using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.IO.Compression;
using System.Net;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace AutoUpdater
{
    public enum DownloadStatus
    {
        Downloading,
        Completed,
        Failed,
        Canceled
    }

    public partial class Downloading : Form
    {
        /// <summary>
        /// 下载器
        /// </summary>
        private FileDownloader downloader;

        /// <summary>
        /// 下载状态
        /// </summary>
        private DownloadStatus status = DownloadStatus.Downloading;

        /// <summary>
        /// 文件总大小
        /// </summary>
        private long totalSize = 0;

        /// <summary>
        /// 最后文件大小
        /// </summary>
        long lastSize = 0;

        /// <summary>
        /// 已经下载文件大小
        /// </summary>
        long completedSize = 0;

        /// <summary>
        /// 是否取消下载
        /// </summary>
        private bool canceled = false;

        /// <summary>
        /// 显示文本长度
        /// </summary>
        const int MAX_URL_LENGTH = 35;

        /// <summary>
        /// 是否更新成功
        /// </summary>
        private bool isUpdateSuccess = false;

        /// <summary>
        /// 执行数据下载
        /// </summary>
        delegate void DownloaderProgress(object sender);

        public Downloading()
        {
            InitializeComponent();

            //按钮切换
            this.btnPause.Tag = "Pause";

            //初始化文件下载
            downloader = new FileDownloader();
        }

        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            //删除下载目录信息
            DeleteFolder(Global.Instance.DownloadPath);

            //版本信息
            this.lblVersion.Text = string.Format(this.lblVersion.Text ,  Global.Instance.NewVersion);

            //remove limits from service point manager
            //ServicePointManager.MaxServicePoints = 10000;
            //ServicePointManager.DefaultConnectionLimit = 10000;
            //ServicePointManager.CheckCertificateRevocationList = true;
            //ServicePointManager.Expect100Continue = false;
            //ServicePointManager.MaxServicePointIdleTime = 1000 * 30;
            //ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;
            //ServicePointManager.UseNagleAlgorithm = false;
            //ServicePointManager.DnsRefreshTimeout = 0;
            ////提升系统外联的最大并发web访问数
            //ServicePointManager.DefaultConnectionLimit = 1024;
            //ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;



            Task.Factory.StartNew(() => { this.DoStartDownload(this); });
        }

        private void DoStartDownload(object sender)
        {
            try
            {
                this.Invoke(new DownloaderProgress(this.downloaderProgress) , new object[] { sender });
                Application.DoEvents();
            }
            catch (InvalidOperationException ex) //不建议使用该方法，目前尚未有效解决
            {
                ExceptionUtils.Current.Handle(ex);
            }
        }

        private void downloaderProgress(object sender)
        {
            try
            {
                DownloadURLCollection urls = Global.Instance.Urls;

                var tasks = new List<Task>();
                foreach (DownloadURL url in urls)
                {
                    tasks.Add(Task.Factory.StartNew<Tuple<bool , long>>(() =>
                    {
                        bool progressKnown = false;
                        long size = DownloadData.GetFileSize(url.URL , out progressKnown);

                        return new Tuple<bool , long>(progressKnown , size);
                    }).ContinueWith((data) =>
                    {
                        Tuple<bool , long> value = data.Result;
                        url.Size = value.Item2;

                        this.totalSize += value.Item2;
                    }));
                }

                Task.WaitAll(tasks.ToArray());

                this.prgOverall.PositionMax = this.totalSize;

                downloader.ProgressChanged += new DownloadProgressHandler(downloader_ProgressChanged);

                long fileSizes = 0;
                foreach (DownloadURL url in urls)
                {
                    if (!canceled)
                    {
                        lastSize = 0;
                        Uri uri = new Uri(url.URL);
                        string fileName = uri.Segments[uri.Segments.Length - 1].ToString();

                        this.prgCurrent.PositionMax = url.Size;

                        if (url.Destination == string.Empty)
                        {
                            url.Destination = FileDownloader.DownloaderTempDirectory;
                        }

                        downloader.Download(url.URL , url.Destination);

                        if (canceled)
                        {
                            break;
                        }
                            

                        fileSizes += url.Size;

                        this.Invoke(new MarshalProgress(MarshaledProgressChanged) , new object[] { null , new DownloadEventArgs(this.totalSize , url.Size) });

                        this.prgOverall.Position = fileSizes;

                        completedSize = fileSizes;
                    }
                }

                this.Invoke(new CompletedDelegate(this.MarshalDownloadComplete));
            }
            catch (Exception ex)
            {
                ExceptionUtils.Current.Handle(ex);
            }
        }

