using ModernWpf.Controls;
using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Threading.Tasks;

namespace EZPPClient_Installer
{
  public class DownloadUtil
  {

    public static async Task<List<string>> FilesToDownload(string pathToEZPP, bool reinstall)
    {
      bool directoryExists = Directory.Exists(pathToEZPP);

      List<string> downloadList = new List<string>();
      List<MD5File> md5Files = new List<MD5File>();

      try
      {
        using (WebClient wc = new WebClient())
        {
          wc.Headers.Add("user-agent", "EZPPClientInstaller");
          var data = await wc.DownloadStringTaskAsync("https://new.ez-pp.farm/ezppclient?list&release=" + MainWindow.RELEASESTREAM.ToLower());
          string[] dataList = data.Split('\n');
          foreach (string datastring in dataList)
          {
            if (string.IsNullOrWhiteSpace(datastring) || !datastring.Contains("#"))
              continue;
            
            string[] se = datastring.Split('#');
            string md5 = StripHTML(se[0]);
            string name = StripHTML(se[1]);
            md5Files.Add(new MD5File(name, md5));
          }
        }
      }
      catch (WebException error)
      {
        _ = new ContentDialog()
        {
          Title = "Oops...",
          Content = "A error occurred while trying to fetch all needed Files.\n" + error.Message,
          PrimaryButtonText = "Okay"
        }.ShowAsync();
      }

      if (!directoryExists || reinstall)
      {
#if DEBUG
        MessageBox.Show("Folder does not exist: " + pathToEZPP);
#endif
        foreach (MD5File md5File in md5Files)
          downloadList.Add(md5File.Name);
      }
      else
      {
        foreach (MD5File md5file in md5Files)
        {
          string file = pathToEZPP + @"\" + md5file.Name;
          bool doesExistOnPC = File.Exists(file);
          if (!doesExistOnPC)
          {
            downloadList.Add(md5file.Name);
          }
          else
          {
            string onlineHash = md5file.MD5;
            string pcHash = MD5Util.CalculateMD5(file);
#if DEBUG
            MessageBox.Show("Filename: " + md5file.Name + "\nOnline-Hash: " + onlineHash + "\n PC-Hash: " + pcHash);
#endif
            if (!string.Equals(onlineHash, pcHash))
            {
              downloadList.Add(md5file.Name);
            }
          }
        }
      }

#if DEBUG
      MessageBox.Show(downloadList.Count + "/" + md5Files.Count + " Files need for update");
#endif
      return downloadList;
    }

    public static async Task DownloadFiles(List<string> files, string path)
    {
      if (!Directory.Exists(path))
        Directory.CreateDirectory(path);

      foreach (string file in files)
        if (File.Exists(path + @"\" + file))
          File.Delete(path + @"\" + file);

      foreach (string filename in files)
      {
        await DownloadFile(filename, path);

      }
    }



    private static async Task DownloadFile(string filename, string path)
    {

      long last = -1;
      long lastTransferRate = -1;

      List<long> byteTransfer = new List<long>();

      try
      {
        using (WebClient wc = new WebClient())
        {
          wc.Headers.Add("user-agent", "EZPPClientInstaller");
          wc.DownloadProgressChanged += (sender, value) =>
          {

            var bytesReceived = value.BytesReceived;
            var totalBytes = value.TotalBytesToReceive;
            var currentMillis = DateTimeOffset.Now.ToUnixTimeMilliseconds();
            var diffMillis = Math.Abs(currentMillis - last);
            if (diffMillis >= 1000 || last == -1)
            {
              if (lastTransferRate != -1)
              {
                long transfer = Math.Abs(lastTransferRate - bytesReceived);
                byteTransfer.Add(transfer);
                if (byteTransfer.Count > 5)
                  byteTransfer.RemoveAt(0);
              }
              lastTransferRate = bytesReceived;
              last = DateTimeOffset.Now.ToUnixTimeMilliseconds();
            }

            long averageTransferRate = 0;
            if (byteTransfer.Count > 0)
            {
              foreach (long tr in byteTransfer)
              {
                averageTransferRate += tr;
              }
              averageTransferRate /= byteTransfer.Count;
            }

            MainWindow.updateProgress(filename + " - " + value.ProgressPercentage + "% - " + Math.Round((averageTransferRate / 1024000D) * 1.8, 2) + "MBit/s", value.ProgressPercentage);
          };
          await wc.DownloadFileTaskAsync(@"https://new.ez-pp.farm/ezppclient?file=" + filename + "&release=" + MainWindow.RELEASESTREAM.ToLower(), path + @"\" + filename); ;
        }
      }
      catch (WebException)
      {
      }
    }

    private static string StripHTML(string input)
    {
      return input.Replace("\r\n", "").Replace("\r", "").Replace("\n", "");
    }
  }
}