// Keyless YouTube metadata: id parsing plus title lookup via the public oEmbed
// endpoint. Durations are not available here — they come from the probe player
// in the player frontend and arrive over the socket later.

const ID_PATTERN = /^[A-Za-z0-9_-]{11}$/;

/**
 * Pull the 11-character video id out of anything a user might paste.
 * Returns null when the input is not a recognisable YouTube video.
 */
export function parseVideoId(input) {
  const raw = String(input || '').trim();
  if (!raw) return null;

  // A bare id pasted on its own.
  if (ID_PATTERN.test(raw)) return raw;

  let url;
  try {
    url = new URL(raw.includes('://') ? raw : `https://${raw}`);
  } catch {
    return null;
  }

  const host = url.hostname.replace(/^www\./, '');
  const segments = url.pathname.split('/').filter(Boolean);

  if (host === 'youtu.be') {
    return ID_PATTERN.test(segments[0]) ? segments[0] : null;
  }

  if (host === 'youtube.com' || host === 'm.youtube.com' || host === 'music.youtube.com' || host === 'youtube-nocookie.com') {
    const v = url.searchParams.get('v');
    if (v && ID_PATTERN.test(v)) return v;

    // /shorts/ID, /embed/ID, /live/ID, /v/ID
    if (['shorts', 'embed', 'live', 'v'].includes(segments[0])) {
      return ID_PATTERN.test(segments[1]) ? segments[1] : null;
    }
  }

  return null;
}

/**
 * Fetch the video title. Falls back to the id so a failed lookup still leaves
 * a usable queue entry rather than blocking the add.
 */
export async function fetchTitle(videoId) {
  const endpoint = `https://www.youtube.com/oembed?url=${encodeURIComponent(
    `https://www.youtube.com/watch?v=${videoId}`,
  )}&format=json`;

  try {
    const res = await fetch(endpoint, { signal: AbortSignal.timeout(8000) });
    if (!res.ok) throw new Error(`oembed ${res.status}`);
    const data = await res.json();
    return data.title || videoId;
  } catch (err) {
    console.warn(`[youtube] title lookup failed for ${videoId}: ${err.message}`);
    return videoId;
  }
}