using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Net.Http;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using Update.Utils;

namespace Update.Services
{
    public static class Update
    {

        public delegate void DeleUpdateProgress(string step, int nowP, int maxP);
        public delegate void DeleAfterUpdateProgress(bool ok, string error);
        private static readonly string DEFAULT_DOWNLOAD_PATH = Path.Combine(Environment.CurrentDirectory, "tmp");
        private static readonly List<string> IGNORE_PATHS = new List<string>()
        {
            "update"
        };

        public struct UpdateInfo
        {
            public string MD5 { get; set; }
            public double Version { get; set; }
        }

        public static async Task UpdateApplication(string url, string targetPath, DeleUpdateProgress updateProgress, DeleAfterUpdateProgress afterUpdateProgress, string tmpPath = null)
        {
            await Task.Factory.StartNew(async () =>
            {
                int maxSteps = 7, step = 1;
                if (string.IsNullOrEmpty(tmpPath))
                {
                    tmpPath = DEFAULT_DOWNLOAD_PATH;
                }
                string localFile = Path.Combine(tmpPath, Path.GetFileName(url));
                string uncompressPath = Path.Combine(tmpPath, "tmp");
                void clearCache()
                {
                    Task.Run(async () => { await ClearCache(uncompressPath, localFile); });
                }
                //await ClearTempPath(uncompressPath);
                updateProgress("获取更新参数", step++, maxSteps);
                UpdateInfo info = await GetUpdateInfo(url);
                if (info.Version < 1 || string.IsNullOrEmpty(info.MD5))
                {
                    AfterUpdateProgressEvent(afterUpdateProgress, false, "获取更新参数失败！", clearCache);
                    return;
                }
                updateProgress("下载", step++, maxSteps);
                if (!await Download(url, localFile))
                {
                    AfterUpdateProgressEvent(afterUpdateProgress, false, "下载失败！", clearCache);
                    return;
                }
                updateProgress("校验", step++, maxSteps);
                if (!CheckFileMd5(localFile, info.MD5))
                {
                    AfterUpdateProgressEvent(afterUpdateProgress, false, "校验失败！", clearCache);
                    return;
                }
                updateProgress("解压", step++, maxSteps);
                if (!await UnCompress(localFile, uncompressPath))
                {
                    AfterUpdateProgressEvent(afterUpdateProgress, false, "解压失败！", clearCache);
                    return;
                }
                updateProgress("更新", step++, maxSteps);
                if (!await CopyDirectory(uncompressPath, targetPath))
                {
                    updateProgress("更新失败", step, maxSteps);
                    AfterUpdateProgressEvent(afterUpdateProgress, false, "更新失败！", clearCache);
                    return;
                }
                updateProgress("清理缓存", step++, maxSteps);
                if (!await ClearCache(uncompressPath, localFile))
                {
                    updateProgress("清理缓存失败", step, maxSteps);
                    AfterUpdateProgressEvent(afterUpdateProgress, true, "更新完成，清理缓存失败！", null);
                }
                else
                {
                    updateProgress("更新完成", step++, maxSteps);
                    AfterUpdateProgressEvent(afterUpdateProgress, true, "更新完成！", null);
                }
            });
        }

        private static void AfterUpdateProgressEvent(DeleAfterUpdateProgress afterUpdateProgress, bool res, string error, Action task)
        {
            afterUpdateProgress.Invoke(res, error);
            task?.Invoke();
        }

        private static async Task<UpdateInfo> GetUpdateInfo(string url)
        {
            UpdateInfo info = new UpdateInfo();
            try
            {
                url = Regex.Replace(url, "\\.[^.]{2,5}$", ".txt", RegexOptions.IgnoreCase);
                HttpResponseMessage response = await Http.Fetch(new Http.Request(url, Http.Method.Get));
                if (response.IsSuccessStatusCode)
                {
                    string txt = await response.Content.ReadAsStringAsync();
                    info = Utils.Json.Decode<UpdateInfo>(txt);
                }
            }
            catch
            {

            }
            return info;
        }

        private static bool CheckFileMd5(string localFileName, string md5)
        {
            return FileExtensions.FileMd5(localFileName) == md5;
        }

        private static async Task<bool> ClearTempPath(string targetPath)
        {
            try
            {
                await Task.Run(() =>
                {
                    DirectoryInfo di = new DirectoryInfo(targetPath);
                    if (di.Exists)
                    {
                        di.Delete(true);
                    }
                    FileExtensions.CheckDirectory(targetPath, true);
                });
                return true;
            }
            catch
            {
                return false;
            }

        }


        private static async Task<bool> Download(string url, string localFilename)
        {
            try
            {
                HttpResponseMessage response = await Utils.Http.Fetch(new Utils.Http.Request(url, Utils.Http.Method.Get));
                if (response != null && response.IsSuccessStatusCode)
                {
                    var bytes = await response.Content.ReadAsByteArrayAsync();
                    FileExtensions.WriteBytes(localFilename, bytes);
                }
                return true;
            }
            catch
            {
                return false;
            }

        }

        private static async Task<bool> UnCompress(string localFilename, string targetPath)
        {
            bool r = false;
            try
            {
                r = await Task.Run(async () =>
                {
                    bool res = await ClearTempPath(targetPath);
                    if (res)
                    {
                        ZipFile.ExtractToDirectory(localFilename, targetPath);
                        res = true;
                    }
                    return res;
                });
            }
            catch
            {
            }
            return r;
        }

        private static async Task<bool> CopyDirectory(string srcPath, string dstPath)
        {
            bool copyDirectory(string sp, string dp)
            {
                string np;
                try
                {
                    DirectoryInfo dir = new DirectoryInfo(sp);
                    FileSystemInfo[] fileinfo = dir.GetFileSystemInfos();  //获取目录下（不包含子目录）的文件和子目录
                    foreach (FileSystemInfo i in fileinfo)
                    {
                        np = Path.Combine(dp, i.Name);
                        if (i is DirectoryInfo)     //判断是否文件夹
                        {
                            if (!Directory.Exists(np))
                            {
                                Directory.CreateDirectory(np);   //目标目录下不存在此文件夹即创建子文件夹
                            }
                            if (!IsIgnoreDirectory(i.FullName, srcPath))
                            {
                                // 判断是否是忽略目录
                                copyDirectory(i.FullName, np);    //递归调用复制子文件夹
                            }
                        }
                        else
                        {
                            File.Copy(i.FullName, np, true);      //不是文件夹即复制文件，true表示可以覆盖同名文件
                        }
                    }
                    return true;
                }
                catch
                {
                    return false;
                }
            }
            return await Task.Run(() => { return copyDirectory(srcPath, dstPath); });
        }

        private static bool IsIgnoreDirectory(string p, string srcRootPath)
        {
            bool res = false;
            Uri a = new Uri(p), b;
            foreach (string s in IGNORE_PATHS)
            {
                b = new Uri(Path.Combine(srcRootPath, s));
                res = a == b;
                if (res)
                {
                    break;
                }
            }
            return res;
        }


        private static async Task<bool> ClearCache(string cachePath, string cacheUpdateFile)
        {
            bool res = false;
            await Task.Run(() =>
            {
                try
                {
                    DirectoryInfo di = new DirectoryInfo(cachePath);
                    if (di.Exists)
                    {
                        di.Delete(true);
                    }
                    if (File.Exists(cacheUpdateFile))
                    {
                        File.Delete(cacheUpdateFile);
                    }
                    res = true;
                }
                catch { }
            });
            return res;
        }

    }
}