YUI.add('io-upload-iframe', function (Y, NAME) {

/**

Extends the IO  to enable file uploads, with HTML forms

using an iframe as the transport medium.

@module io

@submodule io-upload-iframe

@for IO

**/

var w = Y.config.win,

    d = Y.config.doc,

    _std = (d.documentMode && d.documentMode >= 8),

    _d = decodeURIComponent,

    _end = Y.IO.prototype.end;

/**

 * Creates the iframe transported used in file upload

 * transactions, and binds the response event handler.

 *

 * @method _cFrame

 * @private

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

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

 * @param {Object} io

 */

function _cFrame(o, c, io) {

    var i = Y.Node.create('<iframe src="#" id="io_iframe' + o.id + '" name="io_iframe' + 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() { io._uploadComplete(o, c); }, '#io_iframe' + o.id);

}

/**

 * Removes the iframe transport used in the file upload

 * transaction.

 *

 * @method _dFrame

 * @private

 * @param {Number} id The transaction ID used in the iframe's creation.

 */

function _dFrame(id) {

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

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

	Y.log('The iframe transport for transaction ' + id + ' has been destroyed.', 'info', 'io');

}

Y.mix(Y.IO.prototype, {

   /**

    * Parses the POST data object and creates hidden form elements

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

    * @method _addData

    * @private

    * @static

    * @param {Object} f HTML form object.

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

    * @return {Array} o Array of created fields.

    */

    _addData: function(f, s) {

        // Serialize an object into a key-value string using

        // querystring-stringify-simple.

        if (Y.Lang.isObject(s)) {

            s = Y.QueryString.stringify(s);

        }

        var o = [],

            m = s.split('='),

            i, l;

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

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

            o[i].type = 'hidden';

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

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

            f.appendChild(o[i]);

            Y.log('key: ' +  o[i].name + ' and value: ' + o[i].value + ' added as form data.', 'info', 'io');

        }

        return o;

    },

   /**

    * Removes the custom fields created to pass additional POST

    * data, along with the HTML form fields.

    * @method _removeData

    * @private

    * @static

    * @param {Object} f HTML form object.

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

    */

    _removeData: function(f, o) {

        var i, l;

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

            f.removeChild(o[i]);

        }

    },

   /**

    * 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.

    */

    _setAttrs: function(f, id, uri) {

        // Track original HTML form attribute values.

        this._originalFormAttrs = {

            action: f.getAttribute('action'),

            target: f.getAttribute('target')

        };

        f.setAttribute('action', uri);

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

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

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

    },

   /**

    * Reset the HTML form attributes to their original values.

    * @method _resetAttrs

    * @private

    * @static

    * @param {Object} f HTML form object.

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

    */

    _resetAttrs: function(f, a) {

        Y.Object.each(a, function(v, p) {

            if (v) {

                f.setAttribute(p, v);

            }

            else {

                f.removeAttribute(p);

            }

        });

    },

   /**

    * Starts timeout count if the configuration object

    * has a defined timeout property.

    *

    * @method _startUploadTimeout

    * @private

    * @static

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

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

    */

    _startUploadTimeout: function(o, c) {

        var io = this;

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

            function() {

                o.status = 0;

                o.statusText = 'timeout';

                io.complete(o, c);

                io.end(o, c);

                Y.log('Transaction ' + o.id + ' timeout.', 'info', 'io');

            }, c.timeout);

    },

   /**

    * Clears the timeout interval started by _startUploadTimeout().

    * @method _clearUploadTimeout

    * @private

    * @static

    * @param {Number} id - Transaction ID.

    */

    _clearUploadTimeout: function(id) {

        var io = this;

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

        delete io._timeout[id];

    },

   /**

    * Bound to the iframe's Load event and processes

    * the response data.

    * @method _uploadComplete

    * @private

    * @static

    * @param {Object} o The transaction object

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

    */

    _uploadComplete: function(o, c) {

        var io = this,

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

            b = d.one('body'),

            p;

        if (c.timeout) {

            io._clearUploadTimeout(o.id);

        }

		try {

			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.one('pre:first-child');

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

				Y.log('The responseText value for transaction ' + o.id + ' is: ' + o.c.responseText + '.', 'info', 'io');

			}

			else {

				o.c.responseXML = d._node;

				Y.log('The response for transaction ' + o.id + ' is an XML document.', 'info', 'io');

			}

		}

		catch (e) {

			o.e = "upload failure";

		}

        io.complete(o, c);

        io.end(o, c);

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

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

        // destroy the iframe.

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

    },

   /**

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

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

    * @method _upload

    * @private

    * @static

    * @param {Object} o The transaction object

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

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

    */

    _upload: function(o, uri, c) {

        var io = this,

            f = (typeof c.form.id === 'string') ? d.getElementById(c.form.id) : c.form.id,

            fields;

        // Initialize the HTML form properties in case they are

        // not defined in the HTML form.

        io._setAttrs(f, o.id, uri);

        if (c.data) {

            fields = io._addData(f, c.data);

        }

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

        // property has been defined.

        if (c.timeout) {

            io._startUploadTimeout(o, c);

            Y.log('Transaction timeout started for transaction ' + o.id + '.', 'info', 'io');

        }

        // Start file upload.

        f.submit();

        io.start(o, c);

        if (c.data) {

            io._removeData(f, fields);

        }

        return {

            id: o.id,

            abort: function() {

                o.status = 0;

                o.statusText = 'abort';

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

                    _dFrame(o.id);

                    io.complete(o, c);

                    io.end(o, c);

                    Y.log('Transaction ' + o.id + ' aborted.', 'info', 'io');

                }

                else {

                    Y.log('Attempted to abort transaction ' + o.id + ' but transaction has completed.', 'warn', 'io');

                    return false;

                }

            },

            isInProgress: function() {

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

            },

            io: io

        };

    },

    upload: function(o, uri, c) {

        _cFrame(o, c, this);

        return this._upload(o, uri, c);

    },

    end: function(transaction, config) {

        var form, io;

        if (config) {

            form = config.form;

            if (form && form.upload) {

                io = this;

                // Restore HTML form attributes to their original values.

                form = (typeof form.id === 'string') ? d.getElementById(form.id) : form.id;

                // Check whether the form still exists before resetting it.

                if (form) {

                    io._resetAttrs(form, this._originalFormAttrs);

                }

            }

        }

        return _end.call(this, transaction, config);

    }

}, true);

}, '@VERSION@', {"requires": ["io-base", "node-base"]});