using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using UnityEngine;
using UnityEngine.Networking;
using UnityEngine.UI;

public class TextureLoadHelp : MonoBehaviour
{
    public static TextureLoadHelp _Instance;

    private Dictionary<string, TempTexData> tempTexList;

    private Dictionary<long, Material> waitLoadImgActionList;
    private Dictionary<long, RawImage> waitLoadImgActionList_RawImg;

    
    public float currentTotalSize = 0;
    public float maxSize = 500; //图片缓存-m

    private Dictionary<string, AssetBundle> loadDoneABList;
    private Dictionary<string, int> loadingABList;

    public Texture map_def;
    
    //临时存的封面图
    public Texture[] tempTextures;
    public string[] tempTextureName;

    public Texture GetTempTexture(string name)
    {
        int index = -1;
        for (int i = 0; i < tempTextureName.Length; i++)
        {
            if (tempTextureName[i].Equals(name))
            {
                index = i;
                break;
            }
        }
        if (index != -1)
        {
            return tempTextures[index];
        }
        else
        {
            return null;
        }
    }

    private void Awake()
    {
        _Instance = this;
        tempTexList = new Dictionary<string, TempTexData>();
        waitLoadImgActionList = new Dictionary<long, Material>();
        waitLoadImgActionList_RawImg = new Dictionary<long, RawImage>();
        loadDoneABList = new Dictionary<string, AssetBundle>();
        loadingABList = new Dictionary<string, int>();
    }

    /// <summary>
    /// 加载图片
    /// </summary>
    /// <param name="path"></param>
    /// <param name="rawImg"></param>
    /// <returns></returns>
    public long LoadTexFromUrl(string path, RawImage rawImg)
    {
        long loadId = GetDownId();
        //Debug.Log("下载图片:"+loadId);
        // if (CheckCache(path))
        // {
        //     rawImg.texture = LoadFromCache(path);
        //     return 0;
        // }

        if (tempTexList.TryGetValue(path, out var value))
        {
            value.isUsing = true;
            rawImg.texture = value.tex;
            loadId = 0;
        }
        else
        {
            waitLoadImgActionList_RawImg.Add(loadId, rawImg);
            StartCoroutine(DownLoadTex_Raw(path, loadId));
        }

        return loadId;
    }

    public long LoadTexFromUrl_AB(string ab_Name, string FileName, Material mat)
    {
        if (tempTexList.TryGetValue(FileName, out var value))
        {
            value.isUsing = true;
            mat.mainTexture = value.tex;
            return 0;
        }

        mat.mainTexture = map_def;
        long loadId = GetDownId();
        waitLoadImgActionList.Add(loadId, mat);
        StartCoroutine(DownLoadTex_AB(ab_Name, FileName, loadId));
        return loadId;
    }

    /// <summary>
    /// 取消加载
    /// </summary>
    /// <param name="loadId"></param>
    public void CancelLoad(long loadId)
    {
        if (waitLoadImgActionList.ContainsKey(loadId))
        {
            waitLoadImgActionList.Remove(loadId);
        }
    }

    /// <summary>
    /// 标记缓存图片为未使用
    /// </summary>
    /// <param name="path"></param>
    public void UnUsingTex(string path)
    {
        if (tempTexList.TryGetValue(path, out TempTexData disposeData))
        {
            disposeData.isUsing = false;
        }
        else
        {
            Debug.Log($"不存在缓存:{path}");
        }
    }

    IEnumerator DownLoadTex_AB(string ab_Name, string fileName, long loadId)
    {
        if (loadingABList.ContainsKey(ab_Name))
        {
            //Debug.Log($"{ab_Name} downloading...wait");
            yield return new WaitUntil(() => loadingABList[ab_Name] > 0);
            // if (loadingABList.ContainsKey(ab_Name))
            // {
            //     loadingABList.Remove(ab_Name);
            // }
        }

