using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Reflection.Emit;
using HarmonyLib;
using NitroxModel.Helper;

namespace NitroxPatcher.Patches.Dynamic;

public sealed partial class CyclopsShieldButton_OnClick_Patch : NitroxPatch, IDynamicPatch
{
    public static readonly MethodInfo TARGET_METHOD = Reflect.Method((CyclopsShieldButton t) => t.OnClick());
    public static readonly OpCode START_CUT_CODE = OpCodes.Ldsfld;
    public static readonly OpCode START_CUT_CODE_CALL = OpCodes.Callvirt;
    public static readonly FieldInfo PLAYER_MAIN_FIELD = Reflect.Field(() => Player.main);
    public static readonly OpCode END_CUT_CODE = OpCodes.Ret;

    public static IEnumerable<CodeInstruction> Transpiler(MethodBase original, IEnumerable<CodeInstruction> instructions)
    {
        List<CodeInstruction> instructionList = instructions.ToList();
        int startCut = 0;
        int endCut = instructionList.Count;
        /* Cut out
         * if (Player.main.currentSub != this.subRoot)
         * {
         * 	return;
         * }
         */
        for (int i = 1; i < instructionList.Count; i++)
        {
            if (instructionList[i - 1].opcode.Equals(START_CUT_CODE) && instructionList[i - 1].operand.Equals(PLAYER_MAIN_FIELD) && instructionList[i].opcode == START_CUT_CODE_CALL)
            {
                startCut = i - 1;
            }
            // Cut at the first return encountered
            if (endCut == instructionList.Count && instructionList[i].opcode.Equals(END_CUT_CODE))
            {
                endCut = i;
            }
        }
        instructionList.RemoveRange(startCut, endCut + 1);
        if (startCut == 0)
        {
            instructionList.Insert(0, new CodeInstruction(OpCodes.Nop));
        }
        return instructionList;
    }
}