/**
 * @requires $ jQuery
 * @requires _ UnderscoreJS
 */
(function(ns) {
    "use strict";
    /**
     * @alias lib.form.element.SelectOther
     * @constructor
     */
    ns.SelectOther = function () { this.construct.apply(this, arguments); };

    var fn = ns.SelectOther.prototype;

    fn.construct = function (options) {
        this.ns = 'feso';
        this.textElement = $('#' + options.id);
        this.selectElement = $('#' + options.selectId);
        this.parentElement = $('#' + options.parentElementId);
        if (!this.textElement.length || !this.selectElement.length) {
            throw Error('SelectOther element initialization failed');
        }
        this.hasOtherInput = options.hasOtherInput;
        this.OTHER = options.OTHER;
        this.selectElement.on('change.' + this.ns, _.bind(this.selectElementOnChange, this));
        if (this.parentElement.length) {
            this.parentElement.on('change.' + this.ns, _.bind(this.parentElementOnChange , this));
            this.queryUrl = options.queryUrl;
        }
    };

    fn.selectElementOnChange = function (event) {
        if (!this.hasOtherInput) {
            this.textElement.val(this.selectElement.val());
            return;
        }
        $('#' + this.textElement.prop('id') + '-element').toggleClass(this.OTHER, this.selectElement.val() == this.OTHER);
        if (this.selectElement.val() == this.OTHER) {
            this.textElement.show();
            if (!event.isTrigger) {
                this.textElement.val('').focus();
            }
        } else {
            this.textElement.val(this.selectElement.val()).hide();
        }
    };

    fn.parentElementOnChange = function (event) {
        if (this.parentElement.val() == '') {
            this.setSelectOptions([]);
        } else {
            var request = {};
            request[this.parentElement.attr('name')] = this.parentElement.val();
            qs.ajax(this.queryUrl, request, {type: 'get'}).done(_.bind(this.onLoadOptions, this));
        }
    };

    fn.setSelectOptions = function (options) {
        var oldValue = this.selectElement.val();
        var otherTitle = this.selectElement.find('option[value="' + this.OTHER + '"]').text();
        var emptyTitle = this.selectElement.find('option[value=""]').text();
        if (this.hasOtherInput) {
            options.push({title: otherTitle, value : this.OTHER});
        }
        qs.form.select.setOptions(this.selectElement.get(0), options, emptyTitle);
        this.selectElement.val(oldValue);
        // Save old value as "other" value when parent element is changed and select element doesn't have such option
        if (this.hasOtherInput && this.selectElement.val() != oldValue) {
            this.selectElement.val(this.OTHER);
            this.textElement.val(oldValue);
        }
        this.selectElement.trigger('change.' + this.ns);
    };

    fn.onLoadOptions = function (options) {
        this.setSelectOptions(options);
    };
})(qs.defineNS('lib.form.element'));