// ==UserScript== 
// @name Restore O12 space bar behavior
// @version 0.19 
// @author Roland "QuHno" Reck 
// @include http://*.* 
// @include https://*.* 
// ==/UserScript== 
(function (window) {
  "use strict";
  /*jshint browser: true, devel: false, debug: true, evil: true, forin: true, undef: true, bitwise: true, eqnull: true, noarg: true, noempty: true, eqeqeq: true, boss: true, loopfunc: true, laxbreak: true, strict: true, curly: true, nonew: true */
  function is_number(obj) {
    return !isNaN(obj - 0);
  }
  function make_ipattern(string) {
    return '/' + string + '/i';
  }
  function split_hash(obj) {
    //return (url + '#a').split('#')[0];
    return (obj.pathname + obj.search);
  }
  function getScrollMaxY() {
    return document.documentElement.scrollHeight - document.documentElement.clientHeight;
  }
  function scrollToPos(el, x, y) {
    el.scrollLeft = x;
    el.scrollTop = y;
  }
  var i,
  j,
  HREF = split_hash(window.location),
  PROTOCOL = window.location.protocol,
  HOST = window.location.host,
  HOSTPATTERN = make_ipattern(HOST),
  A,
  LRN,
  theParent,
  searchDepth,
  stop = false,
  linkContainer = false,
  regexps = {
    trim: /^\s+|\s+$/g,
    normalize: /\s{2,}/g,
    relLink: /^next$/gi,
    nextLink: /(Next\s*(page)?|Neste\s*(side)?|N(ä|ae)chste\s*(Seite)?|Weiter(e.*)?|Vorw(ä|ae)rts|Volg(ende)?\s*(bladsy|pagina)?|Verder|(Page)?\s*Suiv(ant)?(e)?(s)?|(Page)?\s*(prochaine)|Avanti|(Pag(ina)?)?\s*Succ(essiv(e|a|o)|Prossim(e|a|o))|Altr(a|o)|(P(á|a)gina)?\s*(S(e|i)guie?nte)|Próxim(a|os?)|Nästa\s*(sida)?|Næste?\s*(side)?|下一頁|下一页|Sonraki|Следующая|Далее| 下一页|下一张|下一篇|下一章|下一节|下一步|下一个|下页|后页|下一頁|下一張|下一節|下一個|下頁|後頁|다음|다음\s*페이지|次へ|Seuraava|Επόμενη|Следващ(а|о|и)\s*(страница|сайт)?|Нататък|След(в|н)а|(Пълен)?\s*Напред|Dalej|Następn(a|e|y)|Więcej|Tovább|Köv(etkező|\.)|Bővebben|Înaint(ar)?e(ază)?|Avansează|(Pagina\s*)?Următoa?r(e|ul)?|>([^\|]|$)|»([^\|]|$)|→)/i,
    extraneous: /print|archive|comment|discuss|e[\-]?mail|share|reply|all|login|sign|single|teaser/i,
    back: /(back|prev|earl|old|new|zurück|vorige|rückwärts|назад|<|«)/i,
    images: /\.jpe?g$|\.png$|\.webp$|\.gif$/i,
    cut: /[?#]/
  },
  actHREF,
  prevHREF,
  imageResult,
  shouldImagePreview = false,
  shouldFF = false,
  UUID = '43D82723-A99E-4BFD-ACDC-B7D8270EE75C';


  /* *********************************************************************************************
  FIND LINK TO NEXT PAGE
   */
  function analyze() {

    HREF = split_hash(window.location);
    PROTOCOL = window.location.protocol;
    HOST = window.location.host;
    HOSTPATTERN = make_ipattern(HOST);
    LRN = false;
    linkContainer = false;

    //* STEP 1: Look if the webmaster knew rel=  *//
    // If there is a <link rel="next" ... and it it points to the same origin: Use it.
    LRN = document.querySelector('link[rel="next"]');
    if (!!LRN && LRN.href.indexOf(window.location.origin) < 0) {
      LRN = false;
    }
    // If there is a <A rel="next" ... and it it points to the same origin: Use it.
    if (!LRN) {
      linkContainer = document.body.querySelector('A[rel="next"]');
      if (!!linkContainer && linkContainer.href.indexOf(window.location.origin) < 0) {
        linkContainer = false;
      }
    }

    if (!linkContainer) {

      A = document.body.querySelectorAll('A');
      for (i = 1, j = A.length - 2; i < j; [i++]) {
        // Skip this link if does not have the same origin
        if (A[i].href.indexOf(window.location.origin) < 0) {
          continue;
        }

        //* STEP 2: Try to find out if the classes and IDs of the parent elements give a hint on the next link. *//
        actHREF = split_hash(A[i]);
        prevHREF = split_hash(A[i - 1]);
        theParent = A[i];

        // We limit the search depth to 6 to avoid wading through too many elements
        searchDepth = 6;

        stop = false;
        while (searchDepth > 0 && stop === false && theParent.parentElement && theParent.parentElement !== document.body) {
          /*
          if (!theParent.parentElement) {
          // searchDepth = 0;
          break;
          }
           */

          theParent.classAndId = theParent.className + ' z ' + theParent.id;
          searchDepth = searchDepth - 1;

