/* SAN AVELIO - CHARACTER CARD AUTO FOCUS v2
   Replacement for 34304.txt. Keeps the same Forumstatic connection.
   Targets the real Character Studio root: #sa-st5. */
(function(){
  'use strict';

  /* Allow this replacement to work even if an older cached v1 flag exists. */
  window.SA_CHARACTER_CARD_AUTO_FOCUS_V1 = true;
  if (window.SA_CHARACTER_CARD_AUTO_FOCUS_V2) return;
  window.SA_CHARACTER_CARD_AUTO_FOCUS_V2 = true;

  var start = Date.now();
  var maxWait = 10000;
  var settled = false;
  var observer = null;

  function isTopic(){
    return /viewtopic\.php/i.test(location.href) ||
      !!document.querySelector('.topic .post,#pun-main .post,.topicpost');
  }

  function target(){
    /* This is the actual root created by Character Studio v15/v14. */
    var el = document.querySelector('#sa-st5');
    if (el && el.getClientRects().length) return el;
    return null;
  }

  function pageY(el){
    var r = el.getBoundingClientRect();

    /* getBoundingClientRect already reflects CSS zoom in Chromium.
       pageYOffset gives the document position without us guessing the forum scale. */
    return Math.max(0, Math.round(r.top + (window.pageYOffset || document.documentElement.scrollTop || 0)));
  }

  function jump(el){
    if (!el) return;

    var y = pageY(el);

    /* Put the actual dossier top at the viewport top.
       No smooth animation: the user should arrive there immediately. */
    window.scrollTo({top:y,left:0,behavior:'auto'});

    /* Some SAN AVELIO/Rusff blocks settle after the first paint.
       Recalculate instead of reusing the old Y coordinate. */
    requestAnimationFrame(function(){
      window.scrollTo(0,pageY(el));
    });
  }

  function lockOn(el){
    if (settled) return;
    jump(el);

    /* Images/fonts/typography patch may still shift the post.
       Keep correcting only during initial page load. */
    [80,180,350,650,1100,1700].forEach(function(ms){
      setTimeout(function(){
        if (!settled) jump(el);
      },ms);
    });

    setTimeout(function(){
      jump(el);
      settled = true;
      if (observer) observer.disconnect();
    },2200);
  }

  function attempt(){
    if (settled || !isTopic()) return;
    var el = target();
    if (el){
      lockOn(el);
      return;
    }
    if (Date.now()-start > maxWait){
      settled = true;
      if (observer) observer.disconnect();
    }
  }

  function boot(){
    if (!isTopic()) return;

    attempt();

    if (window.MutationObserver){
      observer = new MutationObserver(attempt);
      observer.observe(document.querySelector('#pun-main') || document.body,{
        childList:true,
        subtree:true
      });
    }

    var timer = setInterval(function(){
      attempt();
      if (settled) clearInterval(timer);
    },100);

    setTimeout(function(){
      clearInterval(timer);
      if (observer) observer.disconnect();
    },maxWait+500);
  }

  if (document.readyState === 'loading'){
    document.addEventListener('DOMContentLoaded',boot,{once:true});
  } else {
    boot();
  }
})();