fix drop boss bag hook not working properly

OTAPI.Patcher/Targets/PCServerTarget.cs

@@ -210,6 +210,7 @@ public void Patch()
                             mm.Module.GetType("Terraria.NPC").CreateHooks(mm);
                             mm.Module.GetType("Terraria.WorldGen").CreateHooks(mm);
                             mm.Module.GetType("Terraria.Chat.ChatHelper").CreateHooks(mm);
+                            mm.Module.GetType("Terraria.GameContent.ItemDropRules.CommonCode").CreateHooks(mm);
                             mm.Module.GetType("Terraria.IO.WorldFile").CreateHooks(mm);
                             mm.Module.GetType("Terraria.Net.NetManager").CreateHooks(mm);
                             mm.Module.GetType("Terraria.Projectile").CreateHooks(mm);

OTAPI.Scripts/Patches/PatchNpcBossBag.Server.cs

@@ -0,0 +1,112 @@
+/*
+Copyright (C) 2020 DeathCradle
+
+This file is part of Open Terraria API v3 (OTAPI)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+#pragma warning disable CS8321 // Local function is declared but never used
+#pragma warning disable CS0436 // Type conflicts with imported type
+
+using System;
+using ModFramework;
+using MonoMod.Cil;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+using System.Linq;
+using MonoMod;
+
+/// <summary>
+/// @doc Creates Hooks.NPC.BossBag. Allows plugins to customize bosses loot as well as distributing it.
+/// </summary>
+
+[MonoModIgnore]
+partial class NpcBossBag
+{
+    [Modification(ModType.PreMerge, "Hooking NPC Boss Bag")]
+    static void HookNpcBossBag(ModFwModder modder)
+    {
+        foreach (var csr in new[] {
+            modder.GetILCursor(() => (new Terraria.NPC()).DropItemInstanced(default, default, 0, 0, false)),
+            modder.GetILCursor(() => Terraria.GameContent.ItemDropRules.CommonCode.DropItemLocalPerClientAndSetNPCMoneyTo0(default, default, default, default))
+        })
+        {
+            csr.GotoNext(MoveType.After,
+                i => i.OpCode == OpCodes.Ldsfld &&
+                     i.Operand is FieldReference fieldReference &&
+                     fieldReference.Name == "netMode" &&
+                     fieldReference.DeclaringType.FullName == "Terraria.Main",
+                i => i.OpCode == OpCodes.Ldc_I4_2,
+                i => i.OpCode == OpCodes.Bne_Un
+            );
+
+            csr.Emit(OpCodes.Ldarg_0);
+            if (csr.Method.Name == "DropItemLocalPerClientAndSetNPCMoneyTo0")
+            {
+                csr.Emit(OpCodes.Ldarg_1);
+                csr.Emit(OpCodes.Ldarg_2);
+                csr.Emit(OpCodes.Ldarg_3);
+            }
+            else
+            {
+                csr.Emit(OpCodes.Ldarg_3);
+                csr.Emit(OpCodes.Ldarg, 4);
+                csr.Emit(OpCodes.Ldarg, 5);
+            }
+            csr.EmitDelegate(OTAPI.Hooks.NPC.InvokeBossBag);
+            csr.Emit(OpCodes.Nop);
+            csr.Emit(OpCodes.Nop);
+
+            csr.Previous.Previous.OpCode = OpCodes.Brtrue;
+            csr.Previous.Previous.Operand = csr.Next;
+
+            var targetBranch = csr.Method.Body.Instructions.Reverse().Where(x => x.OpCode == OpCodes.Ldarg_0).FirstOrDefault();
+
+            csr.Previous.OpCode = OpCodes.Br;
+            csr.Previous.Operand = targetBranch;
+        }
+    }
+}
+
+namespace OTAPI
+{
+    public static partial class Hooks
+    {
+        public static partial class NPC
+        {
+            public class BossBagEventArgs : EventArgs
+            {
+                public HookResult? Result { get; set; }
+                public Terraria.NPC NPC { get; set; }
+                public int ItemID { get; set; }
+                public int Stack { get; set; }
+                public bool InteractionRequired { get; set; }
+            }
+            public static event EventHandler<BossBagEventArgs> BossBag;
+
+            public static bool InvokeBossBag(Terraria.NPC npc, int itemid, int stack, bool interactionRequired)
+            {
+                var args = new BossBagEventArgs()
+                {
+                    NPC = npc,
+                    ItemID = itemid,
+                    Stack = stack,
+                    InteractionRequired = interactionRequired
+                };
+                BossBag?.Invoke(null, args);
+                return args.Result != HookResult.Cancel;
+            }
+        }
+    }
+}

