Puddles & spreader refactor (#15191)

Content.Server/Spreader/SpreaderNodeGroup.cs

@@ -0,0 +1,31 @@
+using Content.Server.NodeContainer.NodeGroups;
+using Content.Server.NodeContainer.Nodes;
+
+namespace Content.Server.Spreader;
+
+[NodeGroup(NodeGroupID.Spreader)]
+public sealed class SpreaderNodeGroup : BaseNodeGroup
+{
+    private IEntityManager _entManager = default!;
+
+    /// <inheritdoc/>
+    public override void Initialize(Node sourceNode, IEntityManager entMan)
+    {
+        base.Initialize(sourceNode, entMan);
+        _entManager = entMan;
+    }
+
+    /// <inheritdoc/>
+    public override void RemoveNode(Node node)
+    {
+        base.RemoveNode(node);
+
+        foreach (var neighborNode in node.ReachableNodes)
+        {
+            if (_entManager.Deleted(neighborNode.Owner))
+                continue;
+
+            _entManager.EnsureComponent<EdgeSpreaderComponent>(neighborNode.Owner);
+        }
+    }
+}