export function formatBytes(bytes) {
  if (bytes == null) return "";
  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(0)} KB`;
  if (bytes < 1024 * 1024 * 1024) return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
  return `${(bytes / (1024 * 1024 * 1024)).toFixed(2)} GB`;
}

export function formatElapsed(seconds) {
  if (seconds == null) return "";
  const s = Math.floor(seconds);
  const m = Math.floor(s / 60);
  const h = Math.floor(m / 60);
  const pad = (n) => String(n).padStart(2, "0");
  return h > 0 ? `${h}:${pad(m % 60)}:${pad(s % 60)}` : `${pad(m)}:${pad(s % 60)}`;
}

export function formatDuration(seconds) {
  if (seconds == null) return "—";
  if (seconds < 60) return `${seconds.toFixed(1)}s`;
  return formatElapsed(seconds);
}