using System.Collections;
using System.Collections.Generic;
using Cysharp.Threading.Tasks;
using UnityEngine;

/// <summary>
/// UI帧动画管理器 - 负责帧动画资源的加载和管理
/// </summary>
public class UIFrameMgr {
    private static UIFrameMgr _inst = null;
    private static readonly object _lock = new object();
    
    public static UIFrameMgr Inst {
        get {
            if (_inst == null) {
                lock (_lock) {
                    if (_inst == null) {
                        _inst = new UIFrameMgr();
                    }
                }
            }
            return _inst;
        }
    }

    // 帧动画资源缓存
    private Dictionary<string, List<Sprite>> allFrameDic = new Dictionary<string, List<Sprite>>();
    // 是否已初始化
    private bool isInitialized = false;

    public UIFrameMgr()
    {
        Init();
    }

    /// <summary>
    /// 初始化管理器
    /// </summary>
    public void Init()
    {
        if (isInitialized)
            return;
            
        allFrameDic.Clear();
        isInitialized = true;
    }

    /// <summary>
    /// 加载指定帧动画资源
    /// </summary>
    private void LoadFrameSprites(FrameAnimationConfig cfg)
    {
        if (allFrameDic.ContainsKey(cfg.name))
            return;

        List<UniTask> uniTasks = new List<UniTask>();
            
        List<Sprite> spriteList = new List<Sprite>(new Sprite[cfg.frameCnt]);
        for (int i = 1; i <= cfg.frameCnt; i++)
        {
            int index = i;
            string spritePath = "Sprite/" + cfg.folder;
            string spriteName = StringUtility.Concat(cfg.name, "_", i.ToString());

            var task = ResManager.Instance.LoadAssetAsync<Sprite>(spritePath, spriteName).ContinueWith(sprite =>
            {
                if (sprite != null)
                {
                    spriteList[index - 1] = sprite;
                }
                else
                {
                    Debug.LogError($"加载帧动画资源失败: {spritePath}/{spriteName}");
                }
            });

            uniTasks.Add(task);
        }

        UniTask.WhenAll(uniTasks).ContinueWith(() =>
        {
            if (this == null) // 检查管理器是否已被销毁
                return;
                
            if (spriteList.Count > 0)
            {
                allFrameDic.Add(cfg.name, spriteList);
            }
        }).Forget();
        

    }

    /// <summary>
    /// 获取帧动画资源
    /// </summary>
    public List<Sprite> GetDynamicImage(string key)
    {
        // 按需加载资源
        if (!allFrameDic.ContainsKey(key))
        {
            LoadFrameSprites(FrameAnimationConfig.Get(key));
        }
        
        if (allFrameDic.TryGetValue(key, out var list))
        {
            return list;
        }
        return null;
    }

    /// <summary>
    /// 检查是否包含指定帧动画
    /// </summary>
    public bool ContainsDynamicImage(string key)
    {
        return FrameAnimationConfig.HasKey(key);
    }
    
    
    /// <summary>
    /// 预加载指定帧动画
    /// </summary>
    public void PreloadDynamicImage(string key)
    {
        if (!allFrameDic.ContainsKey(key))
        {
            LoadFrameSprites(FrameAnimationConfig.Get(key));
        }
    }
}