Sync Time-of-Day Switches copy/paste interaction (#462)

I've checked the GitHub page of this specific mod, and noticed copy/paste interaction which did not look synced. I've decided to take a quick look at it and give a try at syncing it. I believe everything should work fine.

Source/Mods/TimeOfDAySwitch.cs

@@ -1,5 +1,6 @@
 using HarmonyLib;
 using Multiplayer.API;
+using RimWorld;
 using Verse;
 
 namespace Multiplayer.Compat
@@ -10,9 +11,44 @@ namespace Multiplayer.Compat
     [MpCompatFor("Merthsoft.TimeOfDaySwitch")]
     class TimeOfDAySwitch
     {
+        // Temporary states. When pasting will temporarily store synced states,
+        // when executing the paste method it will temporarily store current
+        // player's copied state, and restore it after executing.
+        private static bool[] tempState;
+        private static AccessTools.FieldRef<bool[]> copiedStatesField;
+
         public TimeOfDAySwitch(ModContentPack mod)
         {
-            MP.RegisterSyncMethod(AccessTools.Method("Merthsoft.TimerSwitches.TimeOfDaySwitch:SetState"));
+            var type = AccessTools.TypeByName("Merthsoft.TimerSwitches.TimeOfDaySwitch");
+            MP.RegisterSyncMethod(type, "SetState");
+            // Pasting requires us to also sync the copied state which will be pasted,
+            // so we need to transform the target to sync it as well.
+            MP.RegisterSyncMethod(type, "Paste")
+                .SetPreInvoke(PrePaste)
+                .SetPostInvoke(PostPaste)
+                .TransformTarget(Serializer.New(
+                    (Building_PowerSwitch building) => (building, states: copiedStatesField()),
+                    tuple =>
+                    {
+                        tempState = tuple.states;
+                        return tuple.building;
+                    }), true);
+
+            // Field ref for accessing the copied state, we'll need to change those when copy/pasting stuff.
+            copiedStatesField = AccessTools.StaticFieldRefAccess<bool[]>(
+                AccessTools.DeclaredField("Merthsoft.TimerSwitches.ClipBoard:states"));
+        }
+
+        private static void PrePaste(object instance, object[] args)
+        {
+            ref var state = ref copiedStatesField();
+            (state, tempState) = (tempState, state);
+        }
+
+        private static void PostPaste(object instance, object[] args)
+        {
+            copiedStatesField() = tempState;
+            tempState = null;
         }
     }
 }