/*

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-upload-iframe', function(Y) {

   /**

   	* Extends the IO base class to enable file uploads, with HTML forms,

   	* using an iframe as the transport medium.

	* @module io

	* @submodule io-upload-iframe

	*/

	var w = Y.config.win;

   /**

	* @description Parses the POST data object and creates hidden form elements

	* for each key-value, and appends them to the HTML form object.

	* @method appendData

	* @private

	* @static

	* @param {object} f HTML form object.

	* @param {string} s The key-value POST data.

	* @return {array} e Array of created fields.

	*/

	function _addData(f, s) {

		var o = [],

			m = s.split('='),

			i, l;

		for (i = 0, l = m.length - 1; i < l; i++) {

			o[i] = document.createElement('input');

			o[i].type = 'hidden';

			o[i].name = m[i].substring(m[i].lastIndexOf('&') + 1);

			o[i].value = (i + 1 === l) ? m[i + 1] : m[i + 1].substring(0, (m[i + 1].lastIndexOf('&')));

			f.appendChild(o[i]);

		}

		return o;

	}

   /**

	* @description Removes the custom fields created to pass additional POST

	* data, along with the HTML form fields.

	* @method f

	* @private

	* @static

	* @param {object} f HTML form object.

	* @param {object} o HTML form fields created from configuration.data.

	* @return {void}

	*/

	function _removeData(f, o) {

		var i, l;

		for(i = 0, l = o.length; i < l; i++){

			f.removeChild(o[i]);

		}

	}

   /**

	* @description Sets the appropriate attributes and values to the HTML

	* form, in preparation of a file upload transaction.

	* @method _setAttrs

	* @private

	* @static

	* @param {object} f HTML form object.

	* @param {object} id The Transaction ID.

	* @param {object} uri Qualified path to transaction resource.

	* @return {void}

	*/

	function _setAttrs(f, id, uri) {

		var ie8 = (document.documentMode && document.documentMode === 8) ? true : false;

		f.setAttribute('action', uri);

		f.setAttribute('method', 'POST');

		f.setAttribute('target', 'ioupload' + id );

		f.setAttribute(Y.UA.ie && !ie8 ? 'encoding' : 'enctype', 'multipart/form-data');

	}

   /**

	* @description Sets the appropriate attributes and values to the HTML

	* form, in preparation of a file upload transaction.

	* @method _resetAttrs

	* @private

	* @static

	* @param {object} f HTML form object.

	* @param {object} a Object of original attributes.

	* @return {void}

	*/

	function _resetAttrs(f, a){

		var p;

		for (p in a) {

			if (a.hasOwnProperty(a, p)) {

				if (a[p]) {

					f.setAttribute(p, f[p]);

				}

				else {

					f.removeAttribute(p);

				}

			}

		}

	}

   /**

	* @description Creates the iframe transported used in file upload

	* transactions, and binds the response event handler.

	*

	* @method _create

	* @private

	* @static

    * @param {object} o Transaction object generated by _create().

    * @param {object} c Configuration object passed to YUI.io().

    * @return {void}

	*/

	function _create(o, c) {

		var i = Y.Node.create('<iframe id="ioupload' + o.id + '" name="ioupload' + o.id + '" />');

			i._node.style.position = 'absolute';

			i._node.style.top = '-1000px';

			i._node.style.left = '-1000px';

		Y.one('body').appendChild(i);

		// Bind the onload handler to the iframe to detect the file upload response.

		Y.on("load", function() { _handle(o, c) }, '#ioupload' + o.id);

	}

   /**

	* @description Bound to the iframe's Load event and processes

	* the response data.

	* @method _handle

	* @private

	* @static

	* @param {o} o The transaction object

	* @param {object} c Configuration object for the transaction.

	* @return {void}

	*/

	function _handle(o, c) {

		var d = Y.one('#ioupload' + o.id).get('contentWindow.document'),

			b = d.one('body'),

			xml = (d._node.nodeType === 9),

			p;

		if (c.timeout) {

			_clearTimeout(o.id);

		}

		if (b) {

			// When a response Content-Type of "text/plain" is used, Firefox and Safari

			// will wrap the response string with <pre></pre>.

			p = b.query('pre:first-child');

			o.c.responseText = p ? p.get('innerHTML') : b.get('innerHTML');

		}

		else if (xml) {

			o.c.responseXML =  d._node;

		}

		Y.io.complete(o, c);

		Y.io.end(o, c);

		// The transaction is complete, so call _destroy to remove

		// the event listener bound to the iframe transport, and then

		// destroy the iframe.

		w.setTimeout( function() { _destroy(o.id); }, 0);

	}

   /**

	* @description Starts timeout count if the configuration object

	* has a defined timeout property.

	*

	* @method _startTimeout

	* @private

	* @static

    * @param {object} o Transaction object generated by _create().

    * @param {object} c Configuration object passed to YUI.io().

    * @return {void}

	*/

	function _startTimeout(o, c) {

		Y.io._timeout[o.id] = w.setTimeout(

			function() {

				var r = { id: o.id, status: 'timeout' };

				Y.io.complete(r, c);

				Y.io.end(r, c);

			}, c.timeout);

	}

   /**

	* @description Clears the timeout interval started by _startTimeout().

	* @method _clearTimeout

	* @private

	* @static

    * @param {number} id - Transaction ID.

    * @return {void}

	*/

	function _clearTimeout(id) {

		w.clearTimeout(Y.io._timeout[id]);

		delete Y.io._timeout[id];

	}

   /**

	* @description

	* @method _destroy

	* @private

	* @static

	* @param {o} o The transaction object

	* @param {object} uri Qualified path to transaction resource.

	* @param {object} c Configuration object for the transaction.

	* @return {void}

	*/

	function _destroy(id) {

		Y.Event.purgeElement('#ioupload' + id, false);

		Y.one('body').removeChild(Y.one('#ioupload' + id));

	}

	Y.mix(Y.io, {

	   /**

		* @description Uploads HTML form data, inclusive of files/attachments,

		* using the iframe created in _create to facilitate the transaction.

		* @method _upload

		* @private

		* @static

		* @param {o} o The transaction object

		* @param {object} uri Qualified path to transaction resource.

		* @param {object} c Configuration object for the transaction.

		* @return {void}

		*/

		_upload: function(o, uri, c) {

			var f = (typeof c.form.id === 'string') ? Y.config.doc.getElementById(c.form.id) : c.form.id,

				fields,

				// Track original HTML form attribute values.

				attr = {

					action: f.getAttribute('action'),

					target: f.getAttribute('target')

				};

			_create(o, c);

			// Initialize the HTML form properties in case they are

			// not defined in the HTML form.

			_setAttrs(f, o.id, uri);

			if (c.data) {

				fields = _addData(f, c.data);

			}

			// Start polling if a callback is present and the timeout

			// property has been defined.

			if (c.timeout) {

				_startTimeout(o, c);

			}

			// Start file upload.

			f.submit();

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

			if (c.data) {

				_removeData(f, fields);

			}

			// Restore HTML form attributes to their original values.

			_resetAttrs(f, attr);

			return {

				id: o.id,

				abort: function() {

					var r = { id: o.id, status: 'abort' };

					if (Y.one('#ioupload' + o.id)) {

						_destroy(o.id);

						Y.io.complete(r, c);

						Y.io.end(r, c);

					}

					else {

						return false;

					}

				},

				isInProgress: function() {

					return Y.one('#ioupload' + o.id) ? true : false;

				}

			}

		}

	});

}, '3.0.0' ,{requires:['io-base','node-base','event-base']});