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

// 用来为AssetUpdateDownloader提供计时更新的工具
// 这个全游戏绝对存在的实例，因此用他探测是否结束游戏
public class AssetUpdateDownloaderTick : MonoBehaviour
{
    public static AssetUpdateDownloaderTick instance;
    public event UnityAction onUpdate;
    private readonly List<DownloadTimer> _timers = new List<DownloadTimer>();
    /// <summary>
    ///     是否游戏已经退出，处理一些关闭时调用OnDestroy产生的报错
    /// </summary>
    public static bool applicationQuit { get; private set; }
    public static void CreateInstance()
    {
        if (!instance)
        {
            var gameObject = new GameObject("AssetUpdateDownloaderTick");
            instance = gameObject.AddComponent<AssetUpdateDownloaderTick>();
        }
    }
    
    private void Awake()
    {
        DontDestroyOnLoad(gameObject);
    }
    
    private void OnApplicationQuit()
    {
        applicationQuit = true;
    }
    
    #region Load Stream Asset - 加载配置表等非AssetBundle资源
    public delegate void LoadStreamAssetCallBack(WWW www);

    public void LoadStreamingAsset(string uri, LoadStreamAssetCallBack callBack)
    {
        uri = Application.streamingAssetsPath.Open(uri);
#if UNITY_EDITOR || !UNITY_ANDROID
        uri = "file://" + uri;
#endif
        StartCoroutine(LoadWWW(uri, callBack));
    }

    private static IEnumerator LoadWWW(string uri, LoadStreamAssetCallBack callBack)
    {
        var www = new WWW(uri);
        yield return www;
        if (!string.IsNullOrEmpty(www.error))
            Debug.LogError("Load streaming assets error: " + www.error + "\n" + uri);
        if (callBack != null)
            callBack(www);
        www.Dispose();
    }

    #endregion
    
    private void LateUpdate()
    {
        if (onUpdate != null)
            onUpdate();
        for (var i = _timers.Count - 1; i >= 0; i--)
        {
            var timer = _timers[i];
            if (Time.realtimeSinceStartup > timer.time)
            {
                _timers.RemoveAt(i);
                if (timer.callback != null)
                    timer.callback.Invoke();
            }
        }
    }

    public DownloadTimer AddTimer(float delay, UnityAction callback)
    {
        var timer = _timers.Find(a => a.callback == callback);
        if (timer == null)
        {
            timer = new DownloadTimer(callback);
            _timers.Add(timer);
        }
        timer.time = Time.realtimeSinceStartup + delay;
        return timer;
    }

    public void RemoveTimer(UnityAction callback)
    {
        var i = _timers.FindIndex(a => a.callback == callback);
        if (i >= 0)
            _timers.RemoveAt(i);
    }

    public class DownloadTimer
    {
        public readonly UnityAction callback;
        public float time;
        
        public DownloadTimer(UnityAction callback)
        {
            this.callback = callback;
        }
    }
}