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

namespace Engine.CLoader
{
    /// <summary>客户端加载对象处理器器</summary>
    public class CLoaderManager : MonoBehaviour
    {

        #region 单利
        private static CLoaderManager instance;
        /// <summary>单利对象</summary>
        public static CLoaderManager GetInstance()
        {
            if (instance == null)
            {
                GameObject managerGO = new GameObject();
                DontDestroyOnLoad(managerGO);
                managerGO.name = "CLoaderManager";
                instance = managerGO.AddComponent<CLoaderManager>();
            }
            return instance;
        }
        #endregion

        /// <summary>缓存的loader对象列表</summary>
        private List<CLoaderAB> catchLoaderList = new List<CLoaderAB>();
        /// <summary>当前缓存的资源</summary>
        private List<CAssetsInfo> catchAssetsList = new List<CAssetsInfo>();

        /// <summary>现在中的loader个数</summary>
        private int loadIngLoaderCount = 0;
        /// <summary>是否初始化了处理器</summary>
        public bool IsInitManager = false;

        /// <summary>空构造函数</summary>
        public CLoaderManager() { }

        /// <summary>初始化处理器</summary>
        public void InitManager(CLoaderData configData)
        {
            //创建Loader对象
            CreateCatchLoader();
            //加载配置文件
            this.LoadAssets(configData);
        }

        /// <summary>预先创建加载对象</summary>
        private void CreateCatchLoader()
        {
            for (int i = 0; i < CLoaderConst.CLoaderMaxCount; i++)
            {
                catchLoaderList.Add(new CLoaderAB());
            }
        }

		/// <summary>回收内存</summary>
		public void GC()
		{
			//Resources.UnloadUnusedAssets ();
		}

        /// <summary>添加资源</summary>
        private void AddAssets(CLoaderAB loader)
        {
            CAssetsInfo assetsInfo = FindEmptyAssets();
            if(assetsInfo==null)
            {
                assetsInfo = new CAssetsInfo();
                catchAssetsList.Add(assetsInfo);
            }

            assetsInfo.assetsBundle = loader.assetsBundle;
            assetsInfo.assetsName = loader.assetsName;
            assetsInfo.isEmpty = false;
        }

        /// <summary>查找获得名称的资源包数据</summary>
        internal CAssetsInfo GetAssets(string assetsName)
        {
            CAssetsInfo assetsInfo = this.FindAssetsByAssetsName(assetsName);
            if (assetsInfo != null)
            {
                assetsInfo.AddUseCount();
            }
            return assetsInfo;
        }

        /// <summary>查找一个空的CAssetsInfo</summary>
        private CAssetsInfo FindEmptyAssets()
        {
            for (int i = 0; i < catchAssetsList.Count; i++)
            {
                if(catchAssetsList[i].isEmpty)
                {
                    return catchAssetsList[i];
                }
            }
            return null;
        }

        /// <summary>查找指定名称的资源</summary>
        private CAssetsInfo FindAssetsByAssetsName(string assetsName)
        {
            for (int i = 0; i < catchAssetsList.Count; i++)
            {
                if (catchAssetsList[i].assetsName == assetsName)
                {
                    return catchAssetsList[i];
                }
            }
            return null;
        }

        /// <summary>等待执行的loaderData，下载逻辑是两层队列，这是第一层队列</summary>
        private List<CLoaderData> waitLoadDataList = new List<CLoaderData>();
        /// <summary>实际需要下载的资源</summary>
        private List<string> waitNeedLoadAssets = new List<string>();

        /// <summary>加载资源</summary>
        public void LoadAssets(CLoaderData loaderData)
        {
            //添加到队列
            waitLoadDataList.Add(loaderData);
            //执行一个LoadData
            if (waitLoadDataList.Count == 1)
            {
                this.LoadFistLoaderData();
            }
        }

        /// <summary>加载第一个CLoaderData</summary>
        private void LoadFistLoaderData()
        {
            if(waitLoadDataList.Count==0)
            { return; }

