using HarmonyLib;
using System.Collections.Generic;
using System.Reflection.Emit;

namespace Oxide.Plugins;

[Info("Server Projectile Hit Fix", "nivex", "1.0.2")]
[Description("Fix to set initiator for fire entities.")]
public class ServerProjectileHitFix : RustPlugin
{
    private Harmony _harmony;

    private void Loaded()
    {
        _harmony = new Harmony(Name + "Patch");
        _harmony.PatchAll();
    }

    private void Unload()
    {
        _harmony?.UnpatchAll(Name + "Patch");
    }

    [HarmonyPatch(typeof(ItemModProjectileSpawn), "ServerProjectileHit", typeof(HitInfo))]
    internal class ItemModProjectileSpawn_ServerProjectileHit
    {
        [HarmonyTranspiler]
        private static IEnumerable<CodeInstruction> Transpiler(IEnumerable<CodeInstruction> instructions)
        {
            List<CodeInstruction> codes = new(instructions);
            List<CodeInstruction> patch = new()
                {
                    new(OpCodes.Ldarg_1),
                    new(OpCodes.Ldfld, AccessTools.Field(typeof(HitInfo), "Initiator")),
                    new(OpCodes.Stfld, AccessTools.Field(typeof(BaseEntity), "creatorEntity")),
                };
            for (int i = 0; i < codes.Count; i++)
            {
                if (i - 1 >= 0 && codes[i - 1].ToString() == "callvirt Void set_rotation(UnityEngine.Quaternion)")
                {
                    CodeInstruction copy = new(OpCodes.Ldloc_S, codes[i].operand);
                    codes.InsertRange(i, patch);
                    codes.Insert(i, copy);
                }
            }
            return codes;
        }
    }
}