// CDJ-900NXS Mods — small helpers: theme toggle, before/after slider, docs TOC highlight.
(function () {
  var root = document.documentElement;

  function storedTheme() {
    try { return localStorage.getItem('theme'); } catch (e) { return null; }
  }
  var t = storedTheme();
  if (t === 'light' || t === 'dark') root.setAttribute('data-theme', t);

  document.addEventListener('DOMContentLoaded', function () {
    var btn = document.querySelector('.theme-btn');
    function label() {
      if (btn) btn.textContent = root.getAttribute('data-theme') === 'light' ? '☾' : '☀';
    }
    label();
    if (btn) btn.addEventListener('click', function () {
      var next = root.getAttribute('data-theme') === 'light' ? 'dark' : 'light';
      root.setAttribute('data-theme', next);
      try { localStorage.setItem('theme', next); } catch (e) { /* private mode */ }
      label();
    });

    // version badge and changelog (assets/versions.js, made by tools/make_builder_data.py)
    var V = window.CDJ_VERSIONS;
    var head = document.querySelector('.top .wrap');
    if (V && head) {
      var esc = function (t) { return String(t).replace(/[&<>]/g, function (c) { return { '&': '&amp;', '<': '&lt;', '>': '&gt;' }[c]; }); };
      var vb = document.createElement('button');
      vb.type = 'button'; vb.className = 'ver-btn'; vb.textContent = 'v' + V.site;
      vb.setAttribute('aria-haspopup', 'dialog'); vb.title = 'Changelog';
      var brand = head.querySelector('.brand');
      if (brand && brand.nextSibling) head.insertBefore(vb, brand.nextSibling); else head.appendChild(vb);
      var pop = document.createElement('div');
      pop.className = 'ver-pop'; pop.setAttribute('role', 'dialog'); pop.setAttribute('aria-label', 'Changelog');
      var html = '<div class="ver-box"><button class="close" type="button" aria-label="Close">✕</button>' +
        '<h2>Changelog</h2><p class="sub">Site ' + esc(V.site) + ' · ' + esc(V.date) + ' · Semantic Versioning, dates ISO 8601</p>';
      V.log.forEach(function (e) {
        html += '<h3>' + esc(e.version) + '<span class="d">' + esc(e.date) + '</span></h3><ul>' +
          e.changes.map(function (c) { return '<li>' + esc(c) + '</li>'; }).join('') + '</ul>';
      });
      html += '<h3>Mods</h3><div class="ver-mods">' + Object.keys(V.mods).map(function (m) {
        return '<code>' + esc(m) + '</code><span>' + esc(V.mods[m]) + '</span>';
      }).join('') + '</div></div>';
      pop.innerHTML = html;
      document.body.appendChild(pop);
      var close = function () { pop.classList.remove('open'); vb.focus(); };
      vb.addEventListener('click', function () { pop.classList.add('open'); pop.querySelector('.close').focus(); });
      pop.querySelector('.close').addEventListener('click', close);
      pop.addEventListener('click', function (e) { if (e.target === pop) close(); });
      document.addEventListener('keydown', function (e) { if (e.key === 'Escape' && pop.classList.contains('open')) close(); });
      // every mod card's version beside its name
      document.querySelectorAll('.card h3 code').forEach(function (c) {
        var v = V.mods[c.textContent.trim()];
        if (v) { var s = document.createElement('span'); s.className = 'ver'; s.textContent = 'v' + v; c.parentNode.appendChild(s); }
      });
    }

    // before / after
    document.querySelectorAll('.compare').forEach(function (box) {
      var range = box.querySelector('input[type="range"]');
      if (!range) return;
      function set() { box.style.setProperty('--pos', range.value + '%'); }
      range.addEventListener('input', set);
      set();
    });

    // docs: highlight the section in view
    var links = Array.prototype.slice.call(document.querySelectorAll('.toc a[href^="#"]'));
    if (links.length && 'IntersectionObserver' in window) {
      var byId = {};
      links.forEach(function (a) { byId[a.getAttribute('href').slice(1)] = a; });
      var obs = new IntersectionObserver(function (entries) {
        entries.forEach(function (e) {
          if (e.isIntersecting && byId[e.target.id]) {
            links.forEach(function (a) { a.classList.remove('active'); });
            byId[e.target.id].classList.add('active');
          }
        });
      }, { rootMargin: '-80px 0px -70% 0px' });
      Object.keys(byId).forEach(function (id) {
        var el = document.getElementById(id);
        if (el) obs.observe(el);
      });
    }
  });
})();