export type DomainAgeResult = {
  domain: string;
  registeredAt: string | null;
  ageDays: number | null;
  source: 'rdap' | 'unavailable';
};

type RdapEvent = { eventAction?: string; eventDate?: string };

async function fetchRdap(domain: string): Promise<DomainAgeResult> {
  const response = await fetch(`https://rdap.org/domain/${encodeURIComponent(domain)}`, {
    headers: { Accept: 'application/rdap+json' },
  });

  if (!response.ok) {
    return { domain, registeredAt: null, ageDays: null, source: 'unavailable' };
  }

  const data = (await response.json()) as { events?: RdapEvent[] };
  const registration = data.events?.find((event) => event.eventAction === 'registration');

  if (!registration?.eventDate) {
    return { domain, registeredAt: null, ageDays: null, source: 'unavailable' };
  }

  const registeredAt = new Date(registration.eventDate);
  if (Number.isNaN(registeredAt.getTime())) {
    return { domain, registeredAt: null, ageDays: null, source: 'unavailable' };
  }

  const ageDays = Math.floor((Date.now() - registeredAt.getTime()) / (1000 * 60 * 60 * 24));

  return {
    domain,
    registeredAt: registeredAt.toISOString(),
    ageDays,
    source: 'rdap',
  };
}

export async function checkDomainAge(emailOrDomain: string): Promise<DomainAgeResult> {
  const domain = emailOrDomain.includes('@')
    ? emailOrDomain.split('@')[1]!.toLowerCase()
    : emailOrDomain.toLowerCase();

  return fetchRdap(domain);
}