/*
  XmlHttpRequest Wrapper
  Version 1.2.2
  29 Jul 2005
  adamv.com/dev/
*/

var Http = {
  ReadyState: {
    Uninitialized: 0,
    Loading: 1,
    Loaded:2,
    Interactive:3,
    Complete: 4
  },

  Status: {
    OK: 200,

    Created: 201,
    Accepted: 202,
    NoContent: 204,

    BadRequest: 400,
    Forbidden: 403,
    NotFound: 404,
    Gone: 410,

    ServerError: 500
  },

  Cache: {
    Get: 1,
    GetCache: 2,
    GetNoCache: 3,
    FromCache: 4
  },

  Method: {Get: "GET", Post: "POST", Put: "PUT", Delete: "DELETE"},

  enabled: false,
  logging: false,
  async: true,
  _get: null, // Reference to the XmlHttpRequest object
  _cache: new Object(),

  Init: function() {
    Http._get = Http._getXmlHttp();
    Http.enabled = (Http._get != null);
    Http.logging = (window.Logging != null);
    Http.async = (window.aSync != null);
  },

  _getXmlHttp: function() {
  /*@cc_on @*//*@if (@_jscript_version >= 5)
    try { return new ActiveXObject("Msxml2.XMLHTTP"); }
    catch (e) {}
    try { return new ActiveXObject("Microsoft.XMLHTTP"); }
    catch (e) {}
  @end @*/
    try { return new XMLHttpRequest();}
    catch (e) {}

    return null;
  },

/*
  Params:
    url: The URL to request. Required.
    cache: Cache control. Defaults to Cache.Get.
    callback: onreadystatechange function, called when request is completed. Optional.
    method: HTTP method. Defaults to Method.Get.
*/
  get: function(params, callback_args) {
    if (!Http.enabled) throw "Http: XmlHttpRequest not available.";

    var url = params.url;
    if (!url) throw "Http: A URL must be specified";

    var cache = params.cache || Http.Cache.Get;
    var method = params.method || Http.Method.Get;
    var callback = params.callback;

    if ((cache == Http.Cache.FromCache) || (cache == Http.Cache.GetCache)) {
      var in_cache = Http.from_cache(url, callback, callback_args);

      if (Http.logging) {
        Logging.log(["Http: URL in cache: " + in_cache]);
      }

      if (in_cache || (cache == Http.Cache.FromCache)) return in_cache;
    }

    if (cache == Http.Cache.GetNoCache) {
      var sep = (-1 < url.indexOf("?")) ? "&" : "?";
      url = url + sep + "__=" + encodeURIComponent((new Date()).getTime());
    }

    // Only one request at a time, please
    if ((Http._get.readyState != Http.ReadyState.Uninitialized) &&
      (Http._get.readyState != Http.ReadyState.Complete)) {
      this._get.abort();

      if (Http.logging) {
        Logging.log(["Http: Aborted request in progress."]);
      }
    }

    Http._get.open(method, url, Http.async);

    Http._get.onreadystatechange =  function() {
      if (Http._get.readyState != Http.ReadyState.Complete) return;

      if (Http.logging) {
        Logging.log(["Http: Returned, status: " + Http._get.status]);
      }

      if ((cache == Http.Cache.GetCache) && (Http._get.status == Http.Status.OK)) {
        Http._cache[url] = Http._get.responseText;
      }

      if (callback_args == null) callback_args = new Array();

      var cb_params = new Array();
      cb_params.push(Http._get);
      for(var i=0;i<callback_args.length;i++)
        cb_params.push(callback_args[i]);

      callback.apply(null, cb_params);
    };

    if(Http.logging) {
      Logging.log(["Http: Started\n\tURL: " + url + "\n\tMethod: " + method + "; Cache: " + Hash.keyName(Http.Cache,cache)]);
    }

    Http._get.send(params.body || null);
  },

  from_cache: function(url, callback, callback_args) {
    var result = Http._cache[url];

    if (result != null) {
      var response = new Http.CachedResponse(result);

      var cb_params = new Array();
      cb_params.push(response);
      for(var i=0;i<callback_args.length;i++)
        cb_params.push(callback_args[i]);

      callback.apply(null, cb_params);

      return true;
    }
    else
      return false;
  },

  clear_cache: function() {
    Http._cache = new Object();
  },

  is_cached: function(url) {
    return Http._cache[url]!=null;
  },

  CachedResponse: function(response) {
    this.readyState = Http.ReadyState.Complete;
    this.status = Http.Status.OK;
    this.responseText = response;
  }
};

Http.Init();

function json_response(response) {
  var js = response.responseText;
  try {
    return eval(js);
  } catch(e) {
    if (Http.logging) {
      Logging.logError(["json_response: " + e]);
    }
    else {
      alert("Error: " + e + "\n" + js);
    }
    return null;
  }
}

function getResponseProps(response, header) {
  try {
    var s = response.getResponseHeader(header || 'X-Ajax-Props');
    if (s==null || s=="")
      return new Object();
    else
      return eval("o="+s);
  } catch (e) {
    return new Object();
  }
}