// SQLite datetime('now') 存的是 UTC "YYYY-MM-DD HH:MM:SS"，直接 new Date 会被当作本地时间。
function toDate(s: string): Date {
  const iso = /^\d{4}-\d{2}-\d{2} \d{2}:\d{2}(:\d{2})?$/.test(s)
    ? s.replace(" ", "T") + "Z"
    : s;
  return new Date(iso);
}

export function fmtTime(s: string | null | undefined): string {
  if (!s) return "-";
  const d = toDate(s);
  return isNaN(d.getTime()) ? s : d.toLocaleString();
}

export function fmtDuration(
  start: string | null | undefined,
  end: string | null | undefined
): string {
  if (!start) return "-";
  const a = toDate(start).getTime();
  if (isNaN(a)) return "-";
  const b = end ? toDate(end).getTime() : Date.now();
  if (isNaN(b)) return "-";
  let sec = Math.max(0, Math.round((b - a) / 1000));
  const h = Math.floor(sec / 3600);
  sec -= h * 3600;
  const m = Math.floor(sec / 60);
  sec -= m * 60;
  if (h > 0) return `${h}h ${m}m ${sec}s`;
  if (m > 0) return `${m}m ${sec}s`;
  return `${sec}s`;
}