(function () {
  'use strict';

  window.utils = window.utils || {};

  window.utils.stickynav = function (nav) {
    var ticking = false;

    init();
    function init() {
      window.setTimeout(function () {
        nav.classList.add('navbar--animated');
      }, 200);
      checkScroll();
      addListener();
    }

    // checks scroll direction and shows/hides navbar accordingly
    function checkScroll() {
      var sticky = window.scrollY > 0;
      sticky = sticky && window.innerHeight < (document.scrollingElement.scrollHeight - 100);
      nav.classList.toggle('navbar--sticky', sticky);
      ticking = false;
    }

    function addListener() {
      window.addEventListener('scroll', function (e) {
        if (!ticking) {
          window.requestAnimationFrame(checkScroll);
          ticking = true;
        }
      }, false);
    }
  }


})();

document.addEventListener('DOMContentLoaded', function () {

  utils.stickynav(document.querySelector('.js-sticky-navbar'));

});