// encapsulate a channel where we do playback

class ShredPlaybackChannel {
  constructor(guildID, vcID, vtID=null, autoJoin=false, active=true) {
    this._guildID = guildID;
    this._vcID = vcID;
    this._vtID = vtID;
    this._uri = ShredPlaybackChannel.defaultURI;
    this._auto = autoJoin;
    this._active = active;
  }

  get guildID()        { return this._guildID; }
  get vcID() { return this._vcID; }
  get vtID() { return this._vtID; }
  get uri() { return this._uri; }
  get autoJoin() { return this.autoJoin === true; }
  get active()   { return this._active === true; }

  stopPlayback(part=false) {
    if(this.voiceConnection) {
      // stop if we are already playing (allows start to reset)
      console.log("Stopping player..");
      this.voiceConnection.stopPlaying();

      if( part !== false ) {
	this.voiceConnection.leave();
      }
    } else {
      console.log("Unable to stop playback: no voice connection.");
    }
  }

  restartPlaybackDelayed(
    // miliseconds of delay before resuming playback
    delay=ShredPlaybackChannel.defaultRestartPlaybackDelayMS
  )
  {
    setTimeout( function() { this.onVoiceConnection() }, delay );
  }

  startPlayback() {
    if(this.voiceConnection) {
      // stop if we are already playing (allows start to reset)
      if(this.voiceConnection.playing) {
	this.stopPlayback();
      }

      // invokes FFMPEG
      this.voiceConnection.play(
	ShredPlaybackChannel.defaultURI,
	ShredPlaybackChannel.defaultStreamOptions
      );

      // if that didn't throw the stream is now active
      this._active = true;

      // auto-reconnect unless stream if stream was active
      this.voiceConnection.once("end", function () {
	if(this.active) {
	  this._active = false;
	  this.restartPlaybackDelayed();
	}
      });
    } else {
      console.log("Unable to start playback: no voice connection.");
    }
  }

  onVoiceConnection(voiceConnection=null) {
    if(voiceConnection) {
      // save new voiceConnection when provided
      this.voiceConnection = voiceConnection;
    }
    if(this.active) {
      this.startPlayback();
    }
  }

  endVoiceConnection() {
    this._active = false;
    if(this.voiceConnection) {
      this.stopPlaying();
      this.voiceConnection = null;
    }
    else {
      console.log(`Cannot end voice connection, no connection to channel ID ${this.vcID}`);
    }
  }

  startVoiceConnection(bot) {
    const me = this;
    bot.joinVoiceChannel( me.vcID ).catch((err) => {
      console.log( 'ERROR: failed to join channel '
		   + `${this.vcID} on guild ${this.guildID}: `
		   + err);
      console.debug( me );
    }).then(function (vc) {
      me.onVoiceConnection(vc);
      if( me.vtID ) {
	bot.createMessage( me.vtID, `Now playing **${me.uri}**`)
      }
    });
  }

  static JoinAndPlay(
    bot,
    guildID,
    voiceChannelID,
    voiceTextChannelID=null,
    autoJoin=false,
    active=true
  )
  {
    try {
      const ch = new ShredPlaybackChannel(
	guildID,
	voiceChannelID,
	voiceTextChannelID,
	autoJoin,
	active
      );
      ch.startVoiceConnection(bot);
      return ch;
    } catch (err) {
      console.log(
	'ERROR: failed to join channel '
	  +`${voiceChannelID} on guild ${guildID}: `
	  + err
      );
    }
  }

  static get defaultURI() { return "https://shred.ing/live.ogg"; }
  static get defaultStreamOptions() { return { voiceDataTimeout: -1 }; }
  static get defaultRestartPlaybackDelayMS() { return 1500; }
}

module.exports = ShredPlaybackChannel;