using System;
using System.Collections.Generic;
using UnityEngine;

namespace Kill.Utils
{
    /// <summary>
    /// 主线程执行器 - 确保回调在主线程执行
    /// </summary>
    public class MainThread : MonoBehaviour
    {
        private static MainThread _instance;
        private static readonly Queue<Action> _actions = new Queue<Action>();
        private static readonly object _lock = new object();

        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
        private static void Initialize()
        {
            var go = new GameObject("MainThread");
            _instance = go.AddComponent<MainThread>();
            DontDestroyOnLoad(go);
        }

        private void Update()
        {
            lock (_lock)
            {
                while (_actions.Count > 0)
                {
                    _actions.Dequeue()?.Invoke();
                }
            }
        }

        /// <summary>
        /// 在主线程执行
        /// </summary>
        public static void Enqueue(Action action)
        {
            if (action == null) return;

            // 如果已经在主线程，直接执行
            if (_instance != null && _instance.gameObject != null)
            {
                lock (_lock)
                {
                    _actions.Enqueue(action);
                }
            }
            else
            {
                // 如果调度器还没初始化，延迟执行
                Debug.LogWarning("MainThread 未初始化，尝试延迟执行");
                action?.Invoke();
            }
        }

        /// <summary>
        /// 立即在主线程执行（如果已经在主线程）或排队
        /// </summary>
        public static void Run(Action action)
        {
            if (action == null) return;

            // 检查是否在主线程
            if (Time.frameCount > 0)
            {
                // 已经在主线程，直接执行
                action();
            }
            else
            {
                // 不在主线程，排队
                Enqueue(action);
            }
        }
    }
}