/**
 * socket.io
 * Copyright(c) 2011 LearnBoost <dev@learnboost.com>
 * MIT Licensed
 */

(function (exports) {

  /**
   * Utilities namespace.
   *
   * @namespace
   */

  var util = exports.util = {};

  /**
   * Parses an URI
   *
   * @author Steven Levithan <stevenlevithan.com> (MIT license)
   * @api public
   */

  var re = /^(?:(?![^:@]+:[^:@\/]*@)([^:\/?#.]+):)?(?:\/\/)?((?:(([^:@]*)(?::([^:@]*))?)?@)?([^:\/?#]*)(?::(\d*))?)(((\/(?:[^?#](?![^?#\/]*\.[^?#\/.]+(?:[?#]|$)))*\/?)?([^?#\/]*))(?:\?([^#]*))?(?:#(.*))?)/;

  var parts = ['source', 'protocol', 'authority', 'userInfo', 'user', 'password',
               'host', 'port', 'relative', 'path', 'directory', 'file', 'query',
               'anchor'];

  util.parseUri = function (str) {
    var m = re.exec(str || '')
      , uri = {}
      , i = 14;

    while (i--) {
      uri[parts[i]] = m[i] || '';
    }

    return uri;
  };

  /**
   * Produces a unique url that identifies a Socket.IO connection.
   *
   * @param {Object} uri
   * @api public
   */
  
  util.uniqueUri = function (uri) {
    var protocol = uri.protocol
      , host = uri.host
      , port = uri.port;

    if ('undefined' != typeof document) {
      host = host || document.domain;
      port = port || document.location.port;
    } else {
      host = host || 'localhost';
    }

    return (protocol || 'http') + '://' + host + ':' +
      (port || protocol && protocol === 'https' ? 443 : 80);
  };

  /**
   * Executes the given function when the page is loaded.
   *
   *     io.util.load(function () { console.log('page loaded'); });
   *
   * @param {Function} fn
   * @api public
   */

  var pageLoaded = false;

  util.load = function (fn) {
    if (document.readyState === 'complete' || pageLoaded) {
      return fn();
    }

    util.on(window, 'load', fn, false);
  };

  /**
   * Adds an event.
   *
   * @api private
   */

  util.on = function (element, event, fn, capture) {
    if (element.attachEvent) {
      element.attachEvent('on' + event, fn);
    } else {
      element.addEventListener(event, fn, capture);
    }
  };

  /**
   * Generates the correct `XMLHttpRequest` for regular and cross domain requests.
   *
   * @param {Boolean} [xdomain] Create a request that can be used cross domain.
   * @returns {XMLHttpRequest|false} If we can create a XMLHttpRequest.
   * @api private
   */

  var hasCORS = 'undefined' != typeof window && window.XMLHttpRequest &&
  (function () {
    var a = new XMLHttpRequest();
    return a.withCredentials != undefined;
  })();

  util.request = function (xdomain) {
    if ('undefined' != typeof window) {
      if (xdomain && window.XDomainRequest) {
        return new XDomainRequest();
      };

      if (window.XMLHttpRequest && (!xdomain || hasCORS)) {
        return new XMLHttpRequest();
      };

      if (!xdomain) {
        try {
          return new window.ActiveXObject('Microsoft.XMLHTTP');
        } catch(e) { }
      }
    }

    return null;
  };

  /**
   * XHR based transport constructor.
   *
   * @constructor
   * @api public
   */

  /**
   * Change the internal pageLoaded value.
   */

  if ('undefined' != typeof window) {
    util.load(function () {
      pageLoaded = true;
    });
  }

  /**
   * Defers a function to ensure a spinner is not displayed by the browser
   *
   * @param {Function} fn
   * @api public
   */

  util.defer = function (fn) {
    if (!util.ua.webkit) {
      return fn();
    }

    util.load(function () {
      setTimeout(fn, 100);
    });
  };

  /**
   * Merges two objects.
   *
   * @api public
   */
  
  util.merge = function merge(target, additional, deep, lastseen){
    var seen = lastseen || []
      , depth = typeof deep == 'undefined' ? 2 : deep
      , prop;
    
    for (prop in additional){
      if (additional.hasOwnProperty(prop) && this.indexOf(seen, prop) < 0){
        if (typeof target[prop] !== 'object' || !depth){
          target[prop] = additional[prop];
          seen.push(additional[prop]);
        } else {
          this.merge(target[prop], additional[prop], depth - 1, seen);
        }
      }
    }
    
    return target;
  };
  
  /**
   * Merges prototypes from objects
   *
   * @api public
   */
  
  util.mixin = function (ctor, ctor2) {
    util.merge(ctor.prototype, ctor2.prototype);
  };

  /**
   * Shortcut for prototypical and static inheritance.
   *
   * @api private
   */

  util.inherit = function (ctor, ctor2) {
    ctor.prototype = new ctor2;
    util.merge(ctor, ctor2);
  };

  /**
   * Checks if the given object is an Array.
   *
   *     io.util.isArray([]); // true
   *     io.util.isArray({}); // false
   *
   * @param Object obj
   * @api public
   */

  util.isArray = Array.isArray || function (obj) {
    return Object.prototype.toString.call(obj) === '[object Array]';
  };

  /**
   * Intersects values of two arrays into a third
   *
   * @api public
   */

  util.intersect = function (arr, arr2) {
    var ret = []
      , longest = arr.length > arr2.length ? arr : arr2
      , shortest = arr.length > arr2.length ? arr2 : arr

    for (var i = 0, l = shortest.length; i < l; i++) {
      if (~util.indexOf(longest, shortest[i]))
        ret.push(shortest[i]);
    }

    return ret;
  }

  /**
   * Array indexOf compatibility.
   *
   * @see bit.ly/a5Dxa2
   * @api public
   */
  
  util.indexOf = function (arr, o, i) {
    if (Array.prototype.indexOf) {
      return Array.prototype.indexOf.call(arr, o, i);
    }

    for (var j = arr.length, i = i < 0 ? i + j < 0 ? 0 : i + j : i || 0
        ; i < j && arr[i] !== o; i++);

    return j <= i ? -1 : i;
  };

  /**
   * UA / engines detection namespace.
   *
   * @namespace
   */
  
  util.ua = {};

  /**
   * Detect webkit.
   *
   * @api public
   */

  util.ua.webkit = 'undefined' != typeof navigator
    && /webkit/i.test(navigator.userAgent);

})('undefined' != typeof window ? io : module.exports);