/*
 * $Id: styleswitcher.js 3998 2005-02-15 15:11:32Z scott $
 * Based on Peter Paul Koch's style switcher script:
 * http://www.alistapart.com/articles/alternate/
 */

var cookieName = "theme";
var cookie = readCookie(cookieName);
var title = cookie ? cookie : getPreferredStyleSheet();
setActiveStyleSheet(title);

var previousStyle = null;

function setActiveStyleSheet(title) {
	var currentStyle = getActiveStyleSheet();

	if(currentStyle == title && previousStyle != null)
	{	if(title == previousStyle || !isOptionalStyle(title))
			return;
		else
			title = previousStyle;
	}

	if(previousStyle != currentStyle)
		previousStyle = currentStyle;

	var i, linkElements, a;
  for(i=0, linkElements = document.getElementsByTagName("link"); a = linkElements[i]; i++) {
    if(a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title")) {
      a.disabled = true;
      if(a.getAttribute("title") == title) a.disabled = false;
    }
  }

  if(!isOptionalStyle(title) && navigator.appVersion.indexOf("MISE") != -1)
		location.reload(true);
}

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

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

function createCookie(name,value,days) {
	if(!isOptionalStyle(value))
	{ if (days) {
	    var date = new Date();
	    date.setTime(date.getTime()+(days*24*60*60*1000));
	    var expires = "; expires="+date.toGMTString();
	  }
	  else expires = "";
	  document.cookie = name+"="+value+expires+"; path=/";
	}
}

function readCookie(name) {
  var nameEQ = name + "=";
  var ca = document.cookie.split(';');
  for(var i=0;i < ca.length;i++) {
    var c = ca[i];
    while (c.charAt(0)==' ') c = c.substring(1,c.length);
    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
  }
  return null;
}

function isOptionalStyle(title)
{	title = title.toLowerCase();

	return (title.indexOf("print") != -1 || title.indexOf("image") != -1)
}

window.onload = function(e) {
  var cookie = readCookie(cookieName);
  var title = cookie ? cookie : getPreferredStyleSheet();
  setActiveStyleSheet(title);
}

window.onunload = function(e) {
  var title = getActiveStyleSheet();
  createCookie(cookieName, title, 365);
}