function setActiveStyleSheet(collection,title) {
  var i, a, main;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if(a.getAttribute("rel").indexOf("style") > -1 
      && a.getAttribute("title") && a.getAttribute("title").indexOf(collection) == 0) {
      a.disabled = true;
      if(a.getAttribute("title").indexOf(title) > -1) {
        a.disabled = false;
        if (collection == "font") 
            $('#fontsizechange').text(title);
      }
    }
  }
}

function getActiveStyleSheet(collection) {
  var i, a;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if(a.getAttribute("rel").indexOf("style") > -1 
      && a.getAttribute("title") && a.getAttribute("title").indexOf(collection) == 0 
      && !a.disabled) 
        return a.getAttribute("title").substring(a.getAttribute("title").indexOf("-")+1);
  }
  return null;
}

function getPreferredStyleSheet(collection) {
  var i, a;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if(a.getAttribute("rel").indexOf("style") > -1
       && a.getAttribute("rel").indexOf("alt") == -1
       && a.getAttribute("title") && a.getAttribute("title").indexOf(collection) == 0 
       ) return a.getAttribute("title").substring(a.getAttribute("title").indexOf("-")+1);
  }
  return null;
}

function initialise(suffix) {
    var cookie = $.cookie("style-"+suffix);
    var title = cookie ? cookie : getPreferredStyleSheet(suffix);
    setActiveStyleSheet(suffix,title);
}

function destruct(suffix){
  var title = getActiveStyleSheet(suffix);
  $.cookie("style-"+suffix, title, { expires: 365 });
}

function onChangeLayoutStyle(e){
  if (this.selectedIndex > 0)
    setActiveStyleSheet("layout", this.options[this.selectedIndex].value.toLowerCase());
}

function onClickFontStyle(e){
  e.preventDefault();
  switch (getActiveStyleSheet("font").toLowerCase()) {
    case "larger" : 
      setActiveStyleSheet("font","small");
      break;
    case "large" : 
      setActiveStyleSheet("font","larger");
      break;
    case "medium" :
      setActiveStyleSheet("font","large");
      break;
    case "small" : 
    default :
      setActiveStyleSheet("font","medium");
      break;
  }
}

$(document).ready(function(){
    initialise('layout');
    initialise('font');
    
    $('#pageversionchange').change(onChangeLayoutStyle);
    $('#fontsizechange').click(onClickFontStyle);
});

$(window).unload(function(){
    destruct('layout');
    destruct('font');
});

initialise('layout');
initialise('font');