ported from perforce

RobotAndDonkey.Game/Utils/DirectionExtensions.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace RobotAndDonkey.Game.Utils;
+
+
+public static class DirectionExtensions
+{
+    public static EDirection Opposite(this EDirection d) => Modify(d, 3);
+    public static EDirection RotateLeft(this EDirection d) => Modify(d, 1);
+    public static EDirection RotateRight(this EDirection d) => Modify(d, 5);
+
+    public static EDirection Modify(EDirection direction, int delta)
+    {
+        var i = (int)direction;
+        i += delta;
+        i %= 6;
+        if (i < 0)
+            i += 6;
+        return (EDirection)i;
+    }
+}