function formatDateTime(iso) {
  if (!iso || typeof iso !== 'string') return '-';
  // expected format: 2026-03-30T12:34:56
  const s = iso.replace('T', ' ').replace('Z', '');
  if (s.length > 19) return s.slice(0, 19);
  return s;
}

function formatTime(iso) {
  if (!iso || typeof iso !== 'string') return '-';
  const s = iso.replace('T', ' ').replace('Z', '');
  // 返回 yyyy-MM-dd HH:mm 格式
  if (s.length >= 16) return s.slice(0, 16);
  return s;
}

function eventStatusText(status) {
  // 与后端 EventStatus 枚举一致
  const strMap = {
    NotStarted: '未开始',
    Enrolling: '报名中',
    RegistrationEnded: '报名结束',
    Ongoing: '比赛中',
    Ended: '已结束'
  };
  if (strMap[status] != null) return strMap[status];

  const n = status === undefined || status === null || status === '' ? NaN : Number(status);
  const numMap = {
    0: '未开始',
    1: '报名中',
    2: '报名结束',
    3: '比赛中',
    4: '已结束'
  };
  if (!Number.isNaN(n) && numMap[n] !== undefined) return numMap[n];
  return status !== undefined && status !== null && status !== '' ? `状态${status}` : '';
}

/** 列表角标样式用：0~4，未知时回退 0 */
function eventStatusForPill(status) {
  const strToNum = {
    NotStarted: 0,
    Enrolling: 1,
    RegistrationEnded: 2,
    Ongoing: 3,
    Ended: 4
  };
  if (strToNum[status] !== undefined) return strToNum[status];
  const n = Number(status);
  if (!Number.isNaN(n) && n >= 0 && n <= 4) return n;
  return 0;
}

function eventFormatText(v) {
  if (v === 'Offline') return '线下';
  if (v === 'Online') return '线上';
  return '';
}

module.exports = {
  formatDateTime,
  formatTime,
  eventStatusText,
  eventStatusForPill,
  eventFormatText
};