const spawn = require('child_process').spawn;

const EventEmitter = require('events').EventEmitter;

const TAGREADER = 'tagreader';
const MP3PLAYER = 'mpg321';

const child_processes = new Map();

function launchChild(name, command) {
  var cmd = command[0],
    args = command.slice(1);

  return spawn(cmd, args);
}

function setupEmitter(name, emitter, child) {
  exports[name] = emitter;

  child.on('error', function(err) {
    emitter.emit('process_error', err);
  });

  child.on('close', function(code, signal) {
    emitter.emit('close', code, signal);
  });

  child.stdout.on('data', (data) => {
    var s = data.toString(), lines = s.split(/\n/g);
    for (var i = 0, l = lines.length; i < l; i++) {
      emitter.emit('message', lines[i]);
    }
  });

  child.stderr.on('data', (data) => {
    emitter.emit('error', data);
  });

  return emitter;
}

exports.init = function(config) {
  // Set up tag reader
  var tagreader = launchChild(TAGREADER, config.tag_reader);
  var tagreader_emitter = new EventEmitter();
  setupEmitter(TAGREADER, tagreader_emitter, tagreader);

  child_processes.set(TAGREADER, tagreader);
  exports.tagreader = tagreader_emitter;

  // set up mp3 player
  var mp3player = launchChild(MP3PLAYER, config.mpg321);
  var mp3player_emitter = new EventEmitter();
  setupEmitter(MP3PLAYER, mp3player_emitter, mp3player);

  child_processes.set(MP3PLAYER, mp3player);
  exports.mp3player = mp3player_emitter;
};

exports.exitHandler = function(options, err) {
  console.log('[player] closing children');
  if (err) console.log(err.stack);

  child_processes.forEach((p) => {
    p.kill();
  });

  if (options.exit) {
    process.exit();
  }
};

// vim:set ts=2 sw=2 et: