/*
* JUP - plugin for file uploads with JSON support
*
* @name: JUP 
* @author: Khaled Jouda
* @version 1.0.1
* @date 04.08.2009
* @category jQuery plugin 
* @Copyright (c) 2009 Khaled Jouda (doroubna.com)
*
*/
(function($) {
    function JUP(form, settings) {

        var defaults = {
            url: null, /** if not set, form 'action' will be used  */
            validate: null, /** optional function to validate the form */
            beforeUpload: null, /** optional function to call before uploading starts*/
            onComplete: null, /** optional function to call after uploading is completed*/
            json: true /** wether to expect JSON response from upload script or not*/
        };

        var result = null;

        var settings = $.extend({}, defaults, settings);

        if (settings.url != null) {
            form.attr('action', settings.url);
        }

        form.attr("enctype", "multipart/form-data");


        /**
        * @desc submits the form asynchronously
        * 
        */
        form.submit(function(e) {
            /** Do we need to validate the form? */
            if ($.isFunction(settings.validate)) {
                var fields = getFields(form); /** get form fields */
                if (!settings.validate(fields)) {
                    /** not valid */
                    e.preventDefault();
                    return false;
                }
            }

            /** is beforeUpload action set? */
            if ($.isFunction(settings.beforeUpload)) {
                settings.beforeUpload(fields);
            }

            /** Generate the iframe to use*/
            var t = new Date().getTime();
            var iframeId = iframeId = "JUPiFrame" + t;
            var iFrame = $('<iframe id="' + iframeId + '" name="' + iframeId + '" src="javascript:;" style="display:none" />').appendTo(document.body);

            form.attr("target", iframeId);

            form.find("input[type=submit]").attr("disabled", true);


            $("#" + iframeId).load(function() {
                /** form submission is complete,, */

                form.find("input[type=submit]").attr("disabled", false);

                var response = iFrame.contents().find("body").html();

                if ($.isFunction(settings.onComplete)) {

                    if (settings.json) {
                        try {
                            response = eval('(' + response + ')');
                        } catch (e) {
                            response = false;
                        }
                    }

                    settings.onComplete(response, form.attr('id'));

                }

                setTimeout(iFrame.remove, 100); /** why timeout? 
											to prevent firefox from showing 'loading' status forever 
											after iframe removal.. calling 'iframe.remove' inside 'iframe.load' causes this problem 
											*/
            });

        });
        /**
        * @desc gets fields of the form
        * @param form: jquery object of the form
        * @return {array} all fields that have names with their values
        */
        function getFields(form) {
            var fields = {};
            form.find("input,select,textarea").each(function() {
                /** only fields that have names are returned */
                var input = $(this);
                var inputName = input.attr("name");

                if (inputName.length > 1 && inputName.substr(inputName.length - 2, inputName.length) == "[]") {
                    /** input field is an array, example: <input type="checkbox" name="options[]" />  */
                    inputName = inputName.substr(0, inputName.length - 2);
                    if (!fields.hasOwnProperty(inputName)) {
                        fields[inputName] = [];
                    }
                    fields[inputName].push(input.val());
                }
                else if (inputName.length > 0) {
                    fields[inputName] = input.val();
                }
            });
            return fields;
        };
    };

    $.fn.jup = function(settings) {
        return this.each(function() {
            var jup = JUP($(this), settings);
        });
    };
})(jQuery);