(function(){
    "use strict";

    angular.module("raz")
        .service("lcmStandardsCheckboxService", ["$window", function($window){

            var defaultShowStandards = false;
            var showStandards = null;
            var subscribers = [];
            var storageKey = 'lcm-standards-checkbox';

            function fromStorage() {
                var storageVal = $window.sessionStorage.getItem(storageKey);
                if (storageVal !== null) {
                    return storageVal === 'true';
                }
                return null;
            }

            function toStorage() {
                $window.sessionStorage.setItem(storageKey, showStandards);
            }

            function initFromSession() {
                var storageValue = fromStorage();
                if (storageValue !== null) {
                    showStandards = storageValue;
                } else {
                    showStandards = getDefault();
                }
            }

            function getDefault() {
                return defaultShowStandards;
            }

            function toggleShowStandards() {
                showStandards = !showStandards;
                toStorage();
                notifySubscribers();
            }

            function getShowStandards() {
                return showStandards;
            }

            function onUpdate(callback) {
                subscribers.push(callback);
            }

            function notifySubscribers() {
                for (var i = 0; i < subscribers.length; i++) {
                    subscribers[i](showStandards);
                }
            }

            initFromSession();

            return {
                toggleShowStandards: toggleShowStandards,
                getShowStandards: getShowStandards,
                onUpdate: onUpdate
            };

        }]);

})();