export function formatDateTime(dateTimeStr: string | null | undefined): string {
  if (!dateTimeStr) return '-';
  try {
    const date = new Date(dateTimeStr);
    if (isNaN(date.getTime())) return '-';
    const y = date.getFullYear();
    const m = String(date.getMonth() + 1).padStart(2, '0');
    const d = String(date.getDate()).padStart(2, '0');
    const h = String(date.getHours()).padStart(2, '0');
    const min = String(date.getMinutes()).padStart(2, '0');
    const s = String(date.getSeconds()).padStart(2, '0');
    return `${y}-${m}-${d} ${h}:${min}:${s}`;
  } catch {
    return '-';
  }
}

export function formatDateTimeShort(dateTimeStr: string | null | undefined): string {
  if (!dateTimeStr) return '-';
  try {
    const date = new Date(dateTimeStr);
    if (isNaN(date.getTime())) return '-';
    const m = String(date.getMonth() + 1).padStart(2, '0');
    const d = String(date.getDate()).padStart(2, '0');
    const h = String(date.getHours()).padStart(2, '0');
    const min = String(date.getMinutes()).padStart(2, '0');
    return `${m}/${d} ${h}:${min}`;
  } catch {
    return '-';
  }
}

export function formatDuration(ms: number | null | undefined): string {
  if (ms == null || ms < 0) return '-';
  const totalSeconds = Math.floor(ms / 1000);
  const hours = Math.floor(totalSeconds / 3600);
  const minutes = Math.floor((totalSeconds % 3600) / 60);
  const seconds = totalSeconds % 60;

  if (hours > 0) return `${hours}시간 ${minutes}분 ${seconds}초`;
  if (minutes > 0) return `${minutes}분 ${seconds}초`;
  return `${seconds}초`;
}

export function calculateDuration(
  startTime: string | null | undefined,
  endTime: string | null | undefined,
): string {
  if (!startTime) return '-';
  const start = new Date(startTime).getTime();
  if (isNaN(start)) return '-';

  if (!endTime) return '실행 중...';
  const end = new Date(endTime).getTime();
  if (isNaN(end)) return '-';

  return formatDuration(end - start);
}