OTAPI.Scripts/Patches/PatchNpcStrikeArgs.Server.cs

@@ -15,27 +15,27 @@ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 
 You should have received a copy of the GNU General Public License
 along with this program. If not, see <http://www.gnu.org/licenses/>.
-*/
+*/
 #if !tModLoaderServer_V1_3
 using ModFramework;
-using Mono.Cecil;
-using Mono.Cecil.Cil;
-using MonoMod;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+using MonoMod;
 using System;
-using System.Linq;
-
-/// <summary>
-/// @doc Adds a Terraria.Entity entity parameter to Terraria.NPC.StrikeNPC.
-/// </summary>
-[MonoModIgnore]
-partial class NpcStrikeArgs
-{
-    //static ParameterDefinition Entity { get; set; }
-    //static MethodDefinition StrikeNPC { get; set; }
-
-    [Modification(ModType.PreMerge, "Patching in entity source for NPC strike")]
-    static void PatchNpcStrikeArgs(ModFwModder modder)
-    {
+using System.Linq;
+
+/// <summary>
+/// @doc Adds a Terraria.Entity entity parameter to Terraria.NPC.StrikeNPC.
+/// </summary>
+[MonoModIgnore]
+partial class NpcStrikeArgs
+{
+    //static ParameterDefinition Entity { get; set; }
+    //static MethodDefinition StrikeNPC { get; set; }
+
+    [Modification(ModType.PreMerge, "Patching in entity source for NPC strike")]
+    static void PatchNpcStrikeArgs(ModFwModder modder)
+    {
         var csr = modder.GetILCursor(() => (new Terraria.NPC()).StrikeNPC(0, 0, 0, false, false, false));
         var redirects = csr.Method.DeclaringType.Methods
             .Where(x => (HookEmitter.HookMethodNamePrefix + x.Name) == csr.Method.Name || ("orig_" + x.Name) == csr.Method.Name)
@@ -45,16 +45,16 @@ static void PatchNpcStrikeArgs(ModFwModder modder)
         foreach (var method in redirects.Append(csr))
         {
             ParameterDefinition Entity;
-            method.Method.Parameters.Add(Entity = new ("entity",
-                ParameterAttributes.HasDefault | ParameterAttributes.Optional,
-
-                modder.Module.ImportReference(modder.GetDefinition<Terraria.Entity>())
+            method.Method.Parameters.Add(Entity = new ("entity",
+                ParameterAttributes.HasDefault | ParameterAttributes.Optional,
+
+                modder.Module.ImportReference(modder.GetDefinition<Terraria.Entity>())
             )
             {
                 Constant = null
             });
 
-            modder.OnRewritingMethodBody += (MonoModder modder, MethodBody body, Instruction instr, int instri) =>
+            modder.OnRewritingMethodBody += (MonoModder modder, MethodBody body, Instruction instr, int instri) =>
             {
                 if (instr.Operand is MethodReference methodReference)
                 {
@@ -102,7 +102,7 @@ static void PatchNpcStrikeArgs(ModFwModder modder)
                     }
                 }
             };
-        }
-    }
+        }
+    }
 }
 #endif