freedomjs/freedom

/*jslint indent:2, node:true, sloppy:true */
var util = require('./util');

/**
 * A link connects two freedom hubs. This is an abstract class
 * providing common functionality of translating control channels,
 * and integrating config information.
 * @class Link
 * @implements Port
 * @constructor
 */
var Link = function (name, resource) {
  this.id = 'Link' + Math.random();
  this.name = name;
  this.resource = resource;
  this.config = {};
  this.src = null;

  util.handleEvents(this);
  util.mixin(this, Link.prototype);
};

/**
 * Receive messages from the hub to this port.
 * Manages startup, and passes others to 'deliverMessage' implemented
 * in derived classes.
 * @method onMessage
 * @param {String} flow the channel/flow of the message.
 * @param {Object} message The Message.
 */
Link.prototype.onMessage = function (flow, message) {
  if (flow === 'control' && !this.controlChannel) {
    if (!this.controlChannel && message.channel) {
      this.controlChannel = message.channel;
      util.mixin(this.config, message.config);
      this.start();
    }
  } else {
    this.deliverMessage(flow, message);
  }
};

/**
 * Register a handler to alert of errors on this port.
 * @method addErrorHandler
 * @param {Function} handler Method to call with errors.
 */
Link.prototype.addErrorHandler = function (handler) {
  this.onError = handler;
};

/**
 * Report an error on this link.
 * @method onerror
 * @param {Error} err The error that occurred.
 */
Link.prototype.onError = function (err) {
  //Filled in by addErrorHandler
};

/**
 * Emit messages to the the hub, mapping control channels.
 * @method emitMessage
 * @param {String} flow the flow to emit the message on.
 * @param {Object} messgae The message to emit.
 */
Link.prototype.emitMessage = function (flow, message) {
  if (flow === 'control' && this.controlChannel) {
    flow = this.controlChannel;
  }
  this.emit(flow, message);
};

module.exports = Link;