            //获得数据
            CLoaderData loaderData = waitLoadDataList[0];
            //循环长度
            int forLeng = 0;
            //不是配置文件
            if (loaderData.assetsType != AssetsType.Config)
            {
                //如果有依赖的包先下载依赖的包
                List<CAssetsConfigInfo> assetsConfigList = loaderData.AssetsConfigList;
                forLeng = assetsConfigList.Count;
                bool isDataComplete = false;
                for (int i = 0; i < forLeng; i++)
                {
                    if(LoadDepAssets(assetsConfigList[i], assetsConfigList[i]))
                    {
                        isDataComplete = true;
                        break;
                    }
                }

                if(isDataComplete)
                {
                    OnFirstLoaderComplete();
                }
            }
            //资源配置文件，这时还获取不到资源的配置数据
            else
            {
                forLeng = loaderData.listAssetsName.Count;
                for (int i = 0; i < forLeng; i++)
                {
                    this.AddNeedLoadAssets(loaderData.listAssetsName[i]);
                }
            }
        }

        /// <summary>递归次数，避免死循环不方便查找错误，如果递归超过20层，报错不在递归下去</summary>
        private int recursiveCount = 0;
        /// <summary>下载依赖的包</summary>
        private bool LoadDepAssets(CAssetsConfigInfo assetsConfigInfo, CAssetsConfigInfo debugInfo)
        {
            //增加递归次数
            recursiveCount++;
            //如果递归超过20层，报错不在递归下去
            if(recursiveCount>20)
            {
#if UNITY_EDITOR
                CDebug.LogError("包的依赖关系层次超过20层 name=" + debugInfo.assetsName);
#endif
                return false;
            }

            //依赖项依赖的资源 循环递归，如果存在循环依赖关系这里会死循环
            if(assetsConfigInfo==null)
            {
                CDebug.Log("assetsConfigInfo==null");
                return false;
            }
            int depCount = assetsConfigInfo.AssetsDepInfoList.Count;
            for (int i = 0; i < depCount; i++)
            {
                //递归下载
                LoadDepAssets(assetsConfigInfo.AssetsDepInfoList[i], debugInfo);
            }

            //添加到需要的下载的队列
            bool isDataComplete = this.AddNeedLoadAssets(assetsConfigInfo.assetsName);
            //减少递归次数
            recursiveCount--;

            return isDataComplete;
        }

        /// <summary>添加需要下载的资源</summary>
        private bool AddNeedLoadAssets(string needAssets)
        {
            //是否已经下载完毕
            CAssetsInfo assetsInfo = this.GetAssets(needAssets);
            if (assetsInfo!=null)
            {
                waitLoadDataList[0].UpdateProgress(assetsInfo.assetsName, 100);
                return waitLoadDataList[0].ChectLoadComplete(assetsInfo);
            }

            //是否已经在队列中
            if (waitNeedLoadAssets.IndexOf(needAssets)!=-1)
            {
                return false;
            }

            //是否在下载中
            for (int i = 0; i < CLoaderConst.CLoaderMaxCount; i++)
            {
                if (!catchLoaderList[i].IsLoadIng)
                { continue; }
                
                if(catchLoaderList[i].assetsName == needAssets)
                {
                    return false;
                }
            }

            //添加队列
            waitNeedLoadAssets.Add(needAssets);
            //检查是否有空闲的loader，如果有下载队列中的资源
            if(waitNeedLoadAssets.Count==1)
            {
                this.CheckStartLoad();
            }
            return false;
        }

        /// <summary>检查是否可以开始下载资源</summary>
        private void CheckStartLoad()
        {
            //没有需要下载的资源了
            if (waitNeedLoadAssets.Count == 0)
            {
                return;
            }

            string assetsName = "";
            for (int i = 0; i < CLoaderConst.CLoaderMaxCount; i++)
            {
                if (catchLoaderList[i].IsLoadIng)
                { continue; }

                //真正的开始下载 下载进度和是否下载完成全都在update函数中检查
                assetsName = waitNeedLoadAssets[0];
                waitNeedLoadAssets.RemoveAt(0);
                loadIngLoaderCount++;
                catchLoaderList[i].StartLoad(CLoaderConst.AssetsBundleURL + assetsName, assetsName);

