// ==UserScript==
// @name         Wiki Randomizer
// @namespace    https://script.zgc.im/
// @version      1.1.0
// @description  Press 'R' to jump to a random wiki page.
// @author       MidAutumnMoon
//
// @include /^https://.*\.wikipedia\.org/.*$/
// @include /^https://.*\.fandom\.com/.*$/
// @include /^https://.*\.moegirl\.org\.cn/.*$/
// @match https://tcrf.net/*
// @match https://wiki.archlinux.org/*
// @match https://wiki.debian.org/*
//
// @icon         https://zh.wikipedia.org/favicon.ico
// @grant        none
// @downloadURL none
// ==/UserScript==

// The default trigger key
const THAT_KEY = 'F8';

// Almost any Mediawiki sites use /Special:Random.
const MediawikiCommon = 'Special:Random';

const MediawikiRootpageCommon = 'Special:RandomRootpage';

const MoinMoinCommon = 'RandomPage';

// The total rules
const RULES = new Map([
  // *.wikipedia.org
  [ 'wikipedia.org', 'wiki/'+MediawikiCommon ],

  // Cutting Room Floor
  [ 'tcrf.net', MediawikiRootpageCommon ],

  // 萌百！
  [ 'moegirl.org.cn', MediawikiCommon ],

  // Fandom
  [ 'fandom.com', 'wiki/'+MediawikiRootpageCommon ],

  // Arch Linux wiki
  [ 'wiki.archlinux.org', 'index.php/'+MediawikiCommon ],

  // Debian wiki
  [ 'wiki.debian.org', MoinMoinCommon ],
]);

// Main
(function() {
  'use strict';

  // Navigate to the `location` of current site.
  const navigate_to = ( location ) => {
    window.location.href = new URL( window.location.href ).origin + '/' + location;
  };

  // Get the rule associated with current site.
  const get_rule = () => {
    let domain = new URL( window.location.href ).host;
    let rule = '';

    for (;;) {
      rule = RULES.get(domain);

      if ( rule === undefined ) {
        // If no rules were found for current domain,
        // try matching 1 level upper instead.
        if ( ! validated_domain(domain) ) {
          return null;
        }
        // truncate one level of subdomain
        domain = domain.substring( domain.indexOf('.') + 1 );
      } else {
        // Otherwise just return the matched rule.
        return rule;
      }
    }

  };

  // There must be at least 2 dots in a valid domain name.
  const validated_domain = ( domain ) => {
    return ( (domain.match(/\./g) || []).length >= 2 );
  };

  // make codes clearer
  const main = () => {
    const location = get_rule();

    switch ( location ) {
      case null:
        console.log( 'No rules for current site!' );
        break;
      default:
        navigate_to( location );
        break;
    }
  };

  // ...when press 'R'.
  document.addEventListener('keydown', ( event ) => {
    if ( event.code === THAT_KEY )
      main();
  });

})();