// Shared voice-library cache. The backend index is authoritative; this layer
// prevents multiple frontend panels from starting duplicate scans in one tab.
(function installVoiceLibraryCache() {
  const KEY = 'ttsvc_voice_library_cache_v2';
  const MAX_AGE_MS = 30_000;
  let inFlight = null;

  function read() {
    try {
      const value = JSON.parse(sessionStorage.getItem(KEY) || 'null');
      if (!value || !Array.isArray(value.voices) || !Number.isFinite(value.savedAt)) return null;
      return Date.now() - value.savedAt <= MAX_AGE_MS ? value.voices : null;
    } catch (_) { return null; }
  }
  function write(voices) {
    try { sessionStorage.setItem(KEY, JSON.stringify({ savedAt: Date.now(), voices })); } catch (_) {}
  }
  function invalidate() {
    try { sessionStorage.removeItem(KEY); } catch (_) {}
  }
  async function fetchVoices(options = {}) {
    const refresh = options === true || options.refresh === true;
    if (!refresh) {
      const cached = read();
      if (cached) return cached;
    }
    if (inFlight) return inFlight;
    inFlight = fetch('/api/voices' + (refresh ? '?refresh=1' : ''), { cache: 'no-store' })
      .then(async response => {
        if (!response.ok) { const error = await response.json().catch(() => ({})); throw new Error(error.detail || response.statusText); }
        const voices = await response.json();
        if (!Array.isArray(voices)) throw new Error('Voice library response was not an array');
        write(voices);
        return voices;
      })
      .finally(() => { inFlight = null; });
    return inFlight;
  }
  window.fetchVoiceLibrary = fetchVoices;
  window.invalidateVoiceLibraryCache = invalidate;
})();