(function (window, document) {
    'use strict';
    const sectionclass = '.kss-section';
    const sectionclasshidden = 'kss-section--hidden';

    let KssSingleSection = function () {
        if (window.location.hash) {
            this.setFocus(window.location.hash.substr(1));
        }
        this.init();
    };

    KssSingleSection.prototype.init = function () {
        let self = this;
        // Initialize toggle button for all sections in navigation.
        let navigationlinks = document.querySelectorAll('.kss-nav__menu-link');
        navigationlinks.forEach(function (links) {
            links.onclick = self.setFocus.bind(self, links.dataset.singlesectiontrigger);
        });
    };

    KssSingleSection.prototype.setFocus = function (id, trigger) {
        let el;
        if (el = document.getElementById(id)) {
            let sections = document.querySelectorAll(sectionclass);
            sections.forEach(function (section) {
                if (section.id === id || section.id.startsWith(id + '-')) {
                    section.classList.remove(sectionclasshidden);
                } else {
                    section.classList.add(sectionclasshidden);
                }
            });
            el.classList.remove(sectionclasshidden);
            this.pushUrl(id);

            if (trigger) {
                let headerHeight = document.querySelector('header.kss-header').offsetHeight;
                let windowTop = document.documentElement.scrollTop;
                let contentTopMargin = windowTop - headerHeight;

                if (windowTop > headerHeight) {
                    el.style.marginTop = contentTopMargin + 'px';
                }
            }
        }

        return true;
    };

    KssSingleSection.prototype.pushUrl = function (id) {
        if (typeof (history.pushState) !== 'undefined') {
            let obj = {
                Url: '#' + id
            };
            history.pushState(null, null, obj.Url);
        } else {
            alert('Browser does not support HTML5.');
        }
    };

    window.KssSingleSection = KssSingleSection;
})(window, document);