/** Format seconds to mm:ss (for playback time display) */
export function formatTime(seconds: number): string {
  if (!isFinite(seconds) || seconds < 0) return '0:00'
  const m = Math.floor(seconds / 60)
  const s = Math.floor(seconds % 60)
  return `${m}:${s.toString().padStart(2, '0')}`
}

/** Format seconds to mm:ss, returns '--:--' for invalid/zero values (for track duration display) */
export function formatDuration(seconds: number): string {
  if (!seconds || !isFinite(seconds) || seconds <= 0) return '--:--'
  const m = Math.floor(seconds / 60)
  const s = Math.floor(seconds % 60)
  return `${m}:${s.toString().padStart(2, '0')}`
}