(async function () {
  'use strict';

  const SECTIONS = [
    's-voices', 's-clone', 's-design', 's-studio', 's-tryout',
    's-performance', 's-routing', 's-connect', 's-settings',
    's-llms', 's-conversation',
  ];

  // ── Fetch app version once for JS cache-busting ──────────────────────────
  // JS files are served with ?v=<version> so the browser can cache them
  // aggressively.  Sections use Date.now() to always get fresh HTML.
  var _appVersion = 'dev';
  try {
    var _vr = await fetch('/api/version');
    var _vd = await _vr.json();
    _appVersion = _vd.version || _appVersion;
  } catch (_) {}

  // ── 1. Fetch all section HTML partials in parallel ────────────────────────
  var _ts = Date.now(); // sections always fresh during a session
  await Promise.all(SECTIONS.map(async function (id) {
    try {
      var res = await fetch('/static/sections/' + id + '.html?v=' + _ts);
      if (!res.ok) throw new Error(res.status + ' ' + res.statusText);
      var el = document.getElementById(id);
      if (el) el.innerHTML = await res.text();
    } catch (e) {
      console.error('[loader] section', id, 'failed:', e.message);
      var el = document.getElementById(id);
      if (el) el.innerHTML =
        '<p style="color:var(--red);padding:24px">Failed to load section <b>' +
        id + '</b>: ' + e.message + '</p>';
    }
  }));

  // ── 2. Load JS in parallel batches ────────────────────────────────────────
  // Scripts with async=false are FETCHED in parallel but EXECUTED in DOM
  // insertion order — safe for modules that share a global scope.
  //
  // Batch order:
  //   A) utils.js          — defines $, toast, escHtml; needed by everything
  //   B) settings.js       — declares _appSettings; needed before features read it
  //   C) Feature modules   — parallel fetch + ordered execute
  //   D) init.js           — calls loadSettings() + initBenchmarkSampleControls()
  //   E) Post-init modules — parallel fetch + ordered execute
  //   F) nav.js            — navigation overrides; must be last

  function _load(src) {
    return new Promise(function (resolve, reject) {
      var s = document.createElement('script');
      s.src = src + '?v=' + _appVersion;
      s.async = false;   // fetch in parallel, execute in DOM order
      s.onload  = resolve;
      s.onerror = function () { reject(new Error('Failed to load ' + src)); };
      document.body.appendChild(s);
    });
  }

  function _loadBatch(srcs) {
    // Append all <script async=false> at once → browser fetches all in parallel
    // and executes them in the order they were appended.
    return Promise.all(srcs.map(_load));
  }

  // A — foundation (sequential: each must finish before the next batch starts)
  await _load('/static/js/utils.js');
  await _load('/static/js/settings.js');

  // C — feature modules (9 files fetched in parallel, executed in order)
  await _loadBatch([
    '/static/js/voice-inspector.js',
    '/static/js/voice-sources.js',
    '/static/js/integrations.js',
    '/static/js/routing.js',
    '/static/js/voice-clone.js',
    '/static/js/voice-library.js',
    '/static/js/tts-preview.js',
    '/static/js/benchmark.js',
    '/static/js/stt.js',
  ]);

  // D — init (needs everything above to be defined)
  await _load('/static/js/init.js');

  // E — post-init modules (4 files fetched in parallel, executed in order)
  await _loadBatch([
    '/static/js/engines.js',
    '/static/js/ai-backends.js',
    '/static/js/generation.js',
    '/static/js/conversation.js',
  ]);

  // F — navigation
  await _load('/static/nav.js');
})();