(function() {
    "use strict";

    angular.module("raz")
        .service("correlationTierService", ["correlationGradeFilterService", "$window", "correlationApiService",
            function (correlationGradeFilterService, $window, correlationApiService) {

                var defaultTierOpen = -1;
                var curTierOpen = null;
                var storageKey = 'ss-Tier-open';
                var curTiers = [];

                function fromStorage() {
                    return $window.sessionStorage.getItem(storageKey);
                }

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

                function getDefaultOpenTier() {
                    return fromStorage() || defaultTierOpen;
                }

                function getOpenTier() {
                    return curTierOpen;
                }

                function setOpenTier(index) {
                    curTierOpen = index;
                    toStorage();
                }

                function setTiers(tiers) {
                    curTiers = tiers;
                }

                setOpenTier(getDefaultOpenTier());

                function getCurTiers() {
                    var selectedGrade = correlationGradeFilterService.getSelectedGrade();
                    if (!curTiers[selectedGrade]) {
                        curTiers[selectedGrade] = [];
                        correlationApiService.getCurTiers(selectedGrade)
                            .then( function (response) { curTiers[selectedGrade] = response; });
                    }
                    return curTiers[selectedGrade];
                }

                function getCurGrade() {
                    return correlationGradeFilterService.getSelectedGrade();
                }

                return {
                    getCurTiers: getCurTiers,
                    getCurGrade: getCurGrade,
                    setOpenTier: setOpenTier,
                    getOpenTier: getOpenTier,
                    setTiers: setTiers
                };

            }]);
})();