backend/src/utils/logger.js

import winston from 'winston';
import path from 'path';
import { fileURLToPath } from 'url';
import fs from 'fs';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

// 确保日志目录存在
const logDir = path.join(__dirname, '../../logs');
if (!fs.existsSync(logDir)) {
  fs.mkdirSync(logDir, { recursive: true });
}

// 自定义日志格式
const logFormat = winston.format.combine(
  winston.format.timestamp({
    format: 'YYYY-MM-DD HH:mm:ss'
  }),
  winston.format.errors({ stack: true }),
  winston.format.printf(({ level, message, timestamp, stack }) => {
    if (stack) {
      return `${timestamp} [${level.toUpperCase()}]: ${message}\n${stack}`;
    }
    return `${timestamp} [${level.toUpperCase()}]: ${message}`;
  })
);

// 创建logger实例
const logger = winston.createLogger({
  level: process.env.LOG_LEVEL || 'info',
  format: logFormat,
  transports: [
    // 控制台输出
    new winston.transports.Console({
      format: winston.format.combine(
        winston.format.colorize(),
        logFormat
      )
    }),
    
    // 错误日志文件
    new winston.transports.File({
      filename: path.join(logDir, 'error.log'),
      level: 'error',
      maxsize: 5242880, // 5MB
      maxFiles: 5
    }),
    
    // 综合日志文件
    new winston.transports.File({
      filename: path.join(logDir, 'combined.log'),
      maxsize: 5242880, // 5MB
      maxFiles: 5
    })
  ],
  
  // 处理未捕获的异常
  exceptionHandlers: [
    new winston.transports.File({
      filename: path.join(logDir, 'exceptions.log')
    })
  ],
  
  // 处理未处理的Promise拒绝
  rejectionHandlers: [
    new winston.transports.File({
      filename: path.join(logDir, 'rejections.log')
    })
  ]
});

// 在生产环境中不输出到控制台
if (process.env.NODE_ENV === 'production') {
  logger.remove(logger.transports[0]); // 移除控制台传输
}

// 添加请求日志中间件
export const requestLogger = (req, res, next) => {
  const start = Date.now();
  
  res.on('finish', () => {
    const duration = Date.now() - start;
    const logData = {
      method: req.method,
      url: req.url,
      status: res.statusCode,
      duration: `${duration}ms`,
      ip: req.ip || req.connection.remoteAddress,
      userAgent: req.get('User-Agent')
    };
    
    if (res.statusCode >= 400) {
      logger.warn(`HTTP ${res.statusCode} - ${JSON.stringify(logData)}`);
    } else {
      logger.info(`HTTP ${res.statusCode} - ${JSON.stringify(logData)}`);
    }
  });
  
  next();
};

export default logger;