(function ($) {

        var DropList = function (element, settings, callback) {

                var self = this,
                        doc = $(document),
                        defaults = {
                                direction: 'auto',
                                customScroll: false,
                                namespaces: {
                                        droplist: 'droplist',
                                        clickout: 'droplistClickout'
                                }
                        },

                        /*
                        PRIVATE METHODS
                        ==============================================================================
                        */

                        setText = function (str) {
                                self.option.html(str);
                        },

                        customScroll = function () {

                                var h1 = settings.height || 150,
                                        h2 = self.dropdown.height();

                                if (h2 > h1) {
                                        self.list.css('height', h1 + 'px').jScrollPane({
                                                showArrows: false
                                        });
                                }

                        },

                        layoutController = function () {

                                // config
                                var w = {};
                                w.obj = self.obj.width;
                                w.option = w.obj - self.drop.outerWidth(true) - 7;
                                w.dropdown = w.obj - (self.dropdown.outerWidth(true) - self.dropdown.width());

                                // set
                                self.option.css('width', w.option + 'px');
                                self.dropdown.css('width', w.dropdown + 'px');

                        },

                        options2list = function (data) {

                                var output = '<ul>';
                                data.each(function () {
                                        var selected = $(this).prop('selected') ? 'selected' : '';
                                        output += '<li class="' + selected + '"><a href="' + $(this).val() + '">' + $(this).text() + '</a></li>\t';
                                });
                                output += '</ul>';
                                return output;

                        },

                        setInitialTitle = function () {

                                if (self.obj.title !== '') {
                                        setText(self.obj.title);
                                }

                        },

                        setInitialSelected = function () {

                                var selectedItem = self.list.find('.selected:first');
                                if (selectedItem.length === 1) {
                                        self.set(selectedItem);
                                }
                                else {
                                        self.set(self.list.find('li:first'));
                                }

                        };

                /*
                SETTINGS
                ==============================================================================
                */

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

                /*
                PUBLIC METHODS
                ==============================================================================
                */

                self.open = function () {

                        // just show
                        self.dropdown.show();
                        self.wrapper.addClass('droplist-active');

                        // auto direction
                        if (settings.direction === 'auto') {
                                var distanceFromBottom = (self.select.height() + self.wrapper.offset().top - doc.scrollTop() - $(window).height()) * -1,
                                        objHeight = self.select.height() + self.dropdown.height();
                                if (distanceFromBottom < objHeight) {
                                        self.wrapper.addClass('droplist-up');
                                } else {
                                        self.wrapper.removeClass('droplist-up');
                                }
                        } else if (settings.direction === 'up') {
                                self.wrapper.addClass('droplist-up');
                        }

                        // focus selected item (auto scroll)
                        self.listItems.filter('.selected').focus();

                        // events (clickout / ESC key / type-ahead)
                        self.typedKeys = '';

                        doc.bind('click.' + settings.namespaces.clickout, function (e) {

                                // clickout
                                if ($(e.target).closest('.droplist').length === 0) {
                                        self.close();
                                }

                        }).bind('keyup.' + settings.namespaces.clickout, function (e) {

                                var keycode,
                                        key,
                                        focused,
                                        current,
                                        next;

                                // get keycode
                                if (e === null) { // ie
                                        keycode = event.keyCode;
                                }
                                else { // mozilla
                                        keycode = e.which;
                                }

                                // esc
                                if (keycode === 27) {
                                        self.close();
                                }

                                // space
                                else if (keycode === 32) {

                                        focused = $('a:focus');
                                        current = (focused.parent().is('li')) ? focused.parent() : self.listItems.first();

                                        self.set(current);
                                        self.close();

                                }

                                // type-ahead support
                                else if (keycode >= 0x30 && keycode <= 0x7a) {

                                        // key char
                                        key = String.fromCharCode(keycode);

                                        // clear up
                                        window.clearTimeout(self.typeDelay);

                                        // typing a letter repeatedly
                                        if (self.typedKeys === key) {

                                                current = self.list.find('.selected:first');
                                                next = current.next();
                                                link = next.choldren('a');

                                                if (link.text().toUpperCase().indexOf(self.typedKeys) === 0) {
                                                        self.set(next);
                                                }
                                                else {
                                                        self.setBySearch(self.typedKeys);
                                                }

                                        }

                                        // typing a word
                                        else {

                                                // concatenate
                                                self.typedKeys += key + '';

                                                // wait user to finish typing
                                                self.typeDelay = window.setTimeout(function () {

                                                        self.setBySearch(self.typedKeys);
                                                        self.typedKeys = '';

                                                }, 300);

                                        }

                                }

                        });

                        self.obj.trigger('open.' + settings.namespaces.droplist, self);

                };

                self.close = function () {

                        self.dropdown.hide();
                        self.wrapper.removeClass('droplist-active');
                        doc.unbind('.' + settings.namespaces.clickout);

