import { describe, expect, test } from 'bun:test';
import { providerFromNameservers, normaliseDomain, looksLikeDomain } from './dns';

/**
 * The pure half of the DNS check.
 *
 * `checkDomain` itself talks to a resolver and to a public-IP service, so a test of it would be a test of
 * this machine's network. What can actually be WRONG without anybody noticing is in here: which provider a
 * set of nameservers means, and what counts as a domain.
 */

describe('providerFromNameservers', () => {
  test('the common ones', () => {
    expect(providerFromNameservers(['ana.ns.cloudflare.com', 'bob.ns.cloudflare.com'])).toBe('cloudflare');
    expect(providerFromNameservers(['ns01.domaincontrol.com'])).toBe('godaddy');
    expect(providerFromNameservers(['ns-1234.awsdns.org'])).toBe('route53');
    expect(providerFromNameservers(['ns1.digitalocean.com'])).toBe('digitalocean');
  });

  test('a trailing dot and capitals, which is how resolvers actually answer', () => {
    expect(providerFromNameservers(['ANA.NS.CLOUDFLARE.COM.'])).toBe('cloudflare');
  });

  // `ns-cloud-a1.googledomains.com` ends with `google.com`? No — but `ns1.google.com` does, and a shorter
  // entry must not win over a longer one that also matches. Longest suffix, always.
  test('the longest matching suffix wins', () => {
    expect(providerFromNameservers(['ns-cloud-a1.googledomains.com'])).toBe('google');
  });

  test('an unrecognised nameserver is null rather than a guess', () => {
    expect(providerFromNameservers(['ns1.some-small-host.example'])).toBeNull();
    expect(providerFromNameservers([])).toBeNull();
  });
});

describe('normaliseDomain', () => {
  test('strips what people actually paste', () => {
    expect(normaliseDomain('  https://Officer.dev/some/path  ')).toBe('officer.dev');
    expect(normaliseDomain('officer.dev.')).toBe('officer.dev');
    expect(normaliseDomain('HTTP://OFFICER.DEV')).toBe('officer.dev');
  });
});

describe('looksLikeDomain', () => {
  test('accepts real ones, including a subdomain and a long TLD', () => {
    expect(looksLikeDomain('officer.dev')).toBe(true);
    expect(looksLikeDomain('sub.officer.dev')).toBe(true);
    expect(looksLikeDomain('a-b.example.museum')).toBe(true);
  });

  test('rejects the obvious nonsense, and leaves the rest to DNS', () => {
    expect(looksLikeDomain('officer')).toBe(false);
    expect(looksLikeDomain('-officer.dev')).toBe(false);
    expect(looksLikeDomain('officer .dev')).toBe(false);
    expect(looksLikeDomain('')).toBe(false);
  });
});