        /// <summary>
        /// 下载处理
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        delegate void MarshalProgress(object sender , DownloadEventArgs e);

        private void downloader_ProgressChanged(object sender , DownloadEventArgs e)
        {
            this.Invoke(new MarshalProgress(this.MarshaledProgressChanged) , new object[] { sender , e });
        }

        string lastPercent = string.Empty;

        private void MarshaledProgressChanged(object sender , DownloadEventArgs e)
        {
            try
            {
                this.prgCurrent.Position = (int)e.CurrentFileSize;
                if (e.CurrentFileSize == this.lastSize)
                {
                    return;
                }

                this.prgOverall.Position += (e.CurrentFileSize - this.lastSize);
                this.completedSize += (e.CurrentFileSize - this.lastSize);
                this.lastSize = e.CurrentFileSize;

                if (e.TotalFileSize > 1024)//以K为单位
                {
                    this.lblCurrentComplete.Text = e.CurrentFileSize / 1024 + "K / " + e.TotalFileSize / 1024 + "K";
                }
                else//小于K
                {
                    this.lblCurrentComplete.Text = e.CurrentFileSize + "B / " + e.TotalFileSize + "B";
                }
                this.prgCurrent.Text = ((int)((((double)e.CurrentFileSize) / e.TotalFileSize) * 100)).ToString() + "%";
                this.prgOverall.Text = ((int)((((double)completedSize) / totalSize) * 100)).ToString() + "%";

                if (this.prgOverall.Text != lastPercent)
                {
                    int index = Text.IndexOf(" (");
                    if (index > -1)
                    {
                        this.Text = this.Text.Substring(0 , index);
                    }

                    this.Text += " (" + this.prgOverall.Text + ")";
                    lastPercent = this.prgOverall.Text;
                }

                Application.DoEvents();
            }
            catch (Exception ex)
            {
                ExceptionUtils.Current.Handle(ex);
            }
        }

        private delegate void CompletedDelegate();
        private void MarshalDownloadComplete()
        {
            if (this.totalSize == this.completedSize)
            {
                this.status = DownloadStatus.Completed;
                //暂停功能无效
                this.btnPause.Visible = false;
                //窗体关闭功能无效

                //关闭按钮无效
                this.btnCancel.Enabled = false;

                //判断主程序是否处于运行状态
                if (this.IsAppInstanceExist(getProcessName()))
                {
                    System.Diagnostics.Process[] startProcesses = System.Diagnostics.Process.GetProcessesByName(getProcessName());
                    foreach (System.Diagnostics.Process start in startProcesses)
                    {
                        start.Kill();
                    }
                }

                //程序延时2秒钟
                System.Threading.Thread.Sleep(1000);

                //将update目录下的 压缩文件 解压
                UnZip(Global.Instance.DownloadPath);

               

                this.canceled = true;

                this.isUpdateSuccess = true;

                if (chkAutoClose.Checked)
                {
                    //升级完成后，启动主程序
                    this.StartApplication(Global.Instance.StartApplication);
                    this.Close();
                }
                else
                {
                    //窗体关闭功能生效

                    //关闭按钮生效
                    this.btnCancel.Enabled = true;
                    this.btnCancel.Text = "关闭";
                }
            }
        }

        /// <summary>
        /// 启动一个应用程序/进程
        /// </summary>
        /// <param name="appFilePath"></param>
        private void StartApplication(string appFilePath)
        {
            string currentPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory , appFilePath);

            if (File.Exists(currentPath))
            {
                Process downprocess = new Process();
                downprocess.StartInfo.FileName = appFilePath;
                downprocess.Start();
            }                
        }

        /// <summary>
        /// 获取进程名称，根据主程序名称
        /// </summary>
        /// <returns></returns>
        private string getProcessName()
        {
            int processIndex = Global.Instance.StartApplication.LastIndexOf(@".");

            string processName = Global.Instance.StartApplication.Substring(0 , processIndex);

            return processName;
        }

        /// <summary>
        /// 监测目标应用程序是否启动
        /// </summary>
        /// <param name="instanceName"></param>
        /// <returns></returns>
        private bool IsAppInstanceExist(string instanceName)
        {
            System.Diagnostics.Process[] startProcesses = System.Diagnostics.Process.GetProcessesByName(instanceName);
            if (startProcesses.Length >= 1)
            {
                return true;
            }
            return false;
        }


        private void btnPause_Click(object sender , System.EventArgs e)
        {
            if (this.btnPause.Tag.ToString() == "Pause")
            {
                downloader.Pause();
                this.btnPause.Text = "继续";
                this.btnPause.Tag = "Resume";
            }
            else if (this.btnPause.Tag.ToString() == "Resume")
            {
                downloader.Resume();
                this.btnPause.Text = "暂停";
                this.btnPause.Tag = "Pause";
            }
        }

