// Reference: 0Harmony

using HarmonyLib;
using System.Collections.Generic;
using System.Reflection.Emit;
using System.Reflection;
using UnityEngine;
using System.Linq;
using Facepunch;

namespace Oxide.Plugins
{
    [Info("No Incen AHeli", "ViolationHandler", "0.0.3")]
    [Description("Prevents usage of incen rockets in the Attack Helicopters.")]
    public class NoIncenAHeli : RustPlugin
    {
        private Harmony _harmonyInstance;
        
        private void Loaded()
        {
            _harmonyInstance = new Harmony("com.ViolationHandler" + Name);
            _harmonyInstance.Patch(AccessTools.Method(typeof(AttackHelicopterRockets), nameof(AttackHelicopterRockets.ItemFilter)), transpiler: new HarmonyMethod(typeof(NoIncenAttackHeli), nameof(NoIncenAttackHeli.Transpiler)));
        }
        private void Unload()
        {
            _harmonyInstance?.UnpatchAll(_harmonyInstance.Id);
        }

        public class NoIncenAttackHeli
        {
            internal static IEnumerable<CodeInstruction> Transpiler(IEnumerable<CodeInstruction> instructions, ILGenerator ilGenerator)
            {
                List<CodeInstruction> list = instructions.ToList();
                Label skip = ilGenerator.DefineLabel();
                if (list[0].labels == null) list[0].labels = new List<Label> { skip };
                else list[0].labels.Add(skip);
                list.InsertRange(0, new List<CodeInstruction>
                {
                    // load Item
                    new CodeInstruction(OpCodes.Ldarg_1), 
                    // Get ItemDefinition
                    new CodeInstruction(OpCodes.Ldfld, AccessTools.Field(typeof(Item), nameof(global::Item.info))), 
                    // Load This
                    new CodeInstruction(OpCodes.Ldarg_0), 
                    // Load Incendiary Rocket ItemDefinition
                    new CodeInstruction(OpCodes.Ldfld, AccessTools.Field(typeof(AttackHelicopterRockets), "incendiaryRocketDef")), 
                    // Check if equal to the item definition from arg_1
                    new CodeInstruction(OpCodes.Call, AccessTools.Method(typeof(UnityEngine.Object), nameof(UnityEngine.Object.Equals))),
                    // If not equal, then go to the next portion of checks in default code.
                    new CodeInstruction(OpCodes.Brfalse, skip),
                    // If equal, then return false and don't allow it.
                    new CodeInstruction(OpCodes.Ldc_I4_0),
                    new CodeInstruction(OpCodes.Ret)
                });
                return list;
            }
            
        }
    }
}