/**
 * Livejournal userpic adder (v0.2.1)
 *   a script that adds user picks when you hover over a link to a user.
 *
 * CHANGES
 * 2005-08-06 - small fixes (checking to make sure it's GM 0.5 compatible)
 * 2005-06-03 - from loonyone, regular expressions handle user info links
 *
 * TODO
 * ? cache images if firefox isn't already cacheing rss/image requests
 * ? search page for existing icons?
 * ? maybe make it look prettier (border around image?)
 *
 * This file is licensed under the BSD-new license:
 * http://www.opensource.org/licenses/bsd-license.php
 */

// ==UserScript==
// @name      Livejournal userpic adder
// @namespace   http://ponderer.org
// @description   adds user pics of LJ user when you over on a journal link
// @include     http://*.livejournal.com/*
// ==/UserScript==

// these could be combined into a single super regex, but it'd be ugly
var recent_regex = new RegExp("^http://www.livejournal.com/(users|community)/[a-z0-9_]+/?$", "i");
var info_regex = new RegExp("^http://www.livejournal.com/userinfo.bml.user=[a-z0-9_]+$", "i");

function xpath(expr, doc) {
  if (!doc) {
    doc = document;
  }
  var nodes = doc.evaluate(expr, doc, null,
                           XPathResult.ORDERED_NODE_SNAPSHOT_TYPE,
                           null);
  var ret = [];
  for (var n = 0; n < nodes.snapshotLength; ++n) {
    ret.push(nodes.snapshotItem(n));
  }
  return ret;
}


// modified from http://www.quirksmode.org/js/findpos.html
function findPos(obj) {
  var x = 0, y = 0;
  while (obj.offsetParent) {
    x += obj.offsetLeft;
    y += obj.offsetTop;
    obj = obj.offsetParent;
  }
  return [x,y];
}

function mouseover(ev) {
  var pos = findPos(this);
  var div = document.createElement('div');
  div.id = 'usericon_hover';
  div.style.position = 'absolute';
  div.style.left = pos[0] + 'px';
  div.style.top = pos[1] - 8 + 'px';
  
  // make the xmlhttprequest and create the object once it returns
  
  // url of the rss feed
  var url = this.href;
  
  if (url.match(info_regex)) {
    url = url.replace(/^.*=/g, "http://www.livejournal.com/users/")
  }
  
  if (url.charAt(url.length-1) != '/')
    url += '/';
  url += 'data/rss';
  
  this.hovering = true;
  var self = this;
  GM_xmlhttpRequest({
    method: 'GET',
    url: url,
    headers: {'User-Agent': 'usericon greasemonkey script (tony@ponderer.org)'},
    onload: function (res) {
      if (!self.hovering) // cancel request
        return;
      var parser = new DOMParser();
      var dom = parser.parseFromString(res.responseText, "text/xml");

      var nodes = xpath('//image/url/text()', dom);
      for (var n = 0; n < nodes.length; ++n) {
        var url = nodes[n].nodeValue;
        var img = new Image();
        img.onload = function() {
          div.style.top = parseInt(div.style.top) - img.height + 'px';
          div.innerHTML = '<img src="' + url + '"/>';
          document.body.appendChild(div);
        };
        img.src = url;
        return; // found it, time to quit
      }
    },
    data: null
  });
}

function mouseout(ev) {
  // this cancels the request early
  this.hovering = false;
  
  // remove images if they exist
  var elt = document.getElementById('usericon_hover');
  if (elt)
    elt.parentNode.removeChild(elt);
}

var links = document.getElementsByTagName('a');
for (var i = 0; i < links.length; i++) {
  var link = links[i];
  if (link.hasAttribute('href') && 
          (link.href.match(recent_regex) || link.href.match(info_regex))) {
    link.addEventListener('mouseover', mouseover, false);
    link.addEventListener('mouseout', mouseout, false);
  }
}