'use strict';

/**
  Copyright (c) 2011, Sonny Piers <sonny at fastmail dot net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/


var Lightstring = {
  /**
   * @namespace Holds XMPP namespaces.
   * @description http://xmpp.org/xmpp-protocols/protocol-namespaces
   */
  ns: {
    streams: 'http://etherx.jabber.org/streams',
    jabber_client: 'jabber:client',
    xmpp_stanzas: 'urn:ietf:params:xml:ns:xmpp-stanzas'
  },
  /**
   * @namespace Holds XMPP stanza builders.
   */
  stanzas: {
    stream: {
      open: function(aService) {
        return "<stream:stream to='" + aService + "'" +
                             " xmlns='" + Lightstring.ns['jabber_client'] + "'" +
                             " xmlns:stream='" + Lightstring.ns['streams'] + "'" +
                             " version='1.0'>";
      },
      close: function() {
        return "</stream:stream>";
      }
    },
    errors: {
      iq: function(from, id, type, error) {
        return "<iq to='" + from + "'" +
                  " id='" + id + "'" +
                  " type='error'>" +
                 "<error type='" + type + "'>" +
                   "<" + error + " xmlns='" + Lightstring.ns['xmpp_stanzas'] + "'/>" + //TODO: allow text content.
                    //TODO: allow text and payload.
                 "</error>" +
               "</iq>";
      }
    }
  },
  /**
   * @namespace Holds Lightstring plugins
   */
  plugins: {},
  /**
   * @private
   */
  parser: new DOMParser(),
  /**
   * @private
   */
  serializer: new XMLSerializer(),
  /**
   * @function Transforms a XML string to a DOM object.
   * @param {String} aString XML string.
   * @return {Object} Domified XML.
   */
  XML2DOM: function(aString) {
    var DOM = null;
    try {
      DOM = this.parser.parseFromString(aString, 'text/xml').documentElement;
    }
    catch (e) {
      //TODO: error
    }
    finally {
      return DOM;
    };
  },
  /**
   * @function Transforms a DOM object to a XML string.
   * @param {Object} aString DOM object.
   * @return {String} Stringified DOM.
   */
  DOM2XML: function(aElement) {
    var XML = null;
    try {
      XML = this.serializer.serializeToString(aElement);
    }
    catch (e) {
      //TODO: error
    }
    finally {
      return XML;
    };
  },
  /**
   * @function Get an unique identifier.
   * @param {String} [aString] Prefix to put before the identifier.
   * @return {String} Identifier.
   */
  newId: (function() {
    var id = 1024;
    return function(prefix) {
      if (typeof prefix === 'string')
        return prefix + id++;
      return '' + id++;
    };
  })()
};

/**
 * @constructor Creates a new Lightstring connection
 * @param {String} [aService] The Websocket service URL.
 * @memberOf Lightstring
 */
Lightstring.Connection = function(aService) {
  if (aService)
    this.service = aService;
  /**
   * @namespace Holds connection events handlers
   */
  this.handlers = {};
  /**
   * @namespace Holds connection iq callbacks
   */
  this.callbacks = {};
};
Lightstring.Connection.prototype = {
  /**
   * @function Create and open a websocket then go though the XMPP authentification process.
   * @param {String} [aJid] The JID (Jabber id) to use.
   * @param {String} [aPassword] The associated password.
   */
  connect: function(aJid, aPassword) {
    this.emit('connecting');
    this.jid = new Lightstring.JID(aJid);
    if (aPassword)
      this.password = aPassword;

    if (!this.jid.bare)
      return; //TODO: error
    if (!this.service)
      return; //TODO: error

    // Standard
    if (typeof(WebSocket) === 'function')
      this.socket = new WebSocket(this.service, 'xmpp');
    // Safari
    else if (typeof(WebSocket) === 'object')
      this.socket = new WebSocket(this.service, 'xmpp');
    // Old Gecko
    else if (typeof(MozWebSocket) === 'function') {
      this.socket = new MozWebSocket(this.service, 'xmpp');
    }
    // No known WebSocket support
    else {
      return; //TODO: error
    }

    var Conn = this;
    this.socket.addEventListener('open', function() {
      //FIXME: Opera/Safari WebSocket implementation doesn't support sub-protocol mechanism.
      //if (this.protocol !== 'xmpp')
        //return; //TODO: error

      var stream = Lightstring.stanzas.stream.open(Conn.jid.domain);
      this.send(stream);
      var stanza = {
        XML: stream
      };
      Conn.emit('output', stanza);
    });
    this.socket.addEventListener('error', function(e) {
      Conn.emit('disconnecting', e.data);
      //TODO: error
    });
    this.socket.addEventListener('close', function(e) {
      Conn.emit('disconnected', e.data);
    });
    this.socket.addEventListener('message', function(e) {
      var stanza = new Lightstring.Stanza(e.data);

      //FIXME: node-xmpp-bosh sends a self-closing stream:stream tag; it is wrong!
      Conn.emit('input', stanza);

      if (!stanza.DOM)
        return;

      var name = stanza.DOM.localName;

