// ============================================================
// SIGN-IN CODES
// ============================================================
// A code emailed to you, offered beside the password rather than instead of it.
// The rules here are what keep it from being a second, weaker front door.

const test = require('node:test');
const assert = require('node:assert');
const fs = require('fs');
const path = require('path');
const lc = require('../src/utils/loginCodes');
const read = p => fs.readFileSync(path.join(__dirname, '..', p), 'utf8');

test('codes are six digits and uniformly drawn', () => {
  const seen = new Set();
  for (let i = 0; i < 3000; i++) {
    const code = lc.generate();
    assert.match(code, /^\d{6}$/);
    seen.add(code);
  }
  // Rejection sampling, not modulo on a random byte, which would make low
  // digits likelier.
  assert.match(read('src/utils/loginCodes.js'), /while \(value >= Math\.floor\(0xFFFFFFFF \/ max\) \* max\)/);
  assert.ok(seen.size > 2800, 'not repeating itself');
  assert.equal(lc.normalise(' 12 34-56 '), '123456');
});

test('a code is stored as a hash, used once, and superseded by the next', () => {
  const src = read('src/utils/loginCodes.js');
  // A code read out of the database must not be a working credential.
  assert.match(src, /bcrypt\.hash\(code, 10\)/);
  // The value bound to code_hash is the hash, never the code itself.
  assert.match(src, /\[userId, await bcrypt\.hash\(code, 10\)\]/);
  assert.doesNotMatch(src, /\[userId, code\]/, 'the plaintext is never inserted');
  // Asking for a new one must not leave the old one working.
  assert.match(src, /DELETE FROM login_codes WHERE user_id = \?/);
  // Marked used before a session is issued, so a replay cannot race it.
  assert.match(src, /UPDATE login_codes SET used_at = NOW\(\) WHERE id = \? AND used_at IS NULL RETURNING id/);
  assert.match(src, /expires_at > NOW\(\)/);
  assert.match(src, /row\.attempts >= MAX_ATTEMPTS/);
  assert.equal(lc.MAX_ATTEMPTS, 5);
  assert.equal(lc.TTL_MINUTES, 10);
});

test('neither endpoint says whether an account exists', () => {
  const route = read('src/routes/auth.js');
  // A sign-in screen that answers "no such account" is a way of finding out who
  // has one, which is worth more to an attacker than the code is.
  assert.match(route, /var GENERIC = \{ success: true, message: 'If that account exists, a code is on its way\.' \};/);
  assert.match(route, /if \(!user \|\| user\.disabled\) \{\s*\n\s*console\.warn\('\[Auth\] login-code: no deliverable account/);
  // One refusal for every failure on verify, too.
  assert.match(route, /var REFUSED = \{ error: 'That code is not valid\./);
  // A code proves you can read the mailbox. An account that asked for a second
  // factor still wants it.
  assert.match(route, /if \(user\.totp_enabled\) \{\s*\n\s*if \(!totpCode\) return res\.json\(\{ requires2FA: true \}\);/);
});

test('the new endpoints are rate limited, and reachable while signed out', () => {
  const server = read('server.js');
  // Express matches app.use paths on segment boundaries, so the /api/auth/login
  // limiter does not cover /api/auth/login-code — verified against a real
  // router, not assumed.
  assert.match(server, /app\.use\('\/api\/auth\/login-code\/request', rateLimit\(\{/);
  assert.match(server, /app\.use\('\/api\/auth\/login-code\/verify', rateLimit\(\{/);
  // Asking for a code sends mail to someone else's address, so it is limited
  // more tightly than an attempt to sign in.
  assert.match(server, /LOGIN_CODE_RATE_LIMIT_MAX \|\| '5'/);

  // authFetch rejects any /api path not on its allowlist before it is sent,
  // which surfaced as "Connection error" with no request leaving the browser.
  const wrapper = read('public/js/authFetch.js');
  assert.match(wrapper, /'\/api\/auth\/login-code\/request', '\/api\/auth\/login-code\/verify'/);
  assert.match(wrapper, /url\.pathname === '\/api\/auth\/login-code\/verify'/, 'and it counts as a login');
});

test('the screen asks for the email first and always offers both ways in', () => {
  const html = read('public/index.html');
  assert.match(html, /id="btn-login-continue"/);
  assert.match(html, /id="btn-login-send-code"/);
  assert.match(html, /id="btn-login-use-password"/);
  assert.match(html, /id="login-change-email"/);
  // Creating an account stays on the first step.
  assert.match(html, /id="show-register"/);

  const js = read('public/js/auth.js');
  // A code needs mail to arrive and a password does not, so the password option
  // sits beside the code option rather than behind it.
  assert.match(js, /reveal\('login-choice', step === 'choice'\)/);
  assert.match(js, /loginMode === 'code' \? submitCode : submitLogin/);
  // classList, not a string replace: hiding twice appended 'hidden' twice and a
  // non-global replace stripped only one, so the element stayed hidden forever.
  assert.match(js, /if \(on\) el\.classList\.remove\('hidden'\); else el\.classList\.add\('hidden'\);/);
  // One response handler, so a code sign-in gets the same 2FA prompt and the
  // same welcome as a password one.
  assert.match(js, /function handleSignIn\(data, attempt\)/);
});