const dateTimeFormatter = new Intl.DateTimeFormat('zh-CN', {
  year: 'numeric',
  month: '2-digit',
  day: '2-digit',
  hour: '2-digit',
  minute: '2-digit',
  second: '2-digit',
  hour12: false,
});

const relativeTimeFormatter = new Intl.RelativeTimeFormat('zh-CN', {
  numeric: 'auto',
});

function toDate(value: string | Date | null | undefined) {
  if (!value) {
    return null;
  }

  const normalizedValue =
    typeof value === 'string' ? value.replace(' ', 'T') : value;
  const date =
    normalizedValue instanceof Date
      ? normalizedValue
      : new Date(normalizedValue);
  return Number.isNaN(date.getTime()) ? null : date;
}

export function formatDateTime(value: string | Date | null | undefined) {
  const date = toDate(value);

  if (!date) {
    return '—';
  }

  return dateTimeFormatter.format(date).replace(/\//g, '-');
}

export function formatRelativeTime(value: string | Date | null | undefined) {
  const date = toDate(value);

  if (!date) {
    return '—';
  }

  const diffMs = date.getTime() - Date.now();
  const diffSeconds = Math.round(diffMs / 1000);
  const absSeconds = Math.abs(diffSeconds);

  if (absSeconds < 60) {
    return relativeTimeFormatter.format(diffSeconds, 'second');
  }

  const diffMinutes = Math.round(diffSeconds / 60);
  if (Math.abs(diffMinutes) < 60) {
    return relativeTimeFormatter.format(diffMinutes, 'minute');
  }

  const diffHours = Math.round(diffMinutes / 60);
  if (Math.abs(diffHours) < 24) {
    return relativeTimeFormatter.format(diffHours, 'hour');
  }

  const diffDays = Math.round(diffHours / 24);
  if (Math.abs(diffDays) < 30) {
    return relativeTimeFormatter.format(diffDays, 'day');
  }

  const diffMonths = Math.round(diffDays / 30);
  if (Math.abs(diffMonths) < 12) {
    return relativeTimeFormatter.format(diffMonths, 'month');
  }

  const diffYears = Math.round(diffMonths / 12);
  return relativeTimeFormatter.format(diffYears, 'year');
}