// ==UserScript==
// @name          Google Groups: Toggle Sidebar
// @namespace     http://loucypher.wordpress.com/
// @include       http://groups.google.com/*
// @description	  foo
// ==/UserScript==

var XPath = '//body/div[@class="topbar"]//td[@align="right"]';
var topbar = document.evaluate(XPath, document, null, 0, null).iterateNext();
if(!topbar) return;

var toggle = document.createElement('a');
toggle.href = top.location.href;
toggle.style.cssFloat = 'left';
toggle.appendChild(document.createTextNode('Sidebar'));
toggle.addEventListener('click',
  function(e) {
    e.preventDefault();
    var nav = document.getElementById('nav');
    var co = document.getElementById('co');
    if(!nav.hasAttribute('style')) {
      nav.style.display = 'none';
      co.style.marginLeft = '0';
      GM_setValue('hideSidebar', true);
    } else {
      nav.removeAttribute('style');
      co.removeAttribute('style');
      GM_setValue('hideSidebar', false);
    }
  },
false);

topbar.insertBefore(toggle, topbar.firstChild);

try {
  var config = GM_getValue('hideSidebar');
} catch(ex) {
  GM_setValue('hideSidebar', false);
};
if(!config) return;
document.getElementById('nav').style.display = 'none';
document.getElementById('co').style.marginLeft = '0';