using System.Diagnostics;
using System.Net.Http;
using System.Reflection;
using NewLife.Http;
using NewLife.Log;
using NewLife.Reflection;
using NewLife.Web;

namespace NewLife.Net;

/// <summary>升级更新</summary>
/// <remarks>
/// 优先比较版本Version，再比较时间Time。
/// 自动更新的难点在于覆盖正在使用的exe/dll文件，通过改名可以解决。
/// </remarks>
public class Upgrade
{
    #region 属性
    /// <summary>名称</summary>
    public String Name { get; set; }

    /// <summary>服务器地址</summary>
    public String Server { get; set; }

    /// <summary>版本</summary>
    public Version? Version { get; set; }

    /// <summary>本地编译时间</summary>
    public DateTime Time { get; set; }

    /// <summary>更新目录</summary>
    public String UpdatePath { get; set; } = "Update";

    /// <summary>目标目录</summary>
    public String DestinationPath { get; set; } = ".";

    /// <summary>超链接信息</summary>
    public Link? Link { get; set; }

    /// <summary>缓存文件。同名文件不再下载，默认false</summary>
    public Boolean CacheFile { get; set; } = true;

    /// <summary>更新源文件</summary>
    public String? SourceFile { get; set; }
    #endregion

    #region 构造
    /// <summary>实例化一个升级对象实例，获取当前应用信息</summary>
    public Upgrade()
    {
        Name = nameof(Upgrade);

        var asm = Assembly.GetEntryAssembly();
        if (asm != null)
        {
            var name = asm.GetName();
            if (name != null)
            {
                Version = name.Version;
                Name = name.Name ?? nameof(Upgrade);
            }

            var ax = AssemblyX.Create(asm);
            if (ax != null) Time = ax.Compile;
        }

        Server = NewLife.Setting.Current.PluginServer;
    }
    #endregion

    #region 方法
    /// <summary>获取版本信息，检查是否需要更新</summary>
    /// <returns></returns>
    public Boolean Check()
    {
        // 删除备份文件
        DeleteBackup(DestinationPath);

        var url = Server;

        WriteLog("检查资源包 {0}", url);

        var web = CreateClient();
        var html = web.GetString(url);
        var links = Link.Parse(html, url, item => !item.Name.IsNullOrEmpty() && item.Name.ToLower().Contains(Name.ToLower()));
        if (links == null || links.Length == 0)
        {
            WriteLog("找不到资源包");
            return false;
        }

        // 先比较版本
        if (Version > new Version(0, 0))
        {
            var link = links.OrderByDescending(e => e.Version).FirstOrDefault()!;
            if (link.Version > Version)
            {
                Link = link;
                WriteLog("线上版本[{0}]较新 {1}>{2}", link.FullName, link.Version, Version);
            }
            else
                WriteLog("线上版本[{0}]较旧 {1}<={2}", link.FullName, link.Version, Version);
        }
        // 再比较时间
        else
        {
            var link = links.OrderByDescending(e => e.Time).FirstOrDefault()!;
            // 只有文件时间大于编译时间才更新，需要考虑文件编译后过一段时间才打包
            if (link.Time > Time.AddMinutes(10))
            {
                Link = link;
                WriteLog("线上版本[{0}]较新 {1}>{2}", link.FullName, link.Time, Time);
            }
            else
                WriteLog("线上版本[{0}]较旧 {1}<={2}", link.FullName, link.Time, Time);
        }

        return Link != null;
    }

    /// <summary>开始更新</summary>
    public void Download()
    {
        var link = Link ?? throw new Exception("No new version available!");
        if (link.Url.IsNullOrEmpty()) throw new Exception("The upgrade package address is invalid!");

        Download(link.Url, link.FullName);
    }

    /// <summary>开始更新</summary>
    /// <param name="url">下载源</param>
    /// <param name="fileName">文件名</param>
    public void Download(String url, String? fileName)
    {
        // 如果更新包不存在，则下载
        var file = !fileName.IsNullOrEmpty() ?
            UpdatePath.CombinePath(fileName).GetBasePath() :
            Path.GetTempFileName();
        if (!CacheFile && File.Exists(file)) File.Delete(file); ;
        if (!File.Exists(file))
        {
            WriteLog("准备下载 {0} 到 {1}", url, file);

            var sw = Stopwatch.StartNew();

            var web = CreateClient();
            TaskEx.Run(() => web.DownloadFileAsync(url, file)).Wait();

            sw.Stop();
            WriteLog("下载完成！大小{0:n0}字节，耗时{1:n0}ms", file.AsFile().Length, sw.ElapsedMilliseconds);
        }

        SourceFile = file;
    }

    /// <summary>开始更新</summary>
    /// <param name="url">下载源</param>
    /// <param name="fileName">文件名</param>
    /// <param name="cancellationToken">取消通知</param>
    public async Task DownloadAsync(String url, String fileName, CancellationToken cancellationToken)
    {
        // 如果更新包不存在，则下载
        var file = UpdatePath.CombinePath(fileName).GetBasePath();
        if (!CacheFile && File.Exists(file)) File.Delete(file); ;
        if (!File.Exists(file))
        {
            WriteLog("准备下载 {0} 到 {1}", url, file);

            var sw = Stopwatch.StartNew();

            var web = CreateClient();
            await web.DownloadFileAsync(url, file, cancellationToken);

            sw.Stop();
            WriteLog("下载完成！大小{0:n0}字节，耗时{1:n0}ms", file.AsFile().Length, sw.ElapsedMilliseconds);
        }

