import { BadRequestException } from '@nestjs/common';
import { assertPublicWebhookUrl } from './webhook-url-guard';

function lookupResolving(...addresses: string[]) {
  return () =>
    Promise.resolve(addresses.map((address) => ({ address, family: 4 })));
}

function lookupFailing() {
  return () => Promise.reject(new Error('ENOTFOUND'));
}

describe('assertPublicWebhookUrl', () => {
  it('accepts a hostname that resolves only to public addresses', async () => {
    await expect(
      assertPublicWebhookUrl(
        'https://example.com/hook',
        lookupResolving('93.184.216.34'),
      ),
    ).resolves.toBeUndefined();
  });

  it('rejects an invalid URL', async () => {
    await expect(assertPublicWebhookUrl('not-a-url')).rejects.toBeInstanceOf(
      BadRequestException,
    );
  });

  it('rejects non-http(s) schemes', async () => {
    await expect(
      assertPublicWebhookUrl('ftp://example.com/hook'),
    ).rejects.toBeInstanceOf(BadRequestException);
    await expect(
      assertPublicWebhookUrl('file:///etc/passwd'),
    ).rejects.toBeInstanceOf(BadRequestException);
  });

  it('rejects localhost by hostname', async () => {
    await expect(
      assertPublicWebhookUrl('http://localhost/hook'),
    ).rejects.toBeInstanceOf(BadRequestException);
  });

  it('rejects IPv4 loopback and its shorthand/decimal/hex/octal encodings', async () => {
    for (const url of [
      'http://127.0.0.1/hook',
      'http://127.1/hook',
      'http://0x7f000001/hook',
      'http://2130706433/hook',
      'http://017700000001/hook',
    ]) {
      await expect(assertPublicWebhookUrl(url)).rejects.toBeInstanceOf(
        BadRequestException,
      );
    }
  });

  it('rejects RFC 1918 private ranges', async () => {
    for (const url of [
      'http://10.0.0.5/hook',
      'http://172.16.0.5/hook',
      'http://172.31.255.255/hook',
      'http://192.168.1.1/hook',
    ]) {
      await expect(assertPublicWebhookUrl(url)).rejects.toBeInstanceOf(
        BadRequestException,
      );
    }
  });

  it('rejects link-local addresses including the cloud metadata endpoint', async () => {
    await expect(
      assertPublicWebhookUrl('http://169.254.169.254/latest/meta-data/'),
    ).rejects.toBeInstanceOf(BadRequestException);
  });

  it('does not reject a public IPv4 literal outside reserved ranges', async () => {
    await expect(
      assertPublicWebhookUrl('http://8.8.8.8/hook'),
    ).resolves.toBeUndefined();
  });

  it('rejects IPv6 loopback and link-local addresses', async () => {
    await expect(
      assertPublicWebhookUrl('http://[::1]/hook'),
    ).rejects.toBeInstanceOf(BadRequestException);
    await expect(
      assertPublicWebhookUrl('http://[fe80::1]/hook'),
    ).rejects.toBeInstanceOf(BadRequestException);
  });

  it('rejects a hostname that resolves to a private address (DNS-based bypass)', async () => {
    await expect(
      assertPublicWebhookUrl(
        'https://attacker.example/hook',
        lookupResolving('10.0.0.5'),
      ),
    ).rejects.toBeInstanceOf(BadRequestException);
  });

  it('rejects a hostname that resolves to the cloud metadata address', async () => {
    await expect(
      assertPublicWebhookUrl(
        'https://attacker.example/hook',
        lookupResolving('169.254.169.254'),
      ),
    ).rejects.toBeInstanceOf(BadRequestException);
  });

  it('rejects a hostname where any resolved address is private, even if others are public', async () => {
    await expect(
      assertPublicWebhookUrl(
        'https://attacker.example/hook',
        lookupResolving('93.184.216.34', '10.0.0.5'),
      ),
    ).rejects.toBeInstanceOf(BadRequestException);
  });

  it('rejects a hostname that fails to resolve', async () => {
    await expect(
      assertPublicWebhookUrl(
        'https://does-not-exist.invalid/hook',
        lookupFailing(),
      ),
    ).rejects.toBeInstanceOf(BadRequestException);
  });
});