// Date formatting for the Headscale views. The sidecar already turned protobuf's zero timestamp into null,
// so null genuinely means "never" here and every helper says so rather than printing a fake date.

export function timeAgo(iso: string | null): string {
  if (!iso) return 'never';
  const seconds = Math.round((Date.now() - new Date(iso).getTime()) / 1000);
  if (!Number.isFinite(seconds)) return 'unknown';
  if (seconds < 0) return 'just now';
  if (seconds < 60) return 'just now';
  const minutes = Math.round(seconds / 60);
  if (minutes < 60) return `${minutes}m ago`;
  const hours = Math.round(minutes / 60);
  if (hours < 24) return `${hours}h ago`;
  const days = Math.round(hours / 24);
  if (days < 365) return `${days}d ago`;
  return `${Math.round(days / 365)}y ago`;
}

/** "in 3d" / "5h ago" — signed, for expiry dates that may be either side of now. */
export function timeUntil(iso: string | null): string {
  if (!iso) return 'never';
  const seconds = Math.round((new Date(iso).getTime() - Date.now()) / 1000);
  if (!Number.isFinite(seconds)) return 'unknown';
  if (seconds < 0) return timeAgo(iso);
  const minutes = Math.round(seconds / 60);
  if (minutes < 60) return `in ${Math.max(1, minutes)}m`;
  const hours = Math.round(minutes / 60);
  if (hours < 24) return `in ${hours}h`;
  return `in ${Math.round(hours / 24)}d`;
}

export function fullDate(iso: string | null): string {
  if (!iso) return 'never';
  return new Date(iso).toLocaleString();
}