        SourceFile = file;
    }

    /// <summary>检查并执行更新操作</summary>
    public Boolean Update()
    {
        // 删除备份文件
        DeleteBackup(DestinationPath);

        var file = SourceFile;

        if (file.IsNullOrEmpty() || !File.Exists(file)) return false;

        WriteLog("发现更新包 {0}", file);

        // 解压更新程序包
        if (!file.EndsWithIgnoreCase(".zip", ".7z")) return false;

        var tmp = Path.GetTempPath().CombinePath(Path.GetFileNameWithoutExtension(file));
        WriteLog("解压缩更新包到临时目录 {0}", tmp);
        file.AsFile().Extract(tmp, true);

        // 拷贝替换更新
        CopyAndReplace(tmp, DestinationPath);

        //// 删除备份文件
        //DeleteBackup(DestinationPath);
        //!!! 先别急着删除，在Linux上，删除正在使用的文件可能导致进程崩溃

        WriteLog("更新成功！");

        return true;
    }

    /// <summary>启动当前应用的新进程。当前进程退出</summary>
    public void Run()
    {
        // 启动进程
        var exe = Assembly.GetEntryAssembly()?.Location;
        if (exe.IsNullOrEmpty()) return;

        WriteLog("启动进程 {0}", exe);
        Process.Start(exe);

        WriteLog("退出当前进程");
        if (!Runtime.IsConsole) Process.GetCurrentProcess().CloseMainWindow();
        Environment.Exit(0);
        Process.GetCurrentProcess().Kill();
    }
    #endregion

    #region 辅助
    private HttpClient? _Client;
    private HttpClient CreateClient()
    {
        if (_Client != null) return _Client;

        return _Client = new HttpClient().SetUserAgent();
    }

    ///// <summary>删除备份文件</summary>
    ///// <param name="dest">目标目录</param>
    //[Obsolete("=>DeleteBackup", true)]
    //public static void DeleteBuckup(String dest)
    //{
    //    // 删除备份
    //    var di = dest.AsDirectory();
    //    var fs = di.GetAllFiles("*.del", true);
    //    foreach (var item in fs)
    //    {
    //        try
    //        {
    //            item.Delete();
    //        }
    //        catch { }
    //    }
    //}

    /// <summary>删除备份文件</summary>
    /// <param name="dest">目标目录</param>
    public void DeleteBackup(String dest)
    {
        // 删除备份
        var di = dest.AsDirectory();
        var fs = di.GetAllFiles("*.del", true);
        foreach (var item in fs)
        {
            WriteLog("Delete {0}", item);
            try
            {
                item.Delete();
            }
            catch { }
        }
    }

    /// <summary>
    /// 解压缩
    /// </summary>
    /// <param name="fileName"></param>
    public String Extract(String fileName)
    {
        WriteLog("Extract {0}", fileName);

        var source = Path.GetTempPath().CombinePath(Path.GetFileNameWithoutExtension(fileName));
        WriteLog("解压缩更新包到临时目录 {0}", source);
        fileName.AsFile().Extract(source, true);

        //var source = fileName.TrimEnd(".zip");
        //if (Directory.Exists(source)) Directory.Delete(source, true);
        //source.EnsureDirectory(false);
        //fileName.AsFile().Extract(source, true);

        return source;
    }

    /// <summary>拷贝并替换。正在使用锁定的文件不可删除，但可以改名</summary>
    /// <param name="source">源目录</param>
    /// <param name="dest">目标目录</param>
    public void CopyAndReplace(String source, String dest)
    {
        WriteLog("CopyAndReplace {0} => {1}", source, dest);

        var di = source.AsDirectory();

        // 来源目录根，用于截断
        var root = di.FullName.EnsureEnd(Path.DirectorySeparatorChar.ToString());
        foreach (var item in di.GetAllFiles(null, true))
        {
            var name = item.FullName.TrimStart(root);
            var dst = dest.CombinePath(name).GetBasePath();

            // 如果是应用配置文件，不要更新
            if (dst.EndsWithIgnoreCase(".exe.config") ||
                dst.EqualIgnoreCase("appsettings.json")) continue;

            // 拷贝覆盖
            WriteLog("Copy {0}", name);
            try
            {
                item.CopyTo(dst.EnsureDirectory(true), true);
            }
            catch
            {
                // 如果是exe/dll，则先改名，因为可能无法覆盖
                if (/*dst.EndsWithIgnoreCase(".exe", ".dll") &&*/ File.Exists(dst))
                {
                    //// 先尝试删除
                    //WriteLog("Delete {0}", item);
                    //try
                    //{
                    //    File.Delete(dst);
                    //}
                    //catch
                    //{
                    // 直接Move文件，不要删除，否则Linux上可能导致当前进程退出
                    WriteLog("Move {0}", item);
                    var del = dst + ".del";
                    if (File.Exists(del)) File.Delete(del);
                    File.Move(dst, del);
                    //}

                    item.CopyTo(dst, true);
                }
            }
        }

        // 删除临时目录
        WriteLog("Delete {0}", di.FullName);
        di.Delete(true);
    }
    #endregion

    #region 日志
    /// <summary>日志对象</summary>
    public ILog Log { get; set; } = Logger.Null;

    /// <summary>输出日志</summary>
    /// <param name="format"></param>
    /// <param name="args"></param>
    public void WriteLog(String format, params Object?[] args) => Log?.Info($"[{Name}]{format}", args);
    #endregion
}