// ==UserScript==
// @name        GitHub images as icons
// @description Displays small images in place of file-type icons in a repository source tree
// @namespace   wOxxOm.scripts
// @include     https://github.com/*
// @match       https://github.com/*
// @version     1.01
// @grant       GM_addStyle
// @run-at      document-start
// @downloadURL none
// ==/UserScript==

iconSize = 24;

function addStyle(e) {
  GM_addStyle('.wOxxOm-image-icon { max-width:'+iconSize+'px; max-height:'+iconSize+
              'px; width:auto; height:auto; margin:-4px 0 -7px -6px }');
  window.removeEventListener('DOMContentLoaded', addStyle);
  iconify(document.body);
}
window.addEventListener('DOMContentLoaded', addStyle);

function iconify(n) {
  var aa = (n.className == 'js-directory-link') ? [n] : n.getElementsByClassName('js-directory-link');
  for (var a, i=0; i<aa.length && (a=aa[i++]); ) {
    var r = a.href.match(/github\.com\/(.+?\/)blob\/([^\/]+\/.+?\.(?:png|jpg|jpeg|bmp|gif|cur|ico))$/);
    if (!r)
      continue;

    var td = a.parentNode.parentNode.previousElementSibling;
    if (td.localName != 'td')
      continue;
    
    var icon = td.firstElementChild;
    var img = icon.nextElementSibling;
    if (!img)
      td.insertBefore(img = document.createElement('img'), icon);
    
    icon.style.display = 'none';
    img.className = 'wOxxOm-image-icon';
    img.src = 'https://raw.githubusercontent.com/' + r[1] + r[2];
    td.style.textAlign = 'center';
  }
}

var ob = new MutationObserver(function(mutations){
  for (var m, i=0; i<mutations.length && (m=mutations[i++]) && (mtg=m.target); )
    if (mtg.id == 'js-repo-pjax-container' || (mtg.className == 'files' && mtg.localName == 'table'))
      for (var nn=m.addedNodes, n, j=0; j<nn.length && (n=nn[j++]); )
        if (n.nodeType == Node.ELEMENT_NODE)
            iconify(n);
});
ob.observe(document, {subtree:true, childList:true});