/** Article directory: one renderer for sidebar, affix and mobile copies. */
(function () {
  'use strict';

  var entries = [];
  var rendered = new WeakMap();
  var framePending = false;
  var handledHash = '';

  function hashId(hash) {
    try { return decodeURIComponent(hash.slice(1)); }
    catch (error) { return ''; }
  }

  function collectHeadings() {
    var found = [];
    document.querySelectorAll('[data-nav] h1, [data-nav] h2, [data-nav] h3, [data-nav] h4').forEach(function (heading, index) {
      var text = (heading.textContent || '').trim();
      if (!text || heading.classList.contains('item-heading') || heading.closest('.no-nav')) return;
      if (!heading.id || document.getElementById(heading.id) !== heading) {
        var id = 'wznav_' + index;
        var suffix = 0;
        while (document.getElementById(id)) id = 'wznav_' + index + '_' + (++suffix);
        heading.id = id;
      }
      found.push({ element: heading, id: heading.id, text: text, tag: heading.tagName.toUpperCase() });
    });
    return found;
  }

  function groupChildren(item) {
    var children = [];
    var next = item.nextElementSibling;
    while (next && !next.classList.contains('n-H1') && !next.classList.contains('n-H2')) {
      children.push(next);
      next = next.nextElementSibling;
    }
    return children;
  }

  function collapseGroups(list) {
    if (list.scrollHeight <= 380 || list.querySelector('.nav-toggle-collapse')) return;
    list.querySelectorAll('.n-H1, .n-H2').forEach(function (item) {
      var children = groupChildren(item);
      if (!children.length) return;
      children.forEach(function (child) { child.classList.add('yc'); });
      var button = document.createElement('button');
      button.type = 'button';
      button.className = 'fa fas fa-angle-right nav-toggle-collapse';
      button.setAttribute('aria-expanded', 'false');
      button.setAttribute('aria-label', item.querySelector('a').textContent);
      item.appendChild(button);
    });
  }

  function fillBox(box, signature) {
    if (entries.length < 3) {
      if (box.dataset.aksrtSectionNav === '1') {
        box.replaceChildren();
        delete box.dataset.aksrtSectionNav;
        rendered.delete(box);
      }
      return;
    }
    if (rendered.get(box) === signature) {
      var current = box.querySelector('.bl');
      if (current) collapseGroups(current);
      return;
    }
    box.replaceChildren();
    box.dataset.aksrtSectionNav = '1';
    rendered.set(box, signature);
    var title = box.getAttribute('data-title') || '';
    if (title) {
      var titleBody = document.createElement('div');
      titleBody.className = 'box-body notop';
      var titleText = document.createElement('div');
      titleText.className = 'title-theme';
      // data-title is escaped by the PHP renderer, including its optional small tag.
      titleText.innerHTML = title;
      titleBody.appendChild(titleText);
      box.appendChild(titleBody);
    }
    var widget = document.createElement('div');
    widget.className = 'zib-widget';
    var nav = document.createElement('div');
    nav.className = 'posts-nav-lists scroll-y mini-scrollbar list-unstyled';
    var list = document.createElement('ul');
    list.className = 'bl relative nav';
    entries.forEach(function (entry) {
      var item = document.createElement('li');
      item.className = 'n-' + entry.tag;
      var link = document.createElement('a');
      link.className = 'text-ellipsis';
      link.setAttribute('href', '#' + encodeURIComponent(entry.id));
      link.textContent = entry.text;
      item.appendChild(link);
      list.appendChild(item);
    });
    nav.appendChild(list);
    widget.appendChild(nav);
    box.appendChild(widget);
    collapseGroups(list);
  }

  function scrollspy() {
    if (entries.length < 3) return;
    var current = '';
    entries.forEach(function (entry) {
      if (!entry.element.getClientRects().length) return;
      if (entry.element.getBoundingClientRect().top <= 105) current = entry.id;
    });
    document.querySelectorAll('.posts-nav-lists a[href^="#"]').forEach(function (link) {
      var active = hashId(link.getAttribute('href')) === current;
      link.parentElement.classList.toggle('active', active);
      if (active) link.setAttribute('aria-current', 'location');
      else link.removeAttribute('aria-current');
    });
  }

  function scheduleSpy() {
    if (framePending) return;
    framePending = true;
    window.requestAnimationFrame(function () {
      framePending = false;
      scrollspy();
    });
  }

  function scrollToHeading(target) {
    // Reference behavior: reveal content hidden by an accordion or height limit.
    var panels = jQuery(target).parents('.panel').find('.collapse');
    if (typeof panels.collapse === 'function') panels.collapse('show');
    document.querySelectorAll('.read-more-open').forEach(function (button) { button.click(); });
    document.body.classList.remove('mobile-navbar-show');
    var header = document.querySelector('.header');
    var offset = document.body.classList.contains('nav-fixed') && header ? header.offsetHeight + 20 : 0;
    var reduced = window.matchMedia && window.matchMedia('(prefers-reduced-motion: reduce)').matches;
    window.scrollTo({ top: Math.max(0, target.getBoundingClientRect().top + window.pageYOffset - offset), behavior: reduced ? 'auto' : 'smooth' });
    scheduleSpy();
  }

  function followHash() {
    var hash = window.location.hash;
    if (!hash || hash === handledHash) return;
    var id = hashId(hash);
    var entry = entries.find(function (item) { return item.id === id; });
    if (!entry || entries.length < 3) return;
    handledHash = hash;
    window.setTimeout(function () { scrollToHeading(entry.element); }, 20);
  }

  function init() {
    entries = collectHeadings();
    var signature = JSON.stringify(entries.map(function (entry) { return [entry.id, entry.text, entry.tag]; }));
    document.querySelectorAll('.posts-nav-box').forEach(function (box) {
      fillBox(box, signature + (box.getAttribute('data-title') || ''));
    });
    scrollspy();
    followHash();
  }

  document.addEventListener('click', function (event) {
    var button = event.target.closest('.posts-nav-lists .nav-toggle-collapse');
    if (button) {
      event.preventDefault();
      var expanded = button.getAttribute('aria-expanded') !== 'true';
      button.setAttribute('aria-expanded', String(expanded));
      button.classList.toggle('fa-rotate-90', expanded);
      groupChildren(button.parentElement).forEach(function (child) { child.classList.toggle('yc', !expanded); });
      return;
    }
    var link = event.target.closest('.posts-nav-lists a[href^="#"]');
    if (!link) return;
    var target = document.getElementById(hashId(link.getAttribute('href')));
    if (!target) return;
    event.preventDefault();
    scrollToHeading(target);
  });
  window.addEventListener('scroll', scheduleSpy, { passive: true });
  window.addEventListener('resize', init, { passive: true });
  window.addEventListener('hashchange', followHash);
  jQuery(document).off('auto_fun.aksrt-section-navs').on('auto_fun.aksrt-section-navs', init);
  if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', init, { once: true });
  else init();
})();