const express = require('express');
const dotenv = require('dotenv');
const cors = require('cors');
const morgan = require('morgan');
const { connectDB } = require('./config/db');
const { errorHandler } = require('./middleware/errorHandler');
const routes = require('./routes');
const logger = require('./utils/logger');

// 加载环境变量
dotenv.config();

// 验证关键环境变量
const requiredEnvVars = ['MONGODB_URI', 'JWT_SECRET', 'ADMIN_USERNAME', 'ADMIN_PASSWORD'];
const missingEnvVars = requiredEnvVars.filter(envVar => !process.env[envVar]);

if (missingEnvVars.length > 0) {
  logger.error(`缺少必要的环境变量: ${missingEnvVars.join(', ')}`);
  process.exit(1);
}

logger.info('环境变量加载成功');
logger.info(`NODE_ENV: ${process.env.NODE_ENV}`);
logger.info(`ADMIN_USERNAME: ${process.env.ADMIN_USERNAME}`);
logger.info(`JWT_SECRET: ${process.env.JWT_SECRET ? '已设置' : '未设置'}`);

// 初始化 Express 应用
const app = express();

// 中间件
app.use(cors());
app.use(express.json({ limit: '50mb' }));
app.use(express.urlencoded({ extended: true, limit: '50mb' }));
// 日志中间件
if (process.env.NODE_ENV === 'development') {
  app.use(morgan('dev'));
}

// 连接数据库
connectDB();

// 路由
app.use('/api', routes);

// 健康检查端点
app.get('/health', (req, res) => {
  res.status(200).json({ status: 'ok', message: 'Server is running' });
});

// 错误处理中间件
app.use(errorHandler);

// 启动服务器
const PORT = process.env.PORT || 8080;
app.listen(PORT, () => {
  logger.info(`Server running in ${process.env.NODE_ENV} mode on port ${PORT}`);
});

// 处理未捕获的异常
process.on('uncaughtException', (err) => {
  logger.error('Uncaught Exception:', err);
  process.exit(1);
});

// 处理未处理的 Promise 拒绝
process.on('unhandledRejection', (err) => {
  logger.error('Unhandled Rejection:', err);
  process.exit(1);
});