          // This is quite probably the wrong link.
          // May be this should be done outside of the loop because some navigations contain classes like "prev next" in the parent elements
          if (theParent.classAndId.match(regexps.back)) {
            stop = true;
            break;
          }

          // If we don't get "hard evidence" we don't want links in print or discussion things
          if (theParent.classAndId.match(regexps.extraneous)) {
            // stop = true;
            break;
          }

          // this could be the next link, if there is no better match later
          if (theParent.classAndId.match(regexps.nextLink)) {
            linkContainer = A[i];
          }
          theParent = theParent.parentElement;
        }
        //*
        // seems this hurts more than it is worth the time it saves
        if (stop) {
          continue;
        }
        // stop = false;
        //*/

        //* STEP 3: Look for numbered pagination like e.g. in forums *//
        if (is_number(A[i].textContent) && A[i].textContent > 0) {
          if (is_number(A[i - 1].textContent) === false || (A[i - 1].textContent - 0 === 0)) {
            if (is_number(A[i + 1].textContent) && A[i + 1].textContent > 0 && actHREF !== HREF && A[i].textContent !== '1') {
              linkContainer = A[i];
              continue;
            }
          }
          if (is_number(A[i - 1].textContent) && A[i - 1].textContent > 0) {

            // if the previous link is to the page where we are right now it is quite possible that this is the link to the next page
            if (prevHREF === HREF) {
              linkContainer = A[i];
              continue;

              // this is for skipped pagination where the actual page is not linked, so the link to the previous page is 2 lower than that to the next page.
            } else if ((A[i].textContent - A[i - 1].textContent - 0) === 2) {
              linkContainer = A[i];
              continue;
            }
          }
          // I don't know anymore why this was important, but it breaks somewhere if this is not in.
          if (prevHREF === HREF) {
            linkContainer = A[i];
            continue;
          }
        }

        //* STEP 4: Match IDs. Almost as good as rel, therefore: If there is a good ID, we take it and stop searching *//
        if (A[i].id) {
          if (A[i].id.match(regexps.nextLink)) {
            linkContainer = A[i];
            break;
          }
        }

        //* STEP 5: CLASSes are weaker than ID, so store but don't stop. If there is no better Link we take it. *//
        if (A[i].className) {
          if (A[i].className.match(regexps.nextLink)) {
            linkContainer = A[i];
            continue;
          }
        }

        //* STEP 6: We are down to textContent - quite weak, but better than nothing *//
        if (A[i].textContent) {
          if (A[i].textContent.replace(/\s+/g, ' ').length < 25 && A[i].textContent.match(regexps.nextLink)) {
            linkContainer = A[i];
            continue;
          }
        }

        //* STEP 7: TITLE, even weaker ... *//
        if (A[i].getAttribute("title")) {
          if (A[i].textContent.replace(/\s+/g, ' ').length < 25 && A[i].getAttribute("title").match(regexps.nextLink)) {
            linkContainer = A[i];
            continue;
          }
        }

      }

    }

    // Comment this out if you don't want a hint about the next link
    // set borders _and_ outlines because in most cases websites don't alter both at the same time
    if (!!linkContainer) {
      linkContainer.style.border = '1px solid #FF0000';
      linkContainer.style.outline = '1px solid #FFff00';
      if (!document.querySelector('a[rel="next"]')) {
        linkContainer.setAttribute('rel', 'next');
        // Experimental: Maybe the Fast Forward button reacts on that at some time in the future ... probably not.
        var evt = document.createEvent('Event');
        evt.initEvent('load', false, false);
        window.dispatchEvent(evt);
      }
    }
  }
  function doFastForward() {
    /* Hard coded exceptions for fucked up search engine pages */
    var temp = null;
    /* extra saussage for startpage.com */
    if (HOST.indexOf('startpage.com') > -1) {
      temp = document.querySelector('#nextnavbar > form > a > span.i_next');
      console.log('startpage.com fucked up');
      temp.click();
      return false;
    }

    /* Normal stuff */
    /* we've got a hard link rel */
    if (LRN && LRN.href) {
      window.location.href = LRN.href;
      return false;
    }
    if (!!linkContainer) {
      linkContainer.click();
    }
  }

  var handleKeyDown = function (e) {
    if (e.key === "PageDown" && shouldFF) {
      doFastForward();
    }
    // Don't space2next if the focus is in an editable area
    // Did I forget something?
    if (/INPUT|SELECT|TEXTAREA|CANVAS/.test(e.target.tagName) || e.target.isContentEditable || document.designMode === 'on') {
      return;
    }

    // ToDo: If there are linked imageExtensions, add the logic to show them

    // If the page is already scrolled to the bottom and the user hits space, go to the next page if a link was found.
    if (e.keyCode === 32 && shouldFF) {
      doFastForward();
    }
  };

  window.addEventListener('scroll', function (e) {

    // don't analyze if the user did not scroll to the bottom
    if (window.scrollY >= getScrollMaxY() && window.scrollY > 0) {
      analyze();
      shouldFF = true;
    } else if (window.scrollY < getScrollMaxY()) {
      console.log(shouldFF);
      shouldFF = false;
    }
  }, false);
  window.addEventListener('keydown', handleKeyDown, false);
})(window);