/**
 * South African phone number utilities (mirrors backend/src/utils/whatsapp.js logic).
 */

/**
 * Normalise a raw phone input to the international SA format (27XXXXXXXXX).
 * Returns null if the input is not a valid SA mobile number.
 */
export function normalizeZAPhone(raw: string | null | undefined): string | null {
  if (!raw) return null;
  let digits = raw.replace(/\D/g, '');
  if (digits.startsWith('0') && digits.length === 10) digits = '27' + digits.slice(1);
  if (/^27\d{9}$/.test(digits)) return digits;
  return null;
}

/**
 * Returns true when the value is a valid SA mobile number (any common format).
 */
export function isValidZAPhone(raw: string | null | undefined): boolean {
  return normalizeZAPhone(raw) !== null;
}