const jwt = require('jsonwebtoken');
const { AppError } = require('./errorHandler');

const JWT_SECRET = process.env.JWT_SECRET;

if (!JWT_SECRET && process.env.NODE_ENV === 'production') {
  throw new Error('JWT_SECRET must be set in production');
}

const tokenSecret = JWT_SECRET || 'accountbook_secret_key_2024';

function authenticate(req, res, next) {
  const token = req.headers.authorization?.split(' ')[1];
  if (!token) {
    throw new AppError('请先登录', 401, 'UNAUTHORIZED');
  }

  try {
    const decoded = jwt.verify(token, tokenSecret);
    req.userId = decoded.userId;
    next();
  } catch (err) {
    throw new AppError('登录已过期', 401, 'TOKEN_EXPIRED');
  }
}

function generateToken(userId) {
  return jwt.sign({ userId }, tokenSecret, { expiresIn: '7d' });
}

module.exports = {
  authenticate,
  generateToken,
  JWT_SECRET: tokenSecret,
};