#define WITH_FAVORITES

using System.Collections.Generic;
using System.Linq;
using Microsoft.Data.Sqlite;
using ChanSort.Api;

namespace ChanSort.Loader.VisionEdge4K
{
  /*
   * This class loads the database.db file from Vision EDGE 4K set-top-boxes.
   * Currently only "satellite_transponder_table" is supported, but there are databases with additional "cable_transponder_table" and "terrestrial_transponder_table" tables.
   * All these transponder tables have tp_id values starting at 0, which makes it unclear how to reference them from within program_table.
   * The guess is that program_table.tp_type=0 means satellite.
   */
  class VisionEdge4KSerializer : SerializerBase
  {
    private readonly ChannelList channels = new (SignalSource.All, "All");
    private readonly ChannelList favs = new (SignalSource.All, "Fav") { IsMixedSourceFavoritesList = true };

    private readonly HashSet<string> tableNames = new();
    private readonly List<int> favListIds = new();
    private readonly Dictionary<int, int> favListIndexById = new();

    #region ctor()
    public VisionEdge4KSerializer(string inputFile) : base(inputFile)
    {
      this.Features.ChannelNameEdit = ChannelNameEditMode.All;
      this.Features.DeleteMode = DeleteMode.Physically;
      this.Features.CanSkipChannels = true;
      this.Features.CanLockChannels = true;
      this.Features.CanHideChannels = true;
#if WITH_FAVORITES
      this.Features.FavoritesMode = FavoritesMode.MixedSource;
#else
      this.Features.FavoritesMode = FavoritesMode.None;
#endif
      this.DataRoot.AddChannelList(this.channels);
      this.DataRoot.AddChannelList(this.favs);
      foreach (var list in this.DataRoot.ChannelLists)
      {
        list.VisibleColumnFieldNames.Remove(nameof(ChannelInfo.AudioPid));
        list.VisibleColumnFieldNames.Remove(nameof(ChannelInfo.ShortName));
        list.VisibleColumnFieldNames.Remove(nameof(ChannelInfo.Provider));
      }
    }
    #endregion

    #region Load()
    public override void Load()
    {
      string connString = $"Data Source={this.FileName};Pooling=False";
      using var conn = new SqliteConnection(connString);
      conn.Open();
      
      using var cmd = conn.CreateCommand();

      this.RepairCorruptedDatabaseImage(cmd);

      cmd.CommandText = "SELECT name FROM sqlite_master WHERE type = 'table'";
      using (var r = cmd.ExecuteReader())
      {
        while (r.Read())
          this.tableNames.Add(r.GetString(0).ToLowerInvariant());
      }

      if (new[] { "satellite_table", "satellite_transponder_table", "program_table", "fav_prog_table"}.Any(tbl => !tableNames.Contains(tbl)))
        throw LoaderException.TryNext("File doesn't contain the expected tables");

      this.ReadSatellites(cmd);
      this.ReadTransponders(cmd);
      this.ReadChannels(cmd);
#if WITH_FAVORITES
      this.ReadFavorites(cmd);
#endif
    }
    #endregion
    
    #region RepairCorruptedDatabaseImage()
    private void RepairCorruptedDatabaseImage(SqliteCommand cmd)
    {
      cmd.CommandText = "REINDEX";
      cmd.ExecuteNonQuery();
    }
    #endregion

    #region ReadSatellites()
    private void ReadSatellites(SqliteCommand cmd)
    {
      cmd.CommandText = "select id, name, angle from satellite_table";
      using var r = cmd.ExecuteReader();
      while (r.Read())
      {
        Satellite sat = new Satellite(r.GetInt32(0));
        string eastWest = "E";
        int pos = r.GetInt32(2);
        // i haven't seen a file containing satellites on the west side. could be either negative or > 180°
        if (pos < 0)
        {
          pos = -pos;
          eastWest = "W";
        }
        else if (pos > 180)
        {
          pos = 360 - pos;
          eastWest = "W";
        }
        sat.OrbitalPosition = $"{pos / 10}.{pos % 10}{eastWest}";
        sat.Name = r.GetString(1);
        this.DataRoot.AddSatellite(sat);
      }
    }
    #endregion

