// ==UserScript==
// @name           GoogleBilingual
// @version        1.0.0
// @license        MIT license
// @namespace      http://d.hatena.ne.jp/snaka72/
// @require        http://gist.github.com/raw/3242/9dc0cdee5e975d275c7ab71f581d272eb316674f/dollarX.js
// @require        http://gist.github.com/raw/155402/f48c73c53d8858ded9ad1edaaa922b29bb0ecf2f/HTMLStringToDOM.js
// @include        http://www.google.com/*
// @include        http://www.google.co.jp/*
// ==/UserScript==
(function() {
  // Main //////////////////////////////////////////////////////////////{{{
  var other = new SearchEngine( getCurrentLang() == 'en' ? 'ja' : 'en');
  $X('id("res")/div[ol or div]', document).forEach(function(rightPart) {
    other.insertSearchResults(rightPart, window.location);
  });

  // register page handler
  function registerNextPageHandler() {
    var nextUrl
    window.AutoPagerize.addDocumentFilter(function(doc, url) {
      nextUrl = new URI(url);
    });
    window.AutoPagerize.addFilter(function(bodies) {
      bodies.forEach(function(body) {
        other.insertSearchResults(body, nextUrl);
      });
    });
  }

  // register next page handler
  if (window.AutoPagerize) {
    registerNextPageHandler()
  } else {
    window.addEventListener('GM_AutoPagerizeLoaded', registerNextPageHandler, false);
  }
  // }}}
  // Class /////////////////////////////////////////////////////////////{{{
  function SearchEngine(lang) {
    this.lang = lang;

    this.insertSearchResults = function(rightPart, uri) {

      // resize search result
      //var rightPart = $X('id("res")/div[ol or div]', doc)[0];
      rightPart.style.position = 'relative';
      $X('./ol', rightPart)[0].style.width = '48%';

      // modify querystring for counter part
      var queryString = uri.search;
      queryString = queryString.replace(/([?&])hl=\w\w/, '$1hl=' + this.lang);
      queryString = queryString.replace(/([?&])lr=lang_\w\w/, '$1lr=lang_' + this.lang);
      var searchUrl = uri.protocol + '//' + uri.host + uri.pathname + queryString;

      // get counter part
      GM_xmlhttpRequest({
        method: 'GET',
        url: searchUrl,
        onload: function(res) {
          var dom = HTMLStringToDOM(res.responseText);
          var leftPart = $X('id("res")/div[ol or div]', dom)[0];
          with(leftPart.style) {
            position = 'absolute';
            width = '48%';
            top = '-16px';
            right = '0';
          }

          rightPart.appendChild(leftPart);
          var height = Math.max(leftPart.clientHeight, rightPart.clientHeight);
          rightPart.style.height = height + 'px';
        }
      });
    };
  }
  // }}}
  // Misc functions ////////////////////////////////////////////////////{{{

  function getCurrentLang() {
    var queryString = window.location.search;
    if (match = queryString.match(/[?&]hl=(\w\w)/)) {
      return match[1];
    }
    return 'en'
  }

  // URI constructor >>>
  // from (http://d.hatena.ne.jp/javascripter/20090309/1236590529)
  // by   javascripter
  function URI(uri) {
    uri = String(uri);
    var parser = /^([^:/?#]+:)?\/\/(([^/?#:]*):?(\d*))?([^?#]*)(\?[^#]*)?(#.*)?$/;
    var m = uri.match(parser);
    if (!m) throw new URIError("malformed URI given");
    this.href = m[0];
    this.protocol = m[1] || "";
    this.host = m[2] || "";
    this.hostname = m[3] || "";
    this.port = m[4] || "";
    this.pathname = m[5] || "";
    this.search = m[6] === "?" ? "" : m[6] || "";
    this.hash = m[7] || "";
  }

  URI.prototype.toString = function () {
    return this.href;
  };
  // <<< URI constructor

  function debug(msg, obj) {
    dump(msg + ': ' + obj + '\n');
  }

  // }}}
})();
// vim: sw=2 ts=2 et fdm=marker