Fluid spread refactor (#11908)

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

Content.Shared/Fluids/SharedPuddleDebugOverlaySystem.cs

@@ -0,0 +1,50 @@
+using Content.Shared.FixedPoint;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.Fluids;
+
+public abstract class SharedPuddleDebugOverlaySystem : EntitySystem
+{
+    protected const float LocalViewRange = 16;
+    protected TimeSpan? NextTick = null;
+    protected TimeSpan Cooldown = TimeSpan.FromSeconds(0.5f);
+}
+
+/// <summary>
+/// Message for disable puddle overlay
+/// </summary>
+[Serializable, NetSerializable]
+public sealed class PuddleOverlayDisableMessage : EntityEventArgs
+{
+}
+
+/// <summary>
+/// Message for puddle overlay display data
+/// </summary>
+[Serializable, NetSerializable]
+public sealed class PuddleOverlayDebugMessage : EntityEventArgs
+{
+    public PuddleDebugOverlayData[] OverlayData { get; }
+
+    public EntityUid GridUid { get; }
+
+
+    public PuddleOverlayDebugMessage(EntityUid gridUid, PuddleDebugOverlayData[] overlayData)
+    {
+        GridUid = gridUid;
+        OverlayData = overlayData;
+    }
+}
+
+[Serializable, NetSerializable]
+public readonly struct PuddleDebugOverlayData
+{
+    public readonly Vector2i Pos;
+    public readonly FixedPoint2 CurrentVolume;
+
+    public PuddleDebugOverlayData(Vector2i pos, FixedPoint2 currentVolume)
+    {
+        CurrentVolume = currentVolume;
+        Pos = pos;
+    }
+}