        private void btnCancel_Click(object sender , System.EventArgs e)
        {
            if (!canceled)
            {
                downloader.Cancel();
                this.status = DownloadStatus.Canceled;
                this.btnCancel.Text = "关闭";
                this.btnPause.Visible = false;
                //删除下载文件夹
                DeleteFolder(Global.Instance.DownloadPath);
                canceled = true;
            }
            else
            {
                if (isUpdateSuccess)
                {
                    //升级完成后，启动主程序
                    this.StartApplication(Global.Instance.StartApplication);
                }

                this.Close();
            }
        }
        
        /// <summary>
        /// 删除文件夹
        /// </summary>
        /// <param name="dir"></param>
        private void DeleteFolder(string dir)
        {
            if (Directory.Exists(dir))
            {
                foreach (string d in Directory.GetFileSystemEntries(dir))
                {
                    if (File.Exists(d))
                    {
                        FileInfo fi = new FileInfo(d);
                        if (fi.Attributes.ToString().IndexOf("ReadOnly") != -1)
                            fi.Attributes = FileAttributes.Normal;
                        File.Delete(d);//直接删除其中的文件   
                    }
                    else
                        DeleteFolder(d);//递归删除子文件夹   
                }
                Directory.Delete(dir);//删除已空文件夹  
            }
        }

        ////不推荐使用，可能影响其他
        //private void KillProcess()
        //{
        //    Process[] procList = Process.GetProcesses();
        //    for (int i = 0; i < procList.Length; i++)
        //    {
        //        switch (procList[i].ProcessName)
        //        {
        //            case "AutoUpdater":
        //                procList[i].Kill();
        //                procList[i].Close();
        //                break;
        //        }
        //    }
        //}

        private void Downloading_FormClosed(object sender , FormClosedEventArgs e)
        {
            downloader.Cancel();
            this.status = DownloadStatus.Canceled;
            //删除下载文件夹
            DeleteFolder(Global.Instance.DownloadPath);
            canceled = true;

            System.Diagnostics.Process currentProcess = System.Diagnostics.Process.GetCurrentProcess();
            currentProcess.Kill();
        }

        /// <summary>
        /// 复制文件夹所有内容到目标文件夹
        /// </summary>
        /// <param name="srcPath"></param>
        /// <param name="aimPath"></param>
        private void CopyDirectory(string srcPath , string aimPath)
        {
            //检查目标目录是否以目录分割字符结束如果不是则添加之   
            if (aimPath[aimPath.Length - 1] != Path.DirectorySeparatorChar)
                aimPath += Path.DirectorySeparatorChar;
            //判断目标目录是否存在如果不存在则新建之   
            if (!Directory.Exists(aimPath)) Directory.CreateDirectory(aimPath);
            //得到源目录的文件列表，该里面是包含文件以及目录路径的一个数组   
            //如果你指向copy目标文件下面的文件而不包含目录请使用下面的方法   
            //string[]   fileList   =   Directory.GetFiles(srcPath);   
            string[] fileList = Directory.GetFileSystemEntries(srcPath);
            //遍历所有的文件和目录   
            foreach (string file in fileList)
            {
                //先当作目录处理如果存在这个目录就递归Copy该目录下面的文件   
                if (Directory.Exists(file))
                    CopyDirectory(file , aimPath + Path.GetFileName(file));
                //否则直接Copy文件   
                else
                    File.Copy(file , aimPath + Path.GetFileName(file) , true);
            }
        }

        private void UnZip(string srcPath)
        {
            string[] fileList = Directory.GetFiles(srcPath);

            foreach (string file in fileList)
            {
                FileInfo fileInfo = new FileInfo(file);
                if (fileInfo.Extension.ToLower().Equals(".zip"))
                {
                    ZipStorer zip = ZipStorer.Open(file , FileAccess.Read);

                    List<ZipStorer.ZipFileEntry> dir = zip.ReadCentralDir();

                    string path;
                    bool result;

                    foreach (ZipStorer.ZipFileEntry entry in dir)
                    {
                        path = Path.Combine(Application.StartupPath , entry.FilenameInZip);
                        result = zip.ExtractFile(entry , path);
                    }
                    zip.Close();
                    
                    if (fileInfo.Attributes.ToString().IndexOf("ReadOnly") != -1)
                        fileInfo.Attributes = FileAttributes.Normal;
                    File.Delete(file);//直接删除其中的文件   
                }
            }
        }
    }
}