/**
 * This file is public domain.
 * Source: http://www.alistapart.com/articles/alternate/
 * Changes:
 *  2006-10-17, http://daniel.hahler.de/:
 *  - fix/optimization regarding disabling of chosen stylesheet(-set)
 *  - only use selected style from cookie, if available
 *  - Transformed into prototyped object (encapsulation)
 *  - setActiveStyleSheet(): do not disable all stylesheets in case there's
 *    an invalid one provided as param (e.g. from obsolete cookie);
 *    This would disable all styles..!
 *  - Use addEvent() and do not overwrite window.on(un)load
 */

function StyleSwitcher()
{
/**
* Cross browser event handling for IE5+, NS6+ an Mozilla/Gecko
* NOTE: taken/copied here from /rsc/js/functions.js
* @author Scott Andrew
*/
var addEvent = function( elm, evType, fn, useCapture )
{
if( elm.addEventListener )
{ // Standard & Mozilla way:
elm.addEventListener( evType, fn, useCapture );
return true;
}
else if( elm.attachEvent )
{ // IE way:
var r = elm.attachEvent( 'on'+evType, fn );
return r;
}
else
{ // "dirty" way (IE Mac for example):
// Will overwrite any previous handler! :((
elm['on'+evType] = fn;
return false;
}
};

var oThis = this;

this.onload = function(e)
{
var cookie = oThis.readCookie("evo_style");
var title = cookie ? cookie : oThis.getPreferredStyleSheet();
oThis.setActiveStyleSheet(title);
};

addEvent( window, 'load', this.onload, false );

this.onload(); // do it now already, so there's no "skin changing" after load on "larger" pages
};


StyleSwitcher.prototype.setActiveStyleSheet = function (title)
{
var i, a;

var valid = false;

// test if it's a valid one:
for(var i=0; (a = document.getElementsByTagName("link")[i]); i++)
{
if(a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title"))
{
if(a.getAttribute("title") == title)
{
valid = true;
break;
}
}
}

if( ! valid )
return false;

// IE6 and IE7 need to disable all stylesheets first and then re-enable it..
// ..at least when we call the onload event directly, too.
// There is a bug with Konqueror (http://bugs.kde.org/135849) but it does not seem to apply here anymore?!
for(i=0; (a = document.getElementsByTagName("link")[i]); i++)
{
if(a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title"))
{
a.disabled = true;
if(a.getAttribute("title") == title)
{
a.disabled = false;
}
}
}

this.createCookie("evo_style", title, 365);

return true;
};

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

StyleSwitcher.prototype.getPreferredStyleSheet = function()
{
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") )
{
return a.getAttribute("title");
}
}
return null;
};

StyleSwitcher.prototype.createCookie = function(name,value,days)
{
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=/";
};

StyleSwitcher.prototype.readCookie = function(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;
};


var StyleSwitcher = new StyleSwitcher();