Fix ColorSubgraph()

PamhagenSysCtrl/Helpers/PamhagenGraph.cs

@@ -1,4 +1,5 @@
 using PamhagenSysCtrl.Helpers.Pipeline;
+using System.Windows.Media;
 
 namespace PamhagenSysCtrl.Helpers {
     public class PamhagenGraph : Graph {
@@ -337,5 +338,26 @@ namespace PamhagenSysCtrl.Helpers {
         protected static Tank CreateTank(int n, double x, double y, int capacity) {
             return new($"Tank {n}", x, y, capacity, () => App.Plant?.TankFillLevels[n - 1] != FillState.Empty, () => App.Plant?.TankFillLevels[n - 1] != FillState.Full);
         }
+
+        public void ColorSubgraph(INode start, Brush color, Action<Valve>? valveAction = null) {
+            if (start is Valve v) {
+                valveAction?.Invoke(v);
+                return;
+            } else if (start is ISink || start is Pump) {
+                return;
+            }
+            foreach (var edge in start.Inputs) {
+                if (edge.Highlight != null) continue;
+                var o = edge.IsTwoWay && edge.Start == start ? edge.End : edge.Start;
+                edge.Highlight = color;
+                ColorSubgraph(o, color, valveAction);
+            }
+            foreach (var edge in start.Outputs) {
+                if (edge.Highlight != null) continue;
+                var o = edge.IsTwoWay && edge.End == start ? edge.Start : edge.End;
+                edge.Highlight = color;
+                ColorSubgraph(o, color, valveAction);
+            }
+        }
     }
 }