const INVALID_TEXT_VALUES = new Set(['-', 'null', 'undefined']);
const CERT_FIELD_KEYS = new Set([
  'certno',
  'personcertno',
  'othercertno',
  'selfcertno',
  'querycertno',
  'togethercertno',
  'livewithcertno',
  'objidcard',
  'idcard',
  'identitycode',
  'sfz',
]);

const normalizeSensitiveText = (value?: string | number | null) => {
  const text = String(value ?? '').trim();
  if (!text || INVALID_TEXT_VALUES.has(text.toLowerCase())) return '';
  return text;
};

export const isCertFieldKey = (value?: string | number | null) => {
  const text = normalizeSensitiveText(value);
  if (!text) return false;
  return CERT_FIELD_KEYS.has(text.replace(/[_-]/g, '').toLowerCase());
};

export const maskCertNo = (value?: string | number | null, keepStart = 4, keepEnd = 4) => {
  const text = normalizeSensitiveText(value);
  if (!text) return '-';
  if (text.length <= keepStart + keepEnd) return text;
  return `${text.slice(0, keepStart)}****${text.slice(-keepEnd)}`;
};