/**
 * Smart timecode formatter.
 * Shows HH only if total duration >= 1 hour.
 * Shows MM only if total duration >= 1 minute.
 * Otherwise: SS:FF
 */
export function formatTimecode(s: number, fps: number = 30, totalDuration?: number): string {
  if (!s || isNaN(s)) return '00:00:00:00';
  const h = Math.floor(s / 3600);
  const m = Math.floor((s % 3600) / 60);
  const sec = Math.floor(s % 60);
  const f = Math.round(s * fps) % fps;

  // Determine minimum display based on total duration
  const total = totalDuration ?? s;
  const totalH = Math.floor(total / 3600);
  const totalM = Math.floor((total % 3600) / 60);

  if (totalH > 0) {
    // Video is 1h+: show HH:MM:SS:FF
    return `${String(h).padStart(2,'0')}:${String(m).padStart(2,'0')}:${String(sec).padStart(2,'0')}:${String(f).padStart(2,'0')}`;
  }
  if (totalM > 0) {
    // Video is 1m+: show MM:SS:FF
    return `${String(m).padStart(2,'0')}:${String(sec).padStart(2,'0')}:${String(f).padStart(2,'0')}`;
  }
  // Under 1m: show SS:FF
  return `${String(sec).padStart(2,'0')}:${String(f).padStart(2,'0')}`;
}