    #region ReadTransponders()
    private void ReadTransponders(SqliteCommand cmd)
    {
      cmd.CommandText = "select id, sat_id, freq, pol, sym_rate from satellite_transponder_table";
      using var r = cmd.ExecuteReader();
      while (r.Read())
      {
        int id = r.GetInt32(0);
        int satId = r.GetInt32(1);
        int freq = r.GetInt32(2);
        
        if (this.DataRoot.Transponder.TryGet(id) != null)
          continue;
        Transponder tp = new Transponder(id);
        tp.FrequencyInMhz = freq;
        tp.Polarity = r.GetInt32(3) == 0 ? 'H' : 'V';
        tp.Satellite = this.DataRoot.Satellites.TryGet(satId);
        tp.SymbolRate = r.GetInt32(4);
        this.DataRoot.AddTransponder(tp.Satellite, tp);
      }
    }
    #endregion

    #region ReadChannels()
    private void ReadChannels(SqliteCommand cmd)
    {
      int ixP = 0;
      int ixST = ixP + 12;

      cmd.CommandText = @"
select 
  p.id, p.disp_order, p.name, p.service_id, p.vid_pid, p.pcr_pid, p.vid_type, p.tv_type, p.ca_type, p.lock, p.skip, p.hide,
  st.sat_id, st.on_id, st.ts_id, st.freq, st.sym_rate
from program_table p
left outer join satellite_transponder_table st on p.tp_type=0 and st.id=p.tp_id";

      using var r = cmd.ExecuteReader();
      while (r.Read())
      {
        var handle = r.GetInt32(ixP + 0);
        var oldProgNr = r.GetInt32(ixP + 1);
        var name = r.GetString(ixP + 2);
        ChannelInfo channel = new ChannelInfo(0, handle, oldProgNr, name);
        channel.ServiceId = r.GetInt32(ixP + 3) & 0x7FFF;
        channel.VideoPid = r.GetInt32(ixP + 4);
        channel.PcrPid = r.GetInt32(ixP + 5);
        var vidType = r.GetInt32(ixP + 6);
        var tvType = r.GetInt32(ixP + 7);
        if (tvType == 0)
        {
          channel.ServiceType = vidType;
          channel.ServiceTypeName = "TV";
          channel.SignalSource |= SignalSource.Tv;
        }
        else
        {
          channel.ServiceType = 0;
          channel.ServiceTypeName = "Radio/Data";
          channel.SignalSource |= SignalSource.Radio | SignalSource.Data;
        }
        channel.Encrypted = r.GetInt32(ixP + 8) != 0;
        channel.Lock = r.GetBoolean(ixP + 9);
        channel.Skip = r.GetBoolean(ixP + 10);
        channel.Hidden = r.GetBoolean(ixP + 11);

        // DVB-S
        if (!r.IsDBNull(ixST + 0))
        {
          var sat = this.DataRoot.Satellites.TryGet(r.GetInt32(ixST + 0));
          channel.Satellite = sat?.Name;
          channel.SatPosition = sat?.OrbitalPosition;
          channel.OriginalNetworkId = r.GetInt32(ixST + 1) & 0x7FFF;
          channel.TransportStreamId = r.GetInt32(ixST + 2) & 0x7FFF;
          channel.FreqInMhz = r.GetInt32(ixST + 3);
          if (channel.FreqInMhz > 20000) // DVB-S is in MHz already, DVB-C/T in kHz
            channel.FreqInMhz /= 1000;
          channel.SymbolRate = r.GetInt32(ixST + 4);
        }

        this.DataRoot.AddChannel(this.channels, channel);
        this.DataRoot.AddChannel(this.favs, channel);
      }
    }
    #endregion

    #region ReadFavorites

    private void ReadFavorites(SqliteCommand cmd)
    {
      cmd.CommandText = "select id, fav_name from fav_name_table";
      using (var r = cmd.ExecuteReader())
      {
        while (r.Read())
        {
          var id = r.GetInt32(0);
          favListIds.Add(id);
          favListIndexById[id] = this.Features.MaxFavoriteLists;
          this.favs.SetFavListCaption(this.Features.MaxFavoriteLists, r.GetString(1));
          ++this.Features.MaxFavoriteLists;
        }
      }

      cmd.CommandText = "select fav_group_id, prog_id, disp_order, tv_type from fav_prog_table";
      using (var r = cmd.ExecuteReader())
      {
        while (r.Read())
        {
          var chan = this.favs.GetChannelById(r.GetInt32(1));
          if (chan == null)
            continue;
          if (!this.favListIndexById.TryGetValue(r.GetInt32(0), out var idx))
            continue;
          chan.SetOldPosition(idx + 1, r.GetInt32(2));
        }
      }
    }
    #endregion


