using System;
using System.Collections.Generic;
using System.IO;
using System.Text;

namespace ChanSort.Api
{
  /// <summary>
  ///   Reads a reference list from a .csv file with the format
  ///   [dummy1],ProgramNr,[dummy2],UID,ChannelName[,SignalSource,FavAndFlags]
  /// </summary>
  public class CsvFileSerializer : SerializerBase
  {
    private static readonly List<string> Columns = new List<string>
    {
      "OldPosition",
      "Position",
      "Name",
      "OriginalNetworkId",
      "TransportStreamId",
      "ServiceId",
      "Favorites",
      "Skip",
      "Lock",
      "Hidden"
    };

    #region ctor()

    public CsvFileSerializer(string fileName) : base(fileName)
    {
      this.Features.ChannelNameEdit = ChannelNameEditMode.All;
      this.Features.CanSkipChannels = true;
      this.Features.CanDeleteChannels = true;
      this.Features.CanHaveGaps = true;
      this.Features.EncryptedFlagEdit = false;
      this.DataRoot.SortedFavorites = false;
      this.DataRoot.SupportedFavorites = Favorites.A | Favorites.B | Favorites.C | Favorites.D | Favorites.E;
    }

    #endregion

    public override string DisplayName => "ChanSort .csv Reference List Loader";

    #region Load()

    public override void Load()
    {
      using (var stream = new StreamReader(this.FileName))
      {
        var lineNr = 0;
        var line = "";
        try
        {
          while ((line = stream.ReadLine()) != null)
            this.ReadChannel(line, ++lineNr);
        }
        catch (Exception ex)
        {
          throw new FileLoadException($"Error in reference file line #{lineNr}: {line}", ex);
        }
      }
    }

    #endregion

    #region ReadChannel()

    private void ReadChannel(string line, int lineNr)
    {
      var parts = CsvFile.Parse(line, ',');
      if (parts.Count < 5) return;
      int programNr;
      if (!int.TryParse(parts[1], out programNr)) return;
      var uid = parts[3];
      if (uid.StartsWith("S")) // remove satellite orbital position from UID ... not all TV models provide this information
        uid = "S" + uid.Substring(uid.IndexOf('-'));
      var signalSource = GetSignalSource(ref programNr, uid, parts);
      if (signalSource == 0)
        return;

      var channelList = this.GetChannelList(signalSource);
      if (channelList == null)
        return;

      var name = parts[4];
      var channel = new ChannelInfo(signalSource, lineNr, programNr, name);

      var uidParts = uid.Split('-');
      if (uidParts.Length >= 4)
      {
        int val;
        if (int.TryParse(uidParts[1], out val))
          channel.OriginalNetworkId = val;
        if (int.TryParse(uidParts[2], out val))
          channel.TransportStreamId = val;
        if (int.TryParse(uidParts[3], out val))
          channel.ServiceId = val;
      }

      if (parts.Count >= 7)
        ApplyFlags(channel, parts[6]);

      this.DataRoot.AddChannel(channelList, channel);
    }

    #endregion

    #region GetSignalSource()

    private static SignalSource GetSignalSource(ref int slot, string uid, IList<string> parts)
    {
      // new lists store a bitmask which defines the type of channel and list it came from
      if (parts.Count >= 6 && parts[5].Length >= 4)
      {
        SignalSource s = 0;
        var code = parts[5];
        if (code[0] == 'A') s |= SignalSource.Analog;
        else if (code[0] == 'D') s |= SignalSource.Digital;

        if (code[1] == 'A') s |= SignalSource.Antenna;
        else if (code[1] == 'C') s |= SignalSource.Cable;
        else if (code[1] == 'S') s |= SignalSource.Sat;
        else if (code[1] == 'I') s |= SignalSource.IP;

        if (code[2] == 'T') s |= SignalSource.Tv;
        else if (code[2] == 'R') s |= SignalSource.Radio;

        s |= (SignalSource) (int.Parse(code.Substring(3)) << 12);
        return s;
      }

      // compatibility for older lists
      var isTv = slot < 0x4000;
      slot &= 0x3FFFF;
      SignalSource signalSource;
      switch (uid[0])
      {
        case 'S':
          signalSource = SignalSource.DvbS;
          break;
        case 'C':
          signalSource = SignalSource.DvbCT;
          break;
        case 'A':
          signalSource = SignalSource.AnalogCT;
          break;
        case 'H':
          signalSource = SignalSource.HdPlusD;
          break;
        default:
          return 0;
      }
      signalSource |= isTv ? SignalSource.Tv : SignalSource.Radio;
      return signalSource;
    }

    #endregion

    #region GetChannelList()

    private ChannelList GetChannelList(SignalSource signalSource)
    {
      var channelList = this.DataRoot.GetChannelList(signalSource);
      if (channelList == null)
      {
        channelList = new ChannelList(signalSource, CreateCaption(signalSource));
        channelList.VisibleColumnFieldNames = Columns;
        this.DataRoot.AddChannelList(channelList);
      }
      return channelList;
    }

