity(Loc.GetString("anchorable-occupied"), uid, Filter.Entities(userUid));
+                return;
+            }
 
             anchorable.CancelToken = new CancellationTokenSource();
 

Content.Shared/Construction/EntitySystems/SharedAnchorableSystem.cs

@@ -1,4 +1,3 @@
-using System.Threading.Tasks;
 using Content.Shared.Construction.Components;
 using Content.Shared.Containers.ItemSlots;
 using Content.Shared.Interaction;

Resources/Locale/en-US/anchorable/anchorable-component.ftl

@@ -1,2 +1,3 @@
 anchorable-anchored = Anchored
-anchorable-unanchored = Unanchored
+anchorable-unanchored = Unanchored
+anchorable-occupied = Tile occupied