// Example authentication middleware
import { NextFunction, Request, Response } from 'express';
import jwt from 'jsonwebtoken';

export const authenticate = (
  req: Request,
  res: Response,
  next: NextFunction
) => {
  const token = req.headers.authorization?.split(' ')[1];

  if (!token) {
    return res.status(401).json({ error: 'Authentication required' });
  }

  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET);
    req.user = decoded;
    next();
  } catch (error) {
    return res.status(401).json({ error: 'Invalid token' });
  }
};

// Example role-based authorization
export const authorize = (roles: string[]) => (
  req: Request,
  res: Response,
  next: NextFunction
) => {
  if (!req.user || !roles.includes(req.user.role)) {
    return res.status(403).json({ error: 'Access denied' });
  }
  next();
};

// Example data encryption
import crypto from 'crypto';

export const encrypt = (data: string): string => {
  const iv = crypto.randomBytes(16);
  const cipher = crypto.createCipheriv(
    'aes-256-gcm',
    process.env.ENCRYPTION_KEY,
    iv
  );
  let encrypted = cipher.update(data, 'utf8', 'hex');
  encrypted += cipher.final('hex');
  return `${iv.toString('hex')}:${encrypted}`;
};

// Example input validation
import { validate } from 'class-validator';

export const validateInput = async (data: any): Promise<ValidationError[]> => {
  const errors = await validate(data);
  return errors;
};

// Example input sanitization
import DOMPurify from 'dompurify';

export const sanitizeInput = (input: string): string => {
  return DOMPurify.sanitize(input);
};

// Example security headers
app.use(helmet());
app.use(cors({
  origin: process.env.ALLOWED_ORIGINS,
  methods: ['GET', 'POST', 'PUT', 'DELETE'],
  allowedHeaders: ['Content-Type', 'Authorization']
}));

// Example CSP configuration
app.use(helmet.contentSecurityPolicy({
  directives: {
    defaultSrc: ["'self'"],
    scriptSrc: ["'self'", "'unsafe-inline'"],
    styleSrc: ["'self'", "'unsafe-inline'"],
    imgSrc: ["'self'", "data:", "https:"],
    connectSrc: ["'self'"],
    fontSrc: ["'self'"],
    objectSrc: ["'none'"],
    mediaSrc: ["'self'"],
    frameSrc: ["'none'"]
  }
}));

// Example security logging
import winston from 'winston';

const logger = winston.createLogger({
  level: 'info',
  format: winston.format.json(),
  transports: [
    new winston.transports.File({ filename: 'security.log' })
  ]
});

export const logSecurityEvent = (event: SecurityEvent) => {
  logger.info('Security event', { event });
};

// Example security alerts
export const sendSecurityAlert = async (alert: SecurityAlert) => {
  await sendEmail({
    to: process.env.SECURITY_TEAM_EMAIL,
    subject: 'Security Alert',
    text: JSON.stringify(alert)
  });
};

// Example security checklist
const securityChecklist = [
  'Input validation',
  'Output encoding',
  'Authentication',
  'Authorization',
  'Data protection',
  'Error handling'
];

// Example security tests
describe('Security', () => {
  test('prevents SQL injection', async () => {
    const result = await query(`SELECT * FROM users WHERE id = ${userInput}`);
    expect(result).toBeEmpty();
  });
});

// Example incident detection
export const detectIncident = (event: SecurityEvent) => {
  if (isSecurityIncident(event)) {
    handleIncident(event);
  }
};

// Example incident response
export const handleIncident = async (incident: SecurityIncident) => {
  // Log incident
  logSecurityEvent(incident);

  // Notify team
  await sendSecurityAlert(incident);

  // Take action
  await takeRemedialAction(incident);
};