    #endregion

    #region CreateCaption()

    private string CreateCaption(SignalSource signalSource)
    {
      var sb = new StringBuilder();
      if ((signalSource & SignalSource.DvbT) == SignalSource.DvbT)
        sb.Append("DVB-T");
      else if ((signalSource & SignalSource.DvbC) == SignalSource.DvbC)
        sb.Append("DVB-C");
      else if ((signalSource & SignalSource.DvbS) == SignalSource.DvbS)
        sb.Append("DVB-S");
      else if ((signalSource & SignalSource.IP) == SignalSource.IP)
        sb.Append("IP");
      else if ((signalSource & SignalSource.Digital) == SignalSource.Digital)
        sb.Append("DVB");
      else if ((signalSource & SignalSource.Analog) == SignalSource.Analog)
        sb.Append("Analog");

      sb.Append(" ");
      if ((signalSource & SignalSource.Tv) == SignalSource.Tv)
        sb.Append("TV");
      else if ((signalSource & SignalSource.Radio) == SignalSource.Radio)
        sb.Append("Radio");
      else
        sb.Append("Data");

      return sb.ToString();
    }

    #endregion

    #region ApplyFlags()

    private void ApplyFlags(ChannelInfo channel, string flags)
    {
      channel.Lock = false;
      channel.Skip = false;
      channel.Hidden = false;

      foreach (var c in flags)
      {
        switch (c)
        {
          case '1':
            channel.Favorites |= Favorites.A;
            break;
          case '2':
            channel.Favorites |= Favorites.B;
            break;
          case '3':
            channel.Favorites |= Favorites.C;
            break;
          case '4':
            channel.Favorites |= Favorites.D;
            break;
          case '5':
            channel.Favorites |= Favorites.E;
            break;
          case 'L':
            channel.Lock = true;
            break;
          case 'S':
            channel.Skip = true;
            break;
          case 'H':
            channel.Hidden = true;
            break;
          case 'D':
            channel.IsDeleted = true;
            break;
        }
      }
    }

    #endregion

    #region EncodeSignalSource()

    private static string EncodeSignalSource(SignalSource signalSource)
    {
      var sb = new StringBuilder();
      if ((signalSource & SignalSource.Analog) != 0) sb.Append('A');
      else sb.Append('D');

      if ((signalSource & SignalSource.Antenna) != 0) sb.Append('A');
      else if ((signalSource & SignalSource.Cable) != 0) sb.Append('C');
      else if ((signalSource & SignalSource.Sat) != 0) sb.Append('S');
      else sb.Append("I");

      if ((signalSource & SignalSource.Radio) != 0) sb.Append('R');
      else sb.Append('T');

      sb.Append((int) signalSource >> 12);
      return sb.ToString();
    }

    #endregion

    #region EncodeFavoritesAndFlags()

    private static string EncodeFavoritesAndFlags(ChannelInfo channel)
    {
      var sb = new StringBuilder();
      if ((channel.Favorites & Favorites.A) != 0) sb.Append('1');
      if ((channel.Favorites & Favorites.B) != 0) sb.Append('2');
      if ((channel.Favorites & Favorites.C) != 0) sb.Append('3');
      if ((channel.Favorites & Favorites.D) != 0) sb.Append('4');
      if ((channel.Favorites & Favorites.E) != 0) sb.Append('5');
      if (channel.Lock) sb.Append('L');
      if (channel.Skip) sb.Append('S');
      if (channel.Hidden) sb.Append('H');
      if (channel.IsDeleted) sb.Append('D');
      return sb.ToString();
    }

    #endregion

    #region Save()

    public override void Save(string tvDataFile)
    {
      Save(tvDataFile, this.DataRoot);
      this.FileName = tvDataFile;
    }

    public static void Save(string tvDataFile, DataRoot dataRoot)
    {
      using (var stream = new StreamWriter(tvDataFile))
      {
        Save(stream, dataRoot);
      }
    }

    public static void Save(StreamWriter stream, DataRoot dataRoot)
    {
      foreach (var channelList in dataRoot.ChannelLists)
      {
        if (channelList.IsMixedSourceFavoritesList) // these pseudo-lists would create dupes for all channels
          continue;

        foreach (var channel in channelList.GetChannelsByNewOrder())
        {
          if (channel.NewProgramNr == -1)
            continue;
          var line = string.Format("{0},{1},{2},{3},\"{4}\",{5},{6}",
            "", // past: channel.RecordIndex,
            channel.NewProgramNr,
            "", // past: channel.TransportStreamId,
            channel.Uid,
            channel.Name,
            EncodeSignalSource(channel.SignalSource),
            EncodeFavoritesAndFlags(channel));
          stream.WriteLine(line);
        }
      }
    }

    #endregion
  }
}