/**
 * Runbook section 2 — the public endpoint and its TLS identity.
 *
 * CAP-003 public DNS resolves to every node
 * CAP-004 TLS identity is correct and not near expiry
 *
 * The certificate is inspected through a real validated handshake rather than
 * by reading the cert-manager Certificate object. A Certificate resource can
 * report Ready while Traefik serves a stale or default certificate — the only
 * claim that matters is what an external client is actually handed.
 */

import { resolve4 } from 'node:dns/promises';
import { connect, type PeerCertificate } from 'node:tls';
import { expect, test } from '@playwright/test';
import { recordJson } from '../support/evidence';
import { EXPECTED_NODE_IPS, PUBLIC_BASE_URL, PUBLIC_HOST } from '../support/env';

/** Minimum remaining certificate validity before this is a finding. */
const MIN_CERT_DAYS = 30;

type CertificateFacts = {
  subjectCN: string;
  issuer: string;
  validTo: string;
  daysRemaining: number;
  subjectAltName?: string;
  authorized: boolean;
  protocol: string | null;
};

/**
 * Complete a validated TLS handshake against one node IP with SNI set, and
 * report what the peer presented.
 *
 * Connecting by IP with an explicit servername is deliberate: it proves the
 * certificate is correct on *that specific node* rather than on whichever node
 * DNS happened to return, which is how a partially-deployed certificate hides.
 */
async function inspectCertificate(host: string): Promise<CertificateFacts> {
  const { promise, resolve, reject } = Promise.withResolvers<CertificateFacts>();

  const socket = connect({
    host,
    port: 443,
    servername: PUBLIC_HOST,
    rejectUnauthorized: true,
    timeout: 15_000,
  });

  socket.once('secureConnect', () => {
    const certificate: PeerCertificate = socket.getPeerCertificate();
    const validTo = new Date(certificate.valid_to);
    // X.509 RDNs can legitimately repeat, so Node types these as
    // `string | string[]`. Take the first value rather than stringifying an
    // array into the assertion message.
    const first = (value: string | string[] | undefined): string =>
      Array.isArray(value) ? (value[0] ?? '') : (value ?? '');
    resolve({
      subjectCN: first(certificate.subject?.CN),
      issuer: [first(certificate.issuer?.O), first(certificate.issuer?.CN)]
        .filter(Boolean)
        .join(' '),
      validTo: validTo.toISOString(),
      daysRemaining: Math.floor((validTo.getTime() - Date.now()) / 86_400_000),
      subjectAltName: certificate.subjectaltname,
      authorized: socket.authorized,
      protocol: socket.getProtocol(),
    });
    socket.end();
  });
  socket.once('timeout', () => {
    socket.destroy();
    reject(new Error(`TLS handshake to ${host} timed out`));
  });
  socket.once('error', (error) => reject(error));

  return promise;
}

test.describe('section 2 — public endpoint and TLS', () => {
  test('the public hostname resolves to every node IP', async ({}, testInfo) => {
    const addresses = await resolve4(PUBLIC_HOST);
    await recordJson(testInfo, 'dns-a-records', {
      host: PUBLIC_HOST,
      resolved: [...addresses].sort(),
      expected: [...EXPECTED_NODE_IPS].sort(),
    });

    // A missing record silently concentrates traffic; an extra record points
    // somewhere undocumented. Assert the exact set.
    expect([...addresses].sort(), 'A records must match the known node set').toEqual(
      [...EXPECTED_NODE_IPS].sort(),
    );
  });

  test('every node presents a valid, correctly-named, unexpired certificate', async ({}, testInfo) => {
    const facts: Record<string, CertificateFacts> = {};

    for (const ip of EXPECTED_NODE_IPS) {
      facts[ip] = await test.step(`TLS handshake to ${ip}`, () => inspectCertificate(ip));
    }
    await recordJson(testInfo, 'tls-certificates', facts);

    for (const [ip, certificate] of Object.entries(facts)) {
      // rejectUnauthorized was true, so reaching here already proves the chain
      // validated. Assert it explicitly so the intent survives a refactor.
      expect(certificate.authorized, `${ip} chain must validate`).toBe(true);
      expect(certificate.subjectCN, `${ip} certificate CN`).toBe(PUBLIC_HOST);
      expect(certificate.issuer, `${ip} issuer should be Let's Encrypt`).toContain(
        "Let's Encrypt",
      );
      expect(certificate.subjectAltName, `${ip} SAN must cover the hostname`).toContain(
        PUBLIC_HOST,
      );
      expect(
        certificate.daysRemaining,
        `${ip} certificate expires in ${certificate.daysRemaining}d — renewal is overdue`,
      ).toBeGreaterThan(MIN_CERT_DAYS);
      expect(certificate.protocol, `${ip} should negotiate modern TLS`).toMatch(
        /TLSv1\.[23]/,
      );
    }

    // All three nodes are fronted by the same Traefik and must present the same
    // certificate. A divergence means one node did not pick up a renewal.
    const distinctExpiries = [
      ...new Set(Object.values(facts).map((certificate) => certificate.validTo)),
    ];
    expect(
      distinctExpiries,
      'every node must serve the same certificate generation',
    ).toHaveLength(1);
  });

  test('health is publicly reachable without a credential', async ({
    playwright,
  }, testInfo) => {
    const context = await playwright.request.newContext({ ignoreHTTPSErrors: false });
    try {
      const response = await context.get(`${PUBLIC_BASE_URL}/health`);
      const body = await response.text();
      await recordJson(testInfo, 'health', { status: response.status(), body: body.slice(0, 300) });

      // /health is intentionally open — it is what the probes and the uptime
      // monitor call. It must not require the bearer.
      expect(response.status(), '/health must be open and 200').toBe(200);
    } finally {
      await context.dispose();
    }
  });
});