        AssetBundle tempAb;
        Texture2D tex;
        if (loadDoneABList.TryGetValue(ab_Name, out var value))
        {
            tempAb = value;
            tex = tempAb.LoadAsset<Texture2D>(fileName);
            if (waitLoadImgActionList.TryGetValue(loadId, out Material targetMat))
            {
                if (targetMat != null && tex != null)
                {
                    targetMat.mainTexture = tex;
                }
                else
                {
                    if (targetMat == null)
                    {
                        Debug.Log($"{fileName} 材质球不存在");
                    }

                    if (tex == null)
                    {
                        Debug.Log($"{fileName} 图片不存在");
                    }
                }

                waitLoadImgActionList.Remove(loadId);
            }
        }
        else
        {
            //添加到正在下载
            loadingABList.TryAdd(ab_Name, 0);
#if UNITY_EDITOR
            WWW www = new WWW($"{Application.streamingAssetsPath}/{ab_Name}");
#else
            WWW www = WWW.LoadFromCacheOrDownload($"{Application.streamingAssetsPath}/{ab_Name}",0);
#endif
            yield return www;
            if (www.isDone)
            {
                tempAb = www.assetBundle;
                loadDoneABList.Add(ab_Name, tempAb);

                loadingABList[ab_Name] = 1;
                tex = tempAb.LoadAsset<Texture2D>(fileName);
                tempTexList.TryAdd(fileName, new TempTexData()
                {
                    loadTime = GetTimeStamp(),
                    name = fileName,
                    tex = tex,
                    size = 0,
                    isUsing = true
                });
                if (waitLoadImgActionList.TryGetValue(loadId, out Material targetMat))
                {
                    if (targetMat != null && tex != null)
                    {
                        targetMat.mainTexture = tex;
                    }
                    else
                    {
                        if (targetMat == null)
                        {
                            Debug.Log($"{fileName} 材质球不存在");
                        }

                        if (tex == null)
                        {
                            Debug.Log($"{fileName} 图片不存在");
                        }
                    }

                    waitLoadImgActionList.Remove(loadId);
                }
            }
            else
            {
                loadingABList[ab_Name] = 2;
                Debug.LogError($"{ab_Name}下载失败：{www.error}");
            }

            www.Dispose();
        }
    }

    IEnumerator DownLoadTex(string path, long loadId)
    {
        UnityWebRequest www = UnityWebRequestTexture.GetTexture(path);
        yield return www.SendWebRequest();
        if (www.downloadHandler.isDone)
        {
            if (waitLoadImgActionList.ContainsKey(loadId))
            {
                var texture = ((DownloadHandlerTexture)www.downloadHandler).texture;
                float tempSize = GetSize_m(www.downloadedBytes);
                tempTexList.TryAdd(path, new TempTexData()
                {
                    loadTime = GetTimeStamp(),
                    name = path,
                    tex = texture,
                    size = tempSize,
                    isUsing = true
                });
                currentTotalSize += tempSize;
                CheckSize();
                if (waitLoadImgActionList.TryGetValue(loadId, out Material targetMat))
                {
                    if (targetMat != null)
                    {
                        targetMat.mainTexture = texture;
                    }

                    waitLoadImgActionList.Remove(loadId);
                }

                SaveInCache(path, www.downloadHandler.data);
            }
            else
            {
                www.disposeDownloadHandlerOnDispose = true;
                Debug.Log(path + " 下载已取消");
            }
        }
        else
        {
            Debug.LogError($"{path}下载失败：{www.downloadHandler.error}");
        }

        www.Dispose();
    }

    IEnumerator DownLoadTex_Raw(string path, long loadId)
    {
        WWW www = new WWW(path);

