Alpha Prefabs compat (#407)

Source/Mods/AlphaPrefabs.cs

@@ -0,0 +1,151 @@
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Reflection.Emit;
+using HarmonyLib;
+using Multiplayer.API;
+using RimWorld;
+using Verse;
+
+namespace Multiplayer.Compat
+{
+    /// <summary>
+    /// Alpha Prefabs by Sarg Bjornson
+    /// </summary>
+    /// <see href="https://steamcommunity.com/sharedfiles/filedetails/?id=3070780021"/>
+    /// <see href="https://github.com/juanosarg/AlphaPrefabs"/>
+    [MpCompatFor("Sarg.AlphaPrefabs")]
+    public class AlphaPrefabs
+    {
+        #region Fields
+
+        // Window_Prefab
+        private static Type windowPrefabType;
+        private static AccessTools.FieldRef<Window, Def> windowPrefabDefField;
+        private static AccessTools.FieldRef<Window, Building> windowPrefabCatalogField;
+        private static FastInvokeHandler checkModsSilverAndResearchMethod;
+
+        #endregion
+
+        #region Main Patch
+
+        public AlphaPrefabs(ModContentPack mod)
+        {
+            MpCompatPatchLoader.LoadPatch(this);
+
+            // Gizmos
+            // Build (0), undeploy (1)
+            MpCompat.RegisterLambdaMethod("AlphaPrefabs.Building_DeployedPrefab", nameof(Building.GetGizmos), 0, 1);
+
+            // Float menu
+            MpCompat.RegisterLambdaDelegate("AlphaPrefabs.CompTargetable_Ground", nameof(CompTargetable.SelectedUseOption), 0);
+
+            // Dialogs
+            var type = windowPrefabType = AccessTools.TypeByName("AlphaPrefabs.Window_Prefab");
+            windowPrefabDefField = AccessTools.FieldRefAccess<Def>(type, "prefab");
+            windowPrefabCatalogField = AccessTools.FieldRefAccess<Building>(type, "building");
+            checkModsSilverAndResearchMethod = MethodInvoker.GetHandler(AccessTools.DeclaredMethod(type, "CheckModsSilverAndResearch"));
+            MP.RegisterSyncMethod(type, "OrderPrefab")
+                .SetContext(SyncContext.CurrentMap);
+        }
+
+        #endregion
+
+        #region Immediate Feedback
+
+        [MpCompatPrefix("AlphaPrefabs.Window_Prefab", "OrderPrefab")]
+        private static bool PreOrderPrefab(Window __instance)
+        {
+            // Not in MP, let it run as normal
+            if (!MP.IsInMultiplayer)
+                return true;
+
+            var args = new object[1];
+            if ((bool)checkModsSilverAndResearchMethod(__instance, args))
+            {
+                // By returning true MP will catch the method call and sync it.
+                // However, we close the dialog as well because otherwise it
+                // won't get closed for the player as we construct a new dialog
+                // in the sync worker. We could access this one... But let's just
+                // give the player immediate feedback.
+                __instance.Close();
+                return true;
+            }
+
+            var reason = (string)args[0];
+            var catalog = windowPrefabCatalogField(__instance);
+            // We need to cast null to LookTargets, else it'll treat it as Thing
+            // and implicitly convert it LookTargets with null Thing as the argument.
+            // It shouldn't cause issues... But let's just copy what the mod does.
+            Messages.Message(reason, catalog != null ? catalog : (LookTargets)null, MessageTypeDefOf.RejectInput, false);
+            return false;
+        }
+
+        #endregion
+
+        #region No camera position
+
+        // Basically, the method OrderPrefab will use the player camera's position when sending them
+        // the prefab after purchasing (or the position of catalog building, if using it instead).
+        // We need to patch the method to use a deterministic approach (TradeDropSpot).
+
+        private static IntVec3 ReplaceDropPosition(CameraDriver instance)
+        {
+            if (!MP.IsInMultiplayer)
+                return instance.MapPosition;
+
+            // We need SyncContext.CurrentMap for our replacement and the method itself.
+            return DropCellFinder.TradeDropSpot(Find.CurrentMap);
+        }
+
+        [MpCompatTranspiler("AlphaPrefabs.Window_Prefab", "OrderPrefab")]
+        private static IEnumerable<CodeInstruction> ReplaceCameraMapPosition(IEnumerable<CodeInstruction> instr, MethodBase baseMethod)
+        {
+            var target = AccessTools.PropertyGetter(typeof(CameraDriver), nameof(CameraDriver.MapPosition));
+            var replacement = AccessTools.DeclaredMethod(typeof(AlphaPrefabs), nameof(ReplaceDropPosition));
+            var replacedCount = 0;
+
+            foreach (var ci in instr)
+            {
+                if (ci.Calls(target))
+                {
+                    ci.opcode = OpCodes.Call;
+                    ci.operand = replacement;
+
+                    replacedCount++;
+                }
+
+                yield return ci;
+            }
+
+            const int expected = 1;
+            if (replacedCount != expected)
+            {
+                var name = (baseMethod.DeclaringType?.Namespace).NullOrEmpty() ? baseMethod.Name : $"{baseMethod.DeclaringType!.Name}:{baseMethod.Name}";
+                Log.Warning($"Patched incorrect number of Find.CameraDriver.MapPosition calls (patched {replacedCount}, expected {expected}) for method {name}");
+            }
+        }
+
+        #endregion
+
+        #region Sync Workers
+
+        [MpCompatSyncWorker("AlphaPrefabs.Window_Prefab")]
+        public static void SyncWindowPrefab(SyncWorker sync, ref Window dialog)
+        {
+            if (sync.isWriting)
+            {
+                sync.Write(windowPrefabDefField(dialog));
+                sync.Write(windowPrefabCatalogField(dialog));
+            }
+            else
+            {
+                var prefabDef = sync.Read<Def>();
+                var catalog = sync.Read<Building>();
+                dialog ??= (Window)Activator.CreateInstance(windowPrefabType, prefabDef, catalog);
+            }
+        }
+
+        #endregion
+    }
+}