Emitter.js

var _ = require("underscore"),
  Q = require("q"),
  path = require("path"),
  exec = require("child_process").exec;

module.exports = Emitter;

Emitter.SCRIPT = "build/codesend";

function Emitter(options) {
  this.options = options;
}

/**
 * Send a decimal code through 433Mhz (and return a promise).
 *
 * @param   code        Decimal code
 * @param   [options]   Options to configure pin or pulseLength
 *                      options.pin           Pin on which send the code
 *                      options.pulseLength   Pulse length
 *                      options.protocol      Protocol
 * @param   [callback]  Callback(error, stdout)
 * @return  Promise
 */
Emitter.prototype.sendCode = function(code, options, callback) {
  var deferred = Q.defer();

  //NoOp as default callback
  if (!_.isFunction(callback)) callback = _.noop;

  if (arguments.length === 0 || arguments.length > 3) {
    return deferred.reject(
      new Error("Invalid parameters. sendCode(code, [options, callback])")
    );
  }

  code = parseInt(code);
  if (!_.isNumber(code))
    return deferred.reject(new Error("First parameter must be a integer"));

  //Tidy up
  switch (arguments.length) {
    //function(code)
    case 1:
      options = this.options;
      break;

    //function(code, options || callback)
    case 2:
      //function(code, callback)
      if (_.isFunction(options)) {
        callback = options;
        options = this.options;

        //function(code, options)
      } else if (_.isObject(options)) {
        _.defaults(options, this.options);

        //function(code, ???)
      } else
        return deferred.reject(
          new Error(
            "Second parameter must be a function (callback) or an object (options)"
          )
        );

      break;

    //function(code, options, callback)
    default:
      _.defaults(options, this.options);
      break;
  }

  //Send the code
  exec(
    [
      path.join(__dirname, Emitter.SCRIPT),
      code,
      options.protocol,
      options.pulseLength,
      options.pin
    ].join(" "),
    function(error, stdout, stderr) {
      error = error || stderr;

      if (error) deferred.reject(error);
      else deferred.resolve(stdout);

      callback(error, stdout);
    }
  );

  return deferred.promise;
};