      //Authentication
      //FIXME SASL mechanisms and XMPP features can be both in a stream:features
      if (name === 'features') {
        //SASL mechanisms
        if (stanza.DOM.firstChild.localName === 'mechanisms') {
          stanza.mechanisms = [];
          var nodes = stanza.DOM.getElementsByTagName('mechanism');
          for (var i = 0; i < nodes.length; i++)
            stanza.mechanisms.push(nodes[i].textContent);
          Conn.emit('mechanisms', stanza);
        }
        //XMPP features
        else {
          //TODO: stanza.features
          Conn.emit('features', stanza);
        }
      }
      else if (name === 'challenge') {
        Conn.emit('challenge', stanza);
      }
      else if (name === 'failure') {
        Conn.emit('failure', stanza);
      }
      else if (name === 'success') {
        Conn.emit('success', stanza);
      }

      //Iq callbacks
      else if (name === 'iq') {
        var payload = stanza.DOM.firstChild;
        if (payload)
          Conn.emit('iq/' + payload.namespaceURI + ':' + payload.localName, stanza);

        var id = stanza.DOM.getAttribute('id');
        if (!(id && id in Conn.callbacks))
          return;

        var type = stanza.DOM.getAttribute('type');
        if (type !== 'result' && type !== 'error')
          return; //TODO: warning

        var callback = Conn.callbacks[id];
        if (type === 'result' && callback.success)
          callback.success.call(Conn, stanza);
        else if (type === 'error' && callback.error)
          callback.error.call(Conn, stanza);

        delete Conn.callbacks[id];
      }

      else if (name === 'presence' || name === 'message') {
        Conn.emit(name, stanza);
      }
    });
  },
  /**
   * @function Send a message.
   * @param {String|Object} aStanza The message to send.
   * @param {Function} [aCallback] Executed on answer. (stanza must be iq)
   */
  send: function(aStanza, aSuccess, aError) {
    if (!(aStanza instanceof Lightstring.Stanza))
      var stanza = new Lightstring.Stanza(aStanza);
    else
      var stanza = aStanza;

    if (!stanza)
      return;

    if (stanza.DOM.tagName === 'iq') {
      var type = stanza.DOM.getAttribute('type');
      if (type !== 'get' || type !== 'set')
        ; //TODO: error

      var callback = {success: aSuccess, error: aError};

      var id = stanza.DOM.getAttribute('id');
      if (!id) {
        var id = Lightstring.newId('sendiq:');
        stanza.DOM.setAttribute('id', id);
      }

      this.callbacks[id] = callback;

    }
    else if (aSuccess || aError)
      ; //TODO: warning (no callback without iq)


    //FIXME this.socket.send(stanza.XML); (need some work on Lightstring.Stanza)
    var fixme = Lightstring.DOM2XML(stanza.DOM);
    stanza.XML = fixme;
    this.socket.send(fixme);
    this.emit('output', stanza);
  },
  /**
   * @function Closes the XMPP stream and the socket.
   */
  disconnect: function() {
    this.emit('disconnecting');
    var stream = Lightstring.stanzas.stream.close();
    this.socket.send(stream);
    this.emit('XMLOutput', stream);
    this.socket.close();
  },
  load: function() {
    for (var i = 0; i < arguments.length; i++) {
      var name = arguments[i];
      if (!(name in Lightstring.plugins))
        continue; //TODO: error

      var plugin = Lightstring.plugins[name];

      //Namespaces
      for (var ns in plugin.namespaces)
        Lightstring.ns[ns] = plugin.namespaces[ns];

      //Stanzas
      Lightstring.stanzas[name] = {};
      for (var stanza in plugin.stanzas)
        Lightstring.stanzas[name][stanza] = plugin.stanzas[stanza];

      //Handlers
      for (var handler in plugin.handlers)
        this.on(handler, plugin.handlers[handler]);

      //Methods
      this[name] = {};
      for (var method in plugin.methods)
        this[name][method] = plugin.methods[method].bind(this);

      if (plugin.init)
        plugin.init.apply(this);
    }
  },
  /**
   * @function Emits an event.
   * @param {String} aName The event name.
   * @param {Function|Array|Object} [aData] Data about the event.
   */
  emit: function(aName, aData) {
    var handlers = this.handlers[aName];
    if (!handlers)
      return;

    //Non-data events
    if(!aData) {
      for (var i = 0; i < handlers.length; i++)
        handlers[i].call(this, aData);

      return;
    }

    //Non-iq events
    if (aData && aData.DOM && aData.DOM.localName !== 'iq') {
      for (var i = 0; i < handlers.length; i++)
        handlers[i].call(this, aData);

      return;
    }

    //Iq events
    var ret;
    for (var i = 0; i < handlers.length; i++) {
      ret = handlers[i].call(this, aData);
      if (typeof ret !== 'boolean')
        return; //TODO: error

      if (ret)
        return;
    }

    if (aData && aData.DOM) {
      var type = aData.DOM.getAttribute('type');
      if (type !== 'get' && type !== 'set')
        return;

      var from = aData.DOM.getAttribute('from');
      var id = aData.DOM.getAttribute('id');
      this.send(Lightstring.stanzas.errors.iq(from, id, 'cancel', 'service-unavailable'));
    }
  },
  /**
   * @function Register an event handler.
   * @param {String} aName The event name.
   * @param {Function} aCallback The callback to call when the event is emitted.
   */
  on: function(aName, callback) {
    if (!this.handlers[aName])
      this.handlers[aName] = [];
    this.handlers[aName].push(callback);
  }
};