function toggleMessage(messageId) {
  toggleClass(messageId, ' closed');
  return false;
}

function toggleClass(id, className) {
  var item = document.getElementById(id);
  if (item != null) {
    var state = item.className.indexOf(className) > -1;
    if (state)
      item.className = item.className.replace(className, '');
    else
      item.className = item.className + className;
  }
}

function copyContent(sourceId, destinationId) {
  var source = document.getElementById(sourceId);
  var destination = document.getElementById(destinationId);
  if (source != null && destination != null)
    destination.innerHTML = source.innerHTML;
}

function showVideo(docID, videoID, autoPlay) {
  toggleClass(currentVideo, ' selected');
  toggleClass('desc'+currentVideo, ' visible');
  currentVideo = docID;
  toggleClass(currentVideo, ' selected');
  toggleClass('desc'+currentVideo, ' visible');
  copyContent('question_'+currentVideo, 'current_question');
  copyContent('answer_'+currentVideo, 'current_answer');
  $.getScript('http://www.tsr.ch/?format=js/get-video-byid&callback=displayStream&vid=' + videoID);
  return false;
}

function displayStream(stream) {
  tsrPlayer.stream = stream;
  if (tsrPlayer.injected)
    tsrPlayer.play();
  else
    tsrPlayer.inject();
}