// ==UserScript==
// @name          Yahoo direct non-tracking search
// @description   Strips tracking and redirection from Yahoo search urls
// @include       https://search.yahoo.com/search*
// @version       1.0
// @author        wOxxOm
// @namespace     wOxxOm.scripts
// @license       MIT License
// @grant         none
// @run-at        document-start
// @downloadURL none
// ==/UserScript==

setMutationHandler(document, '.search-assist-form-wrapper form, a', function(observer, nodes) {
  Array.prototype.forEach.call(nodes, function(node) {
    switch (node.localName) {
      case 'form':
        node.addEventListener('submit', function(e){
          e.preventDefault();
          e.stopPropagation();
          e.target.action = 'https://search.yahoo.com/search;';
          e.target.submit();
        });
        break;
      case 'a':
        node.href = node.href.replace(/;?_yl[tu]=[\w;_=.-]+\/?/, '')
                             .replace(/^.+?\/RU=(http[^\/]+)\/?.*$/, function(s, url) { return decodeURIComponent(url) });
        break;
    }
  });
  return true;
});

function setMutationHandler(baseNode, selector, cb) {
  var ob = new MutationObserver(function(mutations){
    for (var i=0, ml=mutations.length, m; (i<ml) && (m=mutations[i]); i++)
      for (var j=0, nodes=m.addedNodes, nl=nodes.length, n; (j<nl) && (n=nodes[j]); j++)
        if (n.nodeType == 1) 
          if ((n = n.matches(selector) ? [n] : n.querySelectorAll(selector)) && n.length)
            if (!cb(ob, n))
              return;
  });
  ob.observe(baseNode, {subtree:true, childList:true}); 
}