Trek_CN/server/src/config.ts

import crypto from 'crypto';
import fs from 'fs';
import path from 'path';

const dataDir = path.resolve(__dirname, '../data');

// JWT_SECRET is always managed by the server — auto-generated on first start and
// persisted to data/.jwt_secret. Use the admin panel to rotate it; do not set it
// via environment variable (env var would override a rotation on next restart).
const jwtSecretFile = path.join(dataDir, '.jwt_secret');
let _jwtSecret: string;

try {
  _jwtSecret = fs.readFileSync(jwtSecretFile, 'utf8').trim();
} catch {
  _jwtSecret = crypto.randomBytes(32).toString('hex');
  try {
    if (!fs.existsSync(dataDir)) fs.mkdirSync(dataDir, { recursive: true });
    fs.writeFileSync(jwtSecretFile, _jwtSecret, { mode: 0o600 });
    console.log('Generated and saved JWT secret to', jwtSecretFile);
  } catch (writeErr: unknown) {
    console.warn('WARNING: Could not persist JWT secret to disk:', writeErr instanceof Error ? writeErr.message : writeErr);
    console.warn('Sessions will reset on server restart.');
  }
}

// export let so TypeScript's CJS output keeps exports.JWT_SECRET live
// (generates `exports.JWT_SECRET = JWT_SECRET = newVal` inside updateJwtSecret)
export let JWT_SECRET = _jwtSecret;

// Called by the admin rotate-jwt-secret endpoint to update the in-process
// binding that all middleware and route files reference.
export function updateJwtSecret(newSecret: string): void {
  JWT_SECRET = newSecret;
}

// ENCRYPTION_KEY is used to derive at-rest encryption keys for stored secrets
// (API keys, MFA TOTP secrets, SMTP password, OIDC client secret, etc.).
// Keeping it separate from JWT_SECRET means you can rotate session tokens without
// invalidating all stored encrypted data, and vice-versa.
//
// Upgrade note: if you already have encrypted data stored under a previous build
// that used JWT_SECRET for encryption, set ENCRYPTION_KEY to the value of your
// old JWT_SECRET so existing encrypted values continue to decrypt correctly.
// After re-saving all credentials via the admin panel you can switch to a new
// random ENCRYPTION_KEY.
const ENCRYPTION_KEY: string = process.env.ENCRYPTION_KEY || '';

if (!ENCRYPTION_KEY) {
  console.error('FATAL: ENCRYPTION_KEY is not set.');
  console.error('If this occurs after an update, set ENCRYPTION_KEY to the value of your old JWT secret.');
  console.error('Your JWT secret is stored in data/.jwt_secret (host path: ./data/.jwt_secret).');
  console.error('For a fresh install, generate a random key: openssl rand -hex 32');
  process.exit(1);
}

export { ENCRYPTION_KEY };