                //没有需要下载的资源了
                if(waitNeedLoadAssets.Count==0)
                {
                    break;
                }
            }
        }

        /// <summary>帧频函数</summary>
        private void Update()
        {
            //检查场景加载
            CheckSceneAsync();

            //没有资源在下载不需要检查
            if(loadIngLoaderCount==0)
            { return; }

            //整个的loaderdata是否下载完毕，第一层队列是否下载完毕
            bool isDataComplete = false;
            //第二层队列是否有loader下载完毕
            bool isBeLoadComplete = false;

            CLoaderData loaderData = waitLoadDataList[0];
            CLoaderAB loader = null;
            for (int i = 0; i < CLoaderConst.CLoaderMaxCount; i++)
            {
                loader = catchLoaderList[i];
                if (!loader.IsLoadIng)
                { continue; }

                loader.OnUpdate();

                //下载完成
                if(loader.IsLoadComplete)
                {
                    //让资源入库
                    this.AddAssets(loader);
                    //检查DataLoader整体是否下载完毕
                    isDataComplete = loaderData.ChectLoadComplete(this.GetAssets(loader.assetsName));
                    //重置loader对象
                    loader.Reset();
                    //标记有loader空闲了
                    isBeLoadComplete = true;
                    //修改使用中的loader个数
                    loadIngLoaderCount--;

                    //资源下载完毕 跳出循环 执行回调和下一个LoaderData
                    if (isDataComplete)
                    {
                        break;
                    }
                }
                else
                {
                    loaderData.UpdateProgress(loader.assetsName, loader.LoadProgress);
                }
            }

            //执行回调和下一个LoaderData
            if(isDataComplete)
            {
                OnFirstLoaderComplete();
            }
            //第二层队列是否有loader下载完毕
            else if (isBeLoadComplete)
            {
                this.CheckStartLoad();
            }
        }

        /// <summary>LoadData下载完毕</summary>
        private void OnFirstLoaderComplete()
        {
            CLoaderData loaderData = waitLoadDataList[0];
            //从队列中删除第一个资源
            waitLoadDataList.RemoveAt(0);
            //执行回调
            loaderData.OnCompleteCallBack();
            //继续下载
            this.LoadFistLoaderData();
        }

        /// <summary>场景加载对象</summary>
        private AsyncOperation mSceneAsync = null;
        /// <summary>加载完成回调</summary>
        private OnDelegateLoadSceneComplete OnLoadSceneComplete;
        /// <summary>当前场景名称</summary>
        private string strCurSceneName = "";
        /// <summary>当前场景名称</summary>
        public string CurSceneName
        {
            get { return strCurSceneName; }
        }

        private string strLoadingSceneName = "";
        /// <summary>加载场景</summary>
        public void LoadScene(string sceneName, OnDelegateLoadSceneComplete onLoadSceneComplete)
        {
            //当前场景就是需要加载的场景
            if (sceneName == strCurSceneName)
            {
                if (onLoadSceneComplete != null)
                {
                    onLoadSceneComplete();
                }
                return;
            }

            //正在加载其他场景
            if (mSceneAsync!=null)
            {
                CDebug.LogError("重复调用加载场景逻辑！");
                return;
            }

            OnLoadSceneComplete = onLoadSceneComplete;
            strLoadingSceneName = sceneName;
			mSceneAsync = UnityEngine.SceneManagement.SceneManager.LoadSceneAsync (sceneName);
		}

        /// <summary>检查异步加载场景是否完成</summary>
        private void CheckSceneAsync()
        {
            //如果刚刚加载完成，等待一帧在返回true
            if (mSceneAsync != null && mSceneAsync.isDone)
            {
                mSceneAsync = null;
                strCurSceneName = strLoadingSceneName;

                if (OnLoadSceneComplete != null)
                {
					OnDelegateLoadSceneComplete onCallBack = OnLoadSceneComplete;
					OnLoadSceneComplete = null;
					onCallBack();
					onCallBack = null;
                }
            }
        }
    }
}