export function normalizeMarketCountry(
  value: string | null | undefined
): string | null | undefined {
  const cleaned = typeof value === "string" ? value.trim() : undefined;
  if (!cleaned) {
    return undefined;
  }

  const normalized = cleaned.toUpperCase();
  if (!/^[A-Z]{2}$/.test(normalized)) {
    throw new Error(
      `Invalid marketCountry "${value}". Use an ISO 3166-1 alpha-2 uppercase country code such as "TH" or "DE".`
    );
  }

  return normalized;
}

export function isPlausibleEmail(value: string | null | undefined): boolean {
  if (!value) {
    return false;
  }

  return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(value);
}