/*

Copyright (c) 2009, Yahoo! Inc. All rights reserved.

Code licensed under the BSD License:

http://developer.yahoo.net/yui/license.txt

version: 3.0.0

build: 1549

*/

YUI.add('io-xdr', function(Y) {

   /**

    * Extends the IO base class to provide an alternate, Flash transport, for making

    * cross-domain requests.

	* @module io

	* @submodule io-xdr

	*/

   /**

	* @event io:xdrReady

	* @description This event is fired by YUI.io when the specified transport is

	* ready for use.

	* @type Event Custom

	*/

	var E_XDR_READY = 'io:xdrReady',

   /**

	* @description Object that stores callback handlers for cross-domain requests

	* when using Flash as the transport.

	*

	* @property _fn

	* @private

	* @static

	* @type object

	*/

	_fn = {},

   /**

	* @description Map of transaction state used when XDomainRequest is the

	* XDR transport.

	*

	* @property _rS

	* @private

	* @static

	* @type object

	*/

	_rS = {};

   /**

	* @description Method that creates the Flash transport swf.

	*

	* @method _swf

	* @private

	* @static

	* @param {string} uri - location of io.swf.

	* @param {string} yid - YUI instance id.

	* @return void

	*/

	function _swf(uri, yid) {

		var o = '<object id="yuiIoSwf" type="application/x-shockwave-flash" data="' +

		        uri + '" width="0" height="0">' +

		     	'<param name="movie" value="' + uri + '">' +

		     	'<param name="FlashVars" value="yid=' + yid + '">' +

                '<param name="allowScriptAccess" value="always">' +

		    	'</object>',

		    c = document.createElement('div');

		document.body.appendChild(c);

		c.innerHTML = o;

	}

   /**

	* @description Sets event handlers for XDomainRequest transactions.

	*

	* @method _xdr

	* @private

	* @static

    * @param {object} o - Transaction object generated by _create() in io-base.

	* @param {object} c - configuration object for the transaction.

	* @return void

	*/

	function _xdr(o, c) {

		o.c.onprogress = function() { _rS[o.id] = 3; }

		o.c.onload = function() {

			_rS[o.id] = 4;

			Y.io.xdrResponse(o, c, 'success');

		};

		o.c.onerror = function() {

			_rS[o.id] = 4;

			Y.io.xdrResponse(o, c, 'failure');

		};

		if (c.timeout) {

			o.c.ontimeout = function() {

				_rS[o.id] = 4;

				Y.io.xdrResponse(o, c, 'timeout');

			};

			o.c.timeout = c.timeout;

		}

	}

   /**

	* @description Creates a response object for XDR transactions, for success

	* and failure cases.

	*

	* @method _data

	* @private

	* @static

    * @param {object} o - Transaction object generated by _create() in io-base.

	* @param {boolean} isFlash - True if Flash was used as the transport.

	* @param {boolean} isXML - True if the response data are XML.

	*

	* @return object

	*/

	function _data(o, isFlash, isXML) {

		var text, xml;

		if (!o.status) {

			text = isFlash ? decodeURI(o.c.responseText) : o.c.responseText;

			xml = isXML ? Y.DataType.XML.parse(text) : null;

			return { id: o.id, c: { responseText: text, responseXML: xml } };

		}

		else {

			return { id: o.id, status: o.status };

		}

	}

   /**

	* @description Method for intiating an XDR transaction abort.

	*

	* @method _abort

	* @private

	* @static

	* @param {object} o - Transaction object generated by _create() in io-base.

	* @param {object} c - configuration object for the transaction.

	*/

	function _abort(o, c) {

		return c.xdr.use === 'flash' ? o.c.abort(o.id, c) : o.c.abort();

	}

   /**

	* @description Method for determining if an XDR transaction has completed

	* and all data are received.

	*

	* @method _isInProgress.

	* @private

	* @static

	* @param {object} o - Transaction object generated by _create() in io-base.

	* @param {object} c - configuration object for the transaction.

	*/

	function _isInProgress(o, t) {

		return (t === 'flash' && o.c) ? o.c.isInProgress(o.id) : _rS[o.id] !== 4;

	}

    Y.mix(Y.io, {

	   /**

		* @description Map of io transports.

		*

		* @property _transport

		* @private

		* @static

		* @type object

		*/

		_transport: {},

	   /**

	   	* @description Method for accessing the transport's interface for making a

	   	* cross-domain transaction.

	   	*

		* @method _xdr

		* @private

		* @static

		* @param {string} uri - qualified path to transaction resource.

    	* @param {object} o - Transaction object generated by _create() in io-base.

		* @param {object} c - configuration object for the transaction.

		*/

		xdr: function(uri, o, c) {

			if (c.on && c.xdr.use === 'flash') {

				_fn[o.id] = {

					on: c.on,

					context: c.context,

					arguments: c.arguments

				};

				// These nodes do not need to be serialized across Flash's

				// ExternalInterface.  Doing so will result in exceptions.

				c.context = null;

				c.form = null;

				o.c.send(uri, c, o.id);

			}

			else if (window.XDomainRequest) {

				_xdr(o, c);

				o.c.open(c.method || 'GET', uri);

				o.c.send(c.data);

			}

			return {

				id: o.id,

				abort: function() {

					return o.c ? _abort(o, c) : false;

				},

				isInProgress: function() {

					return o.c ? _isInProgress(o, c.xdr.use) : false;

				}

			}

		},

	   /**

	   	* @description Response controller for cross-domain requests when using the

	   	* Flash transport or IE8's XDomainRequest object.

	   	*

		* @method xdrResponse

		* @private

		* @static

    	* @param {object} o - Transaction object generated by _create() in io-base.

		* @param {object} c - configuration object for the transaction.

		* @param {string} e - Event name

		* @return object

		*/

		xdrResponse: function(o, c, e) {

   			var m, fn,

   				isFlash = c.xdr.use === 'flash' ? true : false,

   				isXML = c.xdr.dataType === 'xml' ? true : false;

   				c.on = c.on || {};

   			if (isFlash) {

   				m = _fn || {};

   				fn = m[o.id] ? m[o.id] : null;

   				if (fn) {

	   				c.on = fn.on;

	   				c.context = fn.context;

	   				c.arguments = fn.arguments;

				}

			}

			if (e === ('abort' || 'timeout')) {

				o.status = e;

			}

			switch (e) {

				case 'start':

					Y.io.start(o.id, c);

					break;

				case 'success':

					Y.io.success(_data(o, isFlash, isXML), c);

					isFlash ? delete m[o.id] : delete _rS[o.id];

					break;

				case 'timeout':

				case 'abort':

				case 'failure':

					Y.io.failure(_data(o, isFlash, isXML), c);

					isFlash ? delete m[o.id] : delete _rS[o.id];

					break;

			}

		},

	   /**

		* @description Fires event "io:xdrReady"

		*

		* @method xdrReady

		* @private

		* @static

		* @param {number} id - transaction id

		* @param {object} c - configuration object for the transaction.

		*

		* @return void

		*/

		xdrReady: function(id) {

			Y.fire(E_XDR_READY, id);

		},

	   /**

		* @description Method to initialize the desired transport.

		*

		* @method transport

		* @public

		* @static

		* @param {object} o - object of transport configurations.

		* @return void

		*/

		transport: function(o) {

			var id = o.yid ? o.yid : Y.id;

			_swf(o.src, id);

			this._transport.flash = Y.config.doc.getElementById('yuiIoSwf');

		}

	});

}, '3.0.0' ,{requires:['io-base','datatype-xml']});