Fluid spread refactor (#11908)

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Fix undefined

Content.Client/Fluids/PuddleDebugOverlaySystem.cs

@@ -0,0 +1,45 @@
+using System.Collections;
+using Content.Shared.Fluids;
+using Robust.Client.Graphics;
+
+namespace Content.Client.Fluids;
+
+public sealed class PuddleDebugOverlaySystem : SharedPuddleDebugOverlaySystem
+{
+    [Dependency] private readonly IOverlayManager _overlayManager = default!;
+
+    public readonly Dictionary<EntityUid, PuddleOverlayDebugMessage> TileData = new();
+    private PuddleOverlay? _overlay;
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeNetworkEvent<PuddleOverlayDisableMessage>(DisableOverlay);
+        SubscribeNetworkEvent<PuddleOverlayDebugMessage>(RenderDebugData);
+    }
+
+    private void RenderDebugData(PuddleOverlayDebugMessage message)
+    {
+        TileData[message.GridUid] = message;
+        if (_overlay != null)
+            return;
+
+        _overlay = new PuddleOverlay();
+        _overlayManager.AddOverlay(_overlay);
+    }
+
+    private void DisableOverlay(PuddleOverlayDisableMessage message)
+    {
+        TileData.Clear();
+        if (_overlay == null)
+            return;
+
+        _overlayManager.RemoveOverlay(_overlay);
+        _overlay = null;
+    }
+
+    public PuddleDebugOverlayData[] GetData(EntityUid mapGridGridEntityId)
+    {
+        return TileData[mapGridGridEntityId].OverlayData;
+    }
+}