// FADING-CONTENT

var undefined;
var activeID = 'nav1';
var timeFadeIn;
var timeFadeOut;
var running = false;

var idxA = 0;
var idxL = 0;
var arbeitsproben = [];

function lastArbeitsprobe() {
  if (running) {
    return;
  }
  idxL = idxA;
  idxA--;
  if (idxA < 0 ) {
    if (arbeitsproben.length) {
      idxA = arbeitsproben.length - 1;
    } else {
      idxA = 0;
    }
  }
  fadeElements(arbeitsproben[idxA], arbeitsproben[idxL]);
}      

function nextArbeitsprobe() {
  if (running) {
    return;
  }
  idxL = idxA;
  idxA++;
  if (idxA >= arbeitsproben.length ) {
    idxA = 0;
  }
  fadeElements(arbeitsproben[idxA], arbeitsproben[idxL]);
}   

function fadeElements(idxActive, idxLast) {
  var returnFunc = function () {resetThesenText(idxLast)};
   fadeOut(idxLast, 1, returnFunc);
   fadeIn(idxActive, 0);
   cursorFinished();
}

function fadeIn(idx, opac,  returnFunc) {
  if (timeFadeIn) {
    window.clearTimeout(timeFadeIn);
  }
  if (opac == undefined) {
      return;
  }
  var elem = document.getElementById(idx);
  if (! elem) {
    return;
  }
  running = true;
  elem.style.display = 'block';
  var opacGrenzwert = 1;
  if (elem.filters != undefined){
    var opacIE = parseFloat(opac) * 100;
    // IE
    elem.filters['Alpha']['opacity'] = opacIE;
    elem.filters['Alpha']['finishopacity'] = opacIE;
  } else {
    // Other
    elem.style.opacity = opac;
  }
  opac += 0.05;
  if (opac < opacGrenzwert) {
    var func = function () {fadeIn(idx, opac,  returnFunc)};
    timeFadeIn = window.setTimeout(func , 100);
    return;
  }
  elem.className = 'popup-content arbeitsprobe arbeitsprobe-active';
  if (returnFunc) {
    returnFunc();
  }
  running = false;
}    

function fadeOut(idx, opac, returnFunc) {
  if (timeFadeOut) {
    window.clearTimeout(timeFadeOut);
  }
  if (opac == undefined) {
      return;
  }
  var elem = document.getElementById(idx);
  if (! elem) {
    return;
  }
  running = true;
  if (elem.filters != undefined){
    var opacIE = parseFloat(opac) * 100;
    // IE
    elem.filters['Alpha']['opacity'] = opacIE;
    elem.filters['Alpha']['finishopacity'] = opacIE;
  } else {
    // Other
    elem.style.opacity = opac;
  }
  opac -= 0.05;
  if (opac > 0) {
    var func = function () {fadeOut(idx, opac,  returnFunc)};
    timeFadeOut = window.setTimeout(func, 100);
    return;
  }
  elem.style.display = 'none';
  elem.className = 'popup-content arbeitsprobe';
  if (returnFunc) {
    returnFunc();
  }
  running = false;
}

function resetThesenText(idx) {
  var elem = document.getElementById(idx + '-text');
  if (! elem) {
    return;
  }
  elem.style.left = '21px';
  if (document.all) {
    elem.style.left = '35px';
  }
}

function cursorWait() {
  if (! document.getElementsByTagName('body').length){
    return;
  }
  document.getElementsByTagName('body')[0].style.cursor = 'wait';
}

function cursorFinished() {
  if (! document.getElementsByTagName('body').length){
    return;
  }
  document.getElementsByTagName('body')[0].style.cursor = 'auto';
}