export function maskDateBR(input: string) {
  const digits = input.replace(/\D/g, '').slice(0, 8);
  const parts: string[] = [];
  if (digits.length > 0) parts.push(digits.slice(0, 2));
  if (digits.length > 2) parts.push(digits.slice(2, 4));
  if (digits.length > 4) parts.push(digits.slice(4, 8));
  return parts.join('/');
}

export function isValidDateBR(value: string) {
  const m = value.match(/^(\d{2})\/(\d{2})\/(\d{4})$/);
  if (!m) return false;
  const [, dd, mm, yyyy] = m.map(Number) as unknown as [string, number, number, number];
  const d = new Date(yyyy, mm - 1, dd);
  return d.getFullYear() === yyyy && d.getMonth() === mm - 1 && d.getDate() === dd;
}

export function brToISO(value: string): string | null {
  if (!isValidDateBR(value)) return null;
  const [dd, mm, yyyy] = value.split('/');
  return `${yyyy}-${mm}-${dd}`;
}