/**
 * Phone numbers reach us in every shape the UI allows — `+251912345678`, `0912345678`,
 * `912345678`, and the same again with spaces or dashes. Comparing two of them as raw strings
 * is a coin flip, so anything that decides access on a phone number must normalise first.
 *
 * Mirrors `PassengerAuthService.standardizePhone`, plus the bare-9-digit case the passenger
 * form produces (its input sits behind a fixed `+251` prefix control).
 */
export function normalizePhone(phone?: string | null): string | null {
  if (!phone) return null;
  const digits = phone.replace(/\D/g, '');
  if (!digits) return null;
  if (digits.startsWith('251')) return `+${digits}`;
  if (digits.startsWith('0')) return `+251${digits.slice(1)}`;
  // A bare local subscriber number, e.g. "912345678" from the +251-prefixed input.
  if (digits.length === 9) return `+251${digits}`;
  return `+${digits}`;
}

/** True only when both numbers are present and resolve to the same E.164 form. */
export function samePhone(a?: string | null, b?: string | null): boolean {
  const left = normalizePhone(a);
  const right = normalizePhone(b);
  return !!left && !!right && left === right;
}