// ==UserScript==
// @name          Show Flickr NSID
// @namespace     http://www.dopiaza.org/flickr/greasemonkey/
// @description   Display user's NSID
// @include       http://www.flickr.com/*
// @include       http://flickr.com/*
// ==/UserScript==

var imgElements = document.getElementsByTagName('img');

var buddyIconPattern = /^http:\/\/static.flickr.com\/\d+\/buddyicons\/(.+).jpg/;
var blockheadPattern = /^http:\/\/www.flickr.com\/images\/buddyicon.jpg\?(.+)$/;

for (var i = 0; i < imgElements.length; i++) 
{
  var img = imgElements[i];

  var imgClass = img.getAttribute('class');
  if (imgClass == 'person_hover_img')
  {
    // Just ignore this one - it's used when you hover over an user's icon
    continue;
  }

  // Check to see if this is a buddy icon image
  var src = img.getAttribute('src');
  var result = buddyIconPattern.exec(src);

  if (result == null)
  {
    // Try the second version, just in case they have no buddy icon set
    result = blockheadPattern.exec(src);
  }

  if (result != null)
  {
    var nsid = result[1];

    // We want the first containing tag that isn't an <a> tag
    var container = img.parentNode;
    while (container.nodeName != null && container.nodeName == 'A')
    {
      container = container.parentNode;
    }

    var node = document.createElement('span');
    node.appendChild(document.createTextNode(nsid));

    node.style.fontSize = 'xx-small';
    node.style.color = 'grey';

    container.appendChild(node);
  }
}