(function() {
    'use strict';

    angular.module('shared')
        .service('MenuKeyboardService', function MenuKeyboardService() {
            var service = this;
            var disabled = false;
            var keyboardKeys = {
                enter: 13,
                space: 32,
                down: 40,
                up: 38,
                escape: 27,
                tab: 9,
                home: 36,
                end: 35
            };

            service.keyDown = function(event, clickFunction, hamburgerMenuClassName, popover) {
                if (!disabled) {
                    var chooseFolderElement = $j('.fileCabinetNav-chooseFolder');
                    var lessonPlannerElement = $j('form[name="lesson_plan_form');
                    disabled = (chooseFolderElement != null && chooseFolderElement.length > 0) ||
                        (lessonPlannerElement != null && lessonPlannerElement.length > 0);
                }
                if (disabled) {
                    return;
                }
                switch (event.keyCode) {
                    case keyboardKeys.home: home(event); break;
                    case keyboardKeys.end: end(event); break;
                    case keyboardKeys.tab: tab(event, popover); break;
                    case keyboardKeys.up: arrowUpDown(event,-1,popover); break;
                    case keyboardKeys.down: arrowUpDown(event,1,popover); break;
                    case keyboardKeys.space:
                    case keyboardKeys.enter: spaceOrEnter(event,clickFunction); break;
                    case keyboardKeys.escape: escape(hamburgerMenuClassName,popover); break;
                }
            };

            function home(event) {
                var menuItems = $j('.js-hamburger-menu-item');
                if (menuItems.length > 0) {
                    event.preventDefault();
                    $j(menuItems[0]).focus();
                }
            }

            function end(event) {
                var menuItems = $j('.js-hamburger-menu-item');
                if (menuItems.length > 0) {
                    event.preventDefault();
                    $j(menuItems[menuItems.length - 1]).focus();
                }
            }

            function tab(event, popover) {
                arrowUpDown(event,(event.shiftKey ? -1 : 1), popover);
            }

            function arrowUpDown(event, increment, popover) {
                var menuItems = $j('.js-hamburger-menu-item');
                var htmlElement = event.currentTarget;
                var pos = 0;
                for (pos = 0;pos < menuItems.length;pos++) {
                    if (htmlElement == menuItems[pos]) {
                        break;
                    }
                }
                pos += increment;
                if (pos < 0) {
                    if (event.keyCode == keyboardKeys.tab) {
                        if (popover && popover.popover) {
                            popover.popover.close();
                        }
                        return;
                    }
                    pos = menuItems.length - 1;
                }
                else if (pos > (menuItems.length - 1)) {
                    if (event.keyCode == keyboardKeys.tab) {
                        if (popover && popover.popover) {
                            popover.popover.close();
                        }
                        return;
                    }
                    pos = 0;
                }
                var element = $j(menuItems[pos]);
                if (element != null && element.length > 0) {
                    element.focus();
                    if (element.is(':focus')) {
                        event.preventDefault();
                    }
                }
            }

            function spaceOrEnter(event,clickFunction) {
                if (clickFunction != null) {
                    event.preventDefault();
                    clickFunction();
                }
            }

            function escape(hamburgerMenuClassName,popover) {
                if (popover && popover.popover) {
                    popover.popover.close();
                }
                var element = $j('.' + hamburgerMenuClassName);
                if (element != null && element.length > 0) {
                    element.focus();
                    element.attr('aria-expanded','false');
                }
            }
        });
})();