                        self.obj.trigger('close.' + settings.namespaces.droplist, self);

                };

                self.set = function (el) {

                        var el = $(el),
                                link = el.children('a'),
                                text = link.text();

                        // style
                        self.listItems.removeClass('selected');
                        el.addClass('selected');

                        // text
                        setText(text);

                        // value
                        if (self.originalSelect.length > 0) {
                                var val = el.find('a').attr('href');
                                self.originalSelect.find("option[value$='" + val + "']").prop('selected', true);
                        }

                        // trigger
                        self.obj.trigger('change.' + settings.namespaces.droplist, self);

                };

                self.setBySearch = function (q) {

                        self.listItems.each(function () {
                                var link = $(this).children('a');
                                if (link.text().toUpperCase().indexOf(q) === 0) {
                                        self.set(this);
                                        return false;
                                }
                        });

                };

                self.get = function () {
                        return self.list.find('.selected:first a').attr('href');
                };


                /*
                HELPERS
                ==============================================================================
                */

                self.tabs = function () {

                        var that = this;

                        that.list.find('li').bind('click', function () {
                                that.set(this);
                                that.close();
                                var id = $(this).find('a').attr('href');
                                $(id).removeClass('hide').show().siblings().hide();
                                return false;
                        });

                };


                /*
                CONTROLLER
                ==============================================================================
                */

                self.obj = $(element);
                self.obj.css('border', 'none');

                self.obj.id = self.obj.attr('id');
                self.obj.classname = self.obj.attr('class');
                self.obj.name = self.obj.attr('name');
                self.obj.width = self.obj.width();
                self.obj.title = self.obj.attr('title');

                self.isInsideForm = false;
                self.isDisabled = (self.obj.prop('disabled') == true);

                // style
                if (self.isDisabled) {
                        self.obj.classname += ' droplist-disabled';
                }

                // insert wrapper
                var wrapperHtml = '<div id="' + self.obj.id + '" class="' + self.obj.classname + '"><div class="droplist-list"></div></div>';

                // get elements
                self.wrapper = self.obj.removeAttr('class').wrap(wrapperHtml).parent().parent();
                self.dropdown = self.wrapper.find('.droplist-list:first');
                self.list = self.dropdown.find('ul:first');

                // case it's a SELECT tag, not a UL
                if (self.list.length === 0) {

                        self.isInsideForm = true;

                        var html = '',
                                select = self.dropdown.find('select:first'),
                                optgroups = select.find('optgroup'),
                                options;

                        select.removeAttr('id');

                        if (optgroups.length > 0) {
                                html += '<ul>';
                                optgroups.each(function () {
                                        options = $(this).find('option');
                                        html += '<li><strong>' + $(this).attr('label') + '</strong>' + options2list(options) + '</li>';
                                });
                                html += '</ul>';
                        } else {
                                options = self.dropdown.find('select:first option');
                                html += options2list(options);
                        }

                        self.dropdown.append(html);

                        // override list
                        self.list = self.dropdown.find('ul:first');

                }

                // insert HTML into the wrapper
                self.wrapper.prepend('<div class="droplist-value"><a href="javascript:void(0);"></a><div></div></div>');

                // GET ELEMENTS
                self.listItems = self.list.find('li');
                self.select = self.wrapper.find('.droplist-value:first');
                self.option = self.select.find('div:first');
                self.drop = self.select.find('a:first');
                self.originalSelect = self.wrapper.find('select:first');

                /*
                EVENTS
                ==============================================================================
                */

                if (self.isDisabled == false) {

                        // toggle dropdown
                        self.select.bind('click', function () {
                                if (self.dropdown.is(':hidden')) {
                                        self.open();
                                } else {
                                        self.close();
                                }
                        });

                        if (self.isInsideForm) {

                                // clicking on an option inside a form
                                self.list.find('a').bind('click', function () {
                                        var parent = $(this).parent();
                                        self.set(parent);
                                        self.close();
                                        return false;
                                });

                                // label correlation
                                if (self.obj.id) {
                                        self.wrapper.parents('form').find('label[for="' + self.obj.id + '"]').bind('click', function () {
                                                self.drop.focus();
                                        });
                                }

                        }

                }

                /*
                $(window).bind('resize', function () {
                        layoutController();
                });
                */

                // adjust layout
                layoutController();

                // custom scroll
                if (settings.customScroll) {
                        customScroll();
                }

                // initial state
                setInitialTitle();
                setInitialSelected();
                self.close();

                // callback
                if (typeof callback == 'function') {
                        callback.apply(self);
                }

                return self;

        };


        /*
        INSTANCES MANAGER
        ==============================================================================
        */

        $.fn.droplist = function (settings, callback) {
                return this.each(function () {

                        var obj = $(this),
                                instance = null;

                        if (obj.data('droplist')) return; // return early if this obj already has a plugin instance

                        instance = new DropList(this, settings, callback);
                        obj.data('droplist', instance);

                });
        };

})(jQuery);