    #region Save()
    public override void Save()
    {
      string channelConnString = $"Data Source={this.FileName};Pooling=False";
      using var conn = new SqliteConnection(channelConnString);
      conn.Open();
      using var trans = conn.BeginTransaction();
      using var cmd = conn.CreateCommand();
      using var cmd2 = conn.CreateCommand();

      this.WriteChannels(cmd, cmd2);
#if WITH_FAVORITES
      this.WriteFavorites(cmd);
#endif
      trans.Commit();

      cmd.Transaction = null;
      this.RepairCorruptedDatabaseImage(cmd);
    }
    #endregion

    #region WriteChannels()
    private void WriteChannels(SqliteCommand cmd, SqliteCommand cmdDelete)
    {
      cmd.CommandText = "update program_table set disp_order=@nr, name=@name, skip=@skip, lock=@lock, hide=@hide where id=@handle";
      cmd.Parameters.Add("@handle", SqliteType.Integer);
      cmd.Parameters.Add("@nr", SqliteType.Integer);
      cmd.Parameters.Add("@name", SqliteType.Text);
      cmd.Parameters.Add("@skip", SqliteType.Integer);
      cmd.Parameters.Add("@lock", SqliteType.Integer);
      cmd.Parameters.Add("@hide", SqliteType.Integer);
      cmd.Prepare();

      cmdDelete.CommandText = "delete from program_table where id=@handle; delete from fav_prog_table where prog_id=@handle;";
      cmdDelete.Parameters.Add("@handle", SqliteType.Integer);
      cmdDelete.Prepare();

      foreach (ChannelInfo channel in this.channels.Channels)
      {
        if (channel.IsProxy) // ignore reference list proxy channels
          continue;

        if (channel.IsDeleted)
        {
          cmdDelete.Parameters["@handle"].Value = channel.RecordIndex;
          cmdDelete.ExecuteNonQuery();
        }
        else
        {
          channel.UpdateRawData();
          cmd.Parameters["@handle"].Value = channel.RecordIndex;
          cmd.Parameters["@nr"].Value = channel.NewProgramNr;
          cmd.Parameters["@name"].Value = channel.Name;
          cmd.Parameters["@skip"].Value = channel.Skip ? 1 : 0;
          cmd.Parameters["@lock"].Value = channel.Lock ? 1 : 0;
          cmd.Parameters["@hide"].Value = channel.Hidden ? 1 : 0;
          cmd.ExecuteNonQuery();
        }
      }
    }
    #endregion

    #region WriteFavorites()
    private void WriteFavorites(SqliteCommand cmd)
    {
      cmd.Parameters.Clear();
      cmd.CommandText = "delete from fav_prog_table";
      cmd.ExecuteNonQuery();

      cmd.CommandText = "insert into fav_prog_table(prog_id, fav_group_id, disp_order, tv_type) values (@progid, @groupid, @order, @type)";
      cmd.Parameters.Add("@progid", SqliteType.Integer);
      cmd.Parameters.Add("@groupid", SqliteType.Integer);
      cmd.Parameters.Add("@order", SqliteType.Integer);
      cmd.Parameters.Add("@type", SqliteType.Integer);

      int max = this.Features.MaxFavoriteLists;
      foreach (var chan in favs.Channels)
      {
        if (chan.IsProxy)
          continue;
        for (int i = 0; i < max; i++)
        {
          var num = chan.GetPosition(i + 1);
          if (num <= 0)
            continue;
          cmd.Parameters["@progid"].Value = chan.RecordIndex;
          cmd.Parameters["@groupid"].Value = this.favListIds[i];
          cmd.Parameters["@order"].Value = num;
          cmd.Parameters["@type"].Value = (chan.SignalSource & SignalSource.Tv) != 0 ? 0 : 1;
          cmd.ExecuteNonQuery();
        }
      }
    }
    #endregion
  }
}