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

(function (exports, global) {

  /**
   * 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 ('document' in global) {
      host = host || document.domain;
      port = port || (protocol == 'https'
        && document.location.protocol !== 'https:' ? 443 : document.location.port);
    } else {
      host = host || 'localhost';

      if (!port && protocol == 'https') {
        port = 443;
      }
    }

    return (protocol || 'http') + '://' + host + ':' + (port || 80);
  };

  /**
   * Mergest 2 query strings in to once unique query string
   *
   * @param {String} base
   * @param {String} addition
   * @api public
   */

  util.query = function (base, addition) {
    var query = util.chunkQuery(base || '')
      , components = [];

    util.merge(query, util.chunkQuery(addition || ''));
    for (var part in query) {
      if (query.hasOwnProperty(part)) {
        components.push(part + '=' + query[part]);
      }
    }

    return components.length ? '?' + components.join('&') : '';
  };

  /**
   * Transforms a querystring in to an object
   *
   * @param {String} qs
   * @api public
   */

  util.chunkQuery = function (qs) {
    var query = {}
      , params = qs.split('&')
      , i = 0
      , l = params.length
      , kv;

    for (; i < l; ++i) {
      kv = params[i].split('=');
      if (kv[0]) {
        query[kv[0]] = kv[1];
      }
    }

    return query;
  };

  /**
   * 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' in global && document.readyState === 'complete' || pageLoaded) {
      return fn();
    }

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

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

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

  util.request = function (xdomain) {
    // if node
    var XMLHttpRequest = require('xmlhttprequest').XMLHttpRequest;
    return new XMLHttpRequest();
    // end node

    if (xdomain && 'undefined' != typeof XDomainRequest) {
      return new XDomainRequest();
    }

    if ('undefined' != typeof XMLHttpRequest && (!xdomain || util.ua.hasCORS)) {
      return new XMLHttpRequest();
    }

    if (!xdomain) {
      try {
        return new 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 || 'undefined' != typeof importScripts) {
      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) && util.indexOf(seen, prop) < 0) {
        if (typeof target[prop] !== 'object' || !depth) {
          target[prop] = additional[prop];
          seen.push(additional[prop]);
        } else {
          util.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) {
    function f() {};
    f.prototype = ctor2.prototype;
    ctor.prototype = new f;
  };

  /**
   * 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) {
    
    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;
  };

  /**
   * Converts enumerables to array.
   *
   * @api public
   */

  util.toArray = function (enu) {
    var arr = [];

    for (var i = 0, l = enu.length; i < l; i++)
      arr.push(enu[i]);

    return arr;
  };

  /**
   * UA / engines detection namespace.
   *
   * @namespace
   */

  util.ua = {};

  /**
   * Whether the UA supports CORS for XHR.
   *
   * @api public
   */

  util.ua.hasCORS = 'undefined' != typeof XMLHttpRequest && (function () {
    try {
      var a = new XMLHttpRequest();
    } catch (e) {
      return false;
    }

    return a.withCredentials != undefined;
  })();

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

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

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