        yield return www;
        if (www.isDone)
        {
            if (waitLoadImgActionList_RawImg.ContainsKey(loadId))
            {
                var texture = www.texture;
                float tempSize = GetSize_m((ulong)www.bytesDownloaded);
                tempTexList.TryAdd(path, new TempTexData()
                {
                    loadTime = GetTimeStamp(),
                    name = path,
                    tex = texture,
                    size = tempSize,
                    isUsing = true
                });
                currentTotalSize += tempSize;
                CheckSize();
                if (waitLoadImgActionList_RawImg.TryGetValue(loadId, out RawImage rawImage))
                {
                    if (rawImage != null)
                    {
                        rawImage.texture = texture;
                    }

                    waitLoadImgActionList_RawImg.Remove(loadId);
                }
            }
            else
            {
                Debug.Log(path + " 下载已取消");
            }
        }
        else
        {
            Debug.LogError($"{path}下载失败：{www.error}");
        }

        www.Dispose();
    }

    private void SaveInCache(string url, byte[] data)
    {
        string fileName = Path.GetFileName(url);
        string path = Application.persistentDataPath;
        File.WriteAllBytes(path + fileName, data);
        Debug.Log($"缓存:{path}{fileName}");
    }

    private Texture2D LoadFromCache(string url)
    {
        string fileName = Path.GetFileName(url);
        string path = Application.persistentDataPath;
        byte[] texBytes = File.ReadAllBytes(path + fileName);
        currentTotalSize += GetSize_m((ulong)texBytes.Length);
        Texture2D tempTex = new Texture2D(2, 2);
        tempTex.LoadImage(texBytes);
        tempTex.Apply();
        return tempTex;
    }

    // private bool CheckCache(string url)
    // {
    //     string fileName = Path.GetFileName(url);
    //     string path = Application.persistentDataPath;
    //     //Debug.Log($"CaChe:{path}");
    //     return File.Exists(path + fileName);
    // }

    public void CheckSize()
    {
        if (currentTotalSize >= maxSize)
        {
            List<TempTexData> values = tempTexList.Values.ToList();
            values.Sort();
            for (int i = 0; i < values.Count; i++)
            {
                if (!values[i].isUsing)
                {
                    if (tempTexList.TryGetValue(values[i].name, out TempTexData disposeData))
                    {
                        disposeData.tex = null;
                        currentTotalSize -= disposeData.size;
                        tempTexList.Remove(disposeData.name);
                    }
                }

                if (currentTotalSize < maxSize)
                {
                    break;
                }
            }

            if (currentTotalSize >= maxSize)
            {
                Debug.Log($"临时图片已超过限制大小且无可释放项！！！：{currentTotalSize}/{maxSize}");
            }
        }
    }

    /// <summary>
    /// 清空全部缓存
    /// </summary>
    public void ClearAllTempTex()
    {
        List<TempTexData> values = tempTexList.Values.ToList();
        for (int i = 0; i < values.Count; i++)
        {
            if (tempTexList.TryGetValue(values[i].name, out TempTexData disposeData))
            {
                disposeData.tex = null;
                currentTotalSize -= disposeData.size;
                tempTexList.Remove(disposeData.name);
            }
        }

        waitLoadImgActionList.Clear();
        tempTexList.Clear();
        Resources.UnloadUnusedAssets();
        GC.Collect();
    }

    private long GetDownId()
    {
        long id = ((DateTime.Now.ToUniversalTime().Ticks - 621355968000000000) / 10000000);
        while (waitLoadImgActionList.ContainsKey(id))
        {
            id++;
        }

        return id;
    }

    private long GetTimeStamp()
    {
        return (DateTime.Now.ToUniversalTime().Ticks - 621355968000000000) / 10000000;
    }

    private float GetSize_m(ulong size_b)
    {
        return (size_b * 1.0f / (1024.0f * 1024.0f));
    }
}


public class TempTexData : IComparable<TempTexData>
{
    public string name;
    public Texture tex;
    public long loadTime;
    public float size;
    public bool isUsing = true;

    public int CompareTo(TempTexData other)
    {
        if (other.loadTime < loadTime)
        {
            return 1;
        }

        if (other.loadTime == loadTime)
        {
            return 0;
        }

        return -1;
    }
}