/* --------------------------------------------------------------
 depending_selects.js 2015-10-15 gm
 Gambio GmbH
 http://www.gambio.de
 Copyright (c) 2015 Gambio GmbH
 Released under the GNU General Public License (Version 2)
 [http://www.gnu.org/licenses/gpl-2.0.html]
 --------------------------------------------------------------
 */

/**
 * Depending Selects Extension
 *
 * Extension that fills other dropdowns with data that relate with the value of the
 * dropdown the listener is bound on.
 *
 * @module Admin/Extensions/depending_selects
 *
 * @deprecated Since JS Engine v1.3
 *
 * @ignore
 */
gx.extensions.module(
    'depending_selects',

    ['form', 'fallback'],

    function (data) {

        'use strict';

        // ------------------------------------------------------------------------
        // VARIABLE DEFINITION
        // ------------------------------------------------------------------------

        var
            /**
             * Extension Reference
             *
             * @type {object}
             */
            $this = $(this),

            /**
             * Default Options
             *
             * @type {object}
             */
            defaults = {
                'cache': false, // Cache requested data, so that an ajax is only called once
                'requestOnInit': true // Update the values on init
            },

            /**
             * Cache Object
             *
             * @type {object}
             */
            cache = {},

            /**
             * Final Options
             *
             * @type {object}
             */
            options = $.extend(true, {}, defaults, data),

            /**
             * Module Object
             *
             * @type {object}
             */
            module = {};

        // ------------------------------------------------------------------------
        // FUNCTIONALITY
        // ------------------------------------------------------------------------

        /**
         * Generate Options
         *
         * Function that generates the option fields for the "other" dropdowns
         *
         * @param {object} dataset Data given by the AJAX-call.
         */
        var _generateOptions = function (dataset) {
            $.each(dataset, function (index, value) {
                var $select = $this.find(index);
                $select.empty();
                jse.libs.form.createOptions($select, value, false, false);
            });
        };

        /**
         * Change Handler
         *
         * Event handler for the change-event on the main dropdown.
         */
        var _changeHandler = function () {
            var $self = $(this),
                $option = $self.children(':selected'),
                dataset = jse.libs.fallback._data($option, 'depending_selects');

            if (cache[dataset.url]) {
                // Use cached data if available
                _generateOptions(cache[dataset.url]);
            } else if (dataset.url) {
                // If an URL is given, request the data via an AJAX-call.
                $.get(dataset.url).done(function (result) {
                    if (result.success) {
                        if (options.cache) {
                            // Cache the data if the option is given
                            cache[dataset.url] = result.data;
                        }
                        _generateOptions(result.data);
                    }
                });
            }
        };

        // ------------------------------------------------------------------------
        // INITIALIZATION
        // ------------------------------------------------------------------------

        /**
         * Initialize function of the extension, called by the engine.
         */
        module.init = function (done) {
            // Display Deprecation Mark
            jse.core.debug.warn('The "depending_selects" extension is deprecated as of v1.3.0, do not use it '
                + 'on new pages.');

            // Bind the change handler on the main dropdown object.
            var $source = $this.find(options.target);
            $source.on('change', _changeHandler);

            // Sets the values of the other dropdowns.
            if (options.requestOnInit) {
                $source.trigger('change', []);
            }

            done();
        };

        // Return data to module engine
        return module;
    });