var sticky = document.getElementsByClassName("sticky")[0];
var startTop;
var navElms = new Array();
const uvod = document.getElementById(introId);
var elements = new Array();
var questionContainers = new Array();                                   
if(exists(uvod)) {
    var table = document.getElementById("myContent");
    addItem(introLabel, introId, table);
    var myId;
    var div;
    var i = 1;
    while((myId = exerciseBaseId + i) && exists(div = document.getElementById(myId))) {
        addItem(exerciseBaseLabel + i, myId, table);
        i++;
    }
    addItem(creditLabel, creditId, table);
    addItems(credit, table);
    addItem(examLabel, examId, table);
    addItems(exam, table);
    addItem(conclusionLabel, conclusionId, table);
} else if(typeof(questionCount) !== "undefined") {
  for(var i = 0; i < questionCount; i++) {
    elements[i] = document.getElementById("q" + (i+1));
  }
  navElms = document.getElementById("myContent").getElementsByTagName("a");
}
if(elements.length > 0) {
  const isTd = navElms[0].nodeName.toLowerCase() == "td";
  startTop = sticky.offsetTop;
  window.onscroll = function(event) {
    var articleTop = document.getElementById("content").offsetTop;
    updateContent();
    var currentValue = getCurrent();
    for(var i = 0; i < elements.length; i++) {
      var topValue = elements[i].offsetTop + articleTop;
      var ind = isTd ? i*2 : i;
      var elm1 = navElms[ind];
      if(currentValue >= topValue && currentValue <= topValue+elements[i].offsetHeight) {
        if (isTd) {
          elm1.style.visibility = "visible";
          navElms[ind+1].setAttribute("class", "bold");
        } else {
          if(elm1.getAttribute("class").indexOf("Bold") == -1) {
            elm1.setAttribute("class", "squareBold");
          }
        }                                                            
      } else {
        if (isTd) {
          elm1.removeAttribute("style");
          navElms[ind+1].removeAttribute("class");
        } else {
          elm1.setAttribute("class", elm1.getAttribute("class").replace("Bold", ""));
        }
      }
    }
  };
      
  window.onresize = updateMenu;
  if(window.onload == null) {
    window.onload = updateMenu;
  } else {
    var txt = window.onload.toString();
    var t = "window.onload = " + txt.substring(0, txt.lastIndexOf("}")) + "  updateMenu()\n}";
    eval(t);
  }
}

function exists(value) {
  return value != null && value !== undefined;
}

function addItem(label, id, element) {
  var itemElement = document.getElementById(id);
  if(exists(itemElement) && exists(label) && exists(id)) {
    elements[elements.length] = itemElement;
    createHrefTr(label, id, element);
  }
}

function addItems(items, element) {
  if(exists(items)) {
    for(var i = 0; i < items.length; i++) {
      addItem(items[i].label, items[i].id, element);
    }
  }
} 

function updateMenu() {
  var sticky = document.getElementsByClassName("sticky")[0];
  var menuToggle = document.getElementById("menu-toggle");
  var siteHeaderMenu = document.getElementById("site-header-menu");
  var destination;
  var value = myGetComputedStyle(menuToggle, "display");
  var height;
  var position;
  var background;
  var menuTop;
  var overflow;
  var menuContentTop;
  var width;
  var windowHeight = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
  if(value == "none") {
    destination = document.getElementsByClassName(exists(uvod) ? "textwidget custom-html-widget" : "widget phpeverywherewidget")[0];
    sticky.removeAttribute("style");
    height = "";
    position = "static";
    background = "";
    menuTop = "";
    overflow = "visible";
    menuContentTop = "";
    width = "";
  } else {
    var page = document.getElementById("page");
    destination = document.getElementById("site-header-menu");
    var pageTop = page.offsetTop;
    menuToggle.style.right = pageTop + "px";
    menuToggle.style.zIndex = "10";
    
    var menuHeght = menuToggle.offsetHeight;
    siteHeaderMenu.style.right = pageTop + "px";
    siteHeaderMenu.style.zIndex = "10";
    sticky.style.display = "block";
    menuContentTop = (pageTop == 0 ? 14 : 0);
    height = (windowHeight - 2*pageTop - menuHeght - menuContentTop) + "px";
    position = "fixed";
    background = "white";
    menuTop = menuHeght + "px";
    overflow = "auto";
    width = (page.innerWidth || page.clientWidth) + "px";
    menuContentTop = (-menuContentTop) + "px";
  }
  menuToggle.style.position = position;
  siteHeaderMenu.style.position = position;
  siteHeaderMenu.style.height = height;
  siteHeaderMenu.style.background = background;
  siteHeaderMenu.style.top = menuTop;
  siteHeaderMenu.style.overflow = overflow;
  siteHeaderMenu.style.width = width;
  if(exists(destination)) {
    destination.appendChild(sticky);
  }
  menuToggle.style.top = menuContentTop;
  updateContent();
}

function updateContent() {
  var currentValue = getCurrent();
  if (currentValue > startTop && myGetComputedStyle(document.getElementById("menu-toggle"), "display") == "none") {
      sticky.style.position = 'fixed';
      sticky.style.top = '0px';
      sticky.style.width = document.getElementById("secondary").clientWidth + "px";
  } else {
      sticky.style.position = 'static';
      sticky.style.top = '';
      sticky.style.width = "";
  }
}

function getCurrent() {
  return document.documentElement.scrollTop || window.pageYOffset || window.scrollY;
}

function createHrefTr(text, url, table) {
  var tr = document.createElement("tr");
  var td1 = document.createElement("td");
  var td2 = document.createElement("td");
  td1.setAttribute("class", "td1");
  td1.appendChild(document.createTextNode("►"));
  tr.appendChild(td1);
  navElms[navElms.length] = td1;
  var a = document.createElement("a");
  a.setAttribute("href", "#" + url);
  a.appendChild(document.createTextNode(text));
  td2.appendChild(a);
  tr.appendChild(td2);
  navElms[navElms.length] = td2;
  table.appendChild(tr);
}

function myGetComputedStyle(element, property) {
  var value = null;
  value = eval("getComputedStyle(element, null)." + property + ";");
  return value; 
}

function myClose(element) {
  var parent = element.parentNode.parentNode;
  setCookie("warning", "OFF", 7);
  parent.parentNode.removeChild(parent);  
}

function setCookie(cname, cvalue, exdays) {
  var d = new Date();
  d.setTime(d.getTime() + (exdays*24*60*60*1000));
  var expires = "expires="+ d.toUTCString();
  document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}