const express = require('express');
const cors = require('cors');
const helmet = require('helmet');
const dotenv = require('dotenv');
const rateLimit = require('express-rate-limit');
const mysql = require('mysql2/promise');
const path = require('path');

// 导入路由模块
const authModule = require('./routes/auth');
const usersModule = require('./routes/users');
const cattleModule = require('./routes/cattle');
const financeModule = require('./routes/finance');
const tradingModule = require('./routes/trading');
const governmentModule = require('./routes/government');
const mallModule = require('./routes/mall');

// 加载环境变量
dotenv.config();

// 数据库连接
let pool, testDatabaseConnection;

if (process.env.DB_TYPE === 'sqlite') {
  // 使用SQLite
  const sqliteDb = require('./database-sqlite');
  pool = sqliteDb.pool;
  testDatabaseConnection = sqliteDb.testDatabaseConnection;
} else {
  // 使用MySQL
  const mysql = require('mysql2/promise');
  
  // 数据库连接配置
  const dbConfig = {
    host: process.env.DB_HOST,
    port: process.env.DB_PORT,
    user: process.env.DB_USER,
    password: process.env.DB_PASSWORD,
    database: process.env.DB_NAME,
    charset: process.env.DB_CHARSET || 'utf8mb4',
    connectionLimit: 10,
    acquireTimeout: 60000,
    timeout: 60000
  };

  // 创建数据库连接池
  pool = mysql.createPool(dbConfig);

  // 测试数据库连接
  testDatabaseConnection = async function() {
    try {
      const connection = await pool.getConnection();
      console.log('✅ MySQL数据库连接成功');
      console.log(`📍 连接到: ${process.env.DB_HOST}:${process.env.DB_PORT}/${process.env.DB_NAME}`);
      connection.release();
      return true;
    } catch (error) {
      console.error('❌ 数据库连接失败:', error.message);
      console.log('⚠️  服务将继续运行，但数据库功能不可用');
      return false;
    }
  };
}

// 创建Express应用
const app = express();
const PORT = process.env.PORT || 8888;

// 初始化数据库和中间件的异步函数
async function initializeApp() {
  // 启动时测试数据库连接
  await testDatabaseConnection();
  
  // 设置路由模块的数据库连接
  authModule.setPool(pool);
  usersModule.setMiddleware(authModule.authenticateToken, authModule.checkPermission, pool);
  cattleModule.setMiddleware(authModule.authenticateToken, authModule.checkPermission, pool);
  financeModule.setMiddleware(authModule.authenticateToken, authModule.checkPermission, pool);
  tradingModule.setMiddleware(authModule.authenticateToken, authModule.checkPermission, pool);
  governmentModule.setMiddleware(authModule.authenticateToken, authModule.checkPermission, pool);
  mallModule.setMiddleware(authModule.authenticateToken, authModule.checkPermission, pool);
  
  console.log('✅ 中间件初始化完成');
}

// 初始化应用（不阻塞服务启动）
initializeApp().catch(console.error);

// 导入错误处理中间件
const { errorHandler, notFoundHandler, requestLogger, performanceMonitor } = require('./middleware/errorHandler');

// 中间件
app.use(requestLogger); // 请求日志
app.use(performanceMonitor); // 性能监控
app.use(helmet()); // 安全头部
app.use(cors({
  origin: process.env.CORS_ORIGIN || '*',
  credentials: true
})); // 跨域支持
app.use(express.json({ limit: '10mb' })); // JSON解析
app.use(express.urlencoded({ extended: true, limit: '10mb' })); // URL编码解析

// 速率限制
const limiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15分钟
  max: 100, // 限制每个IP 15分钟内最多100个请求
  message: '请求过于频繁，请稍后再试'
});
app.use(limiter);

// 基础路由
app.get('/', (req, res) => {
    res.json({
        message: '欢迎使用锡林郭勒盟地区智慧养殖产业平台API服务',
        version: '1.0.0',
        timestamp: new Date().toISOString()
    });
});

app.get('/health', async (req, res) => {
  try {
    // 测试数据库连接
    const connection = await pool.getConnection();
    const [rows] = await connection.execute('SELECT 1 as test');
    connection.release();
    
    res.json({ 
      status: 'OK',
      timestamp: new Date().toISOString(),
      database: 'Connected',
      environment: process.env.NODE_ENV,
      version: '1.0.0'
    });
  } catch (error) {
    res.status(500).json({
      status: 'ERROR',
      timestamp: new Date().toISOString(),
      database: 'Disconnected',
      error: error.message
    });
  }
});

// API路由
app.use('/api/v1/auth', authModule.router);
app.use('/api/v1/users', usersModule.router);
app.use('/api/v1/cattle', cattleModule.router);
app.use('/api/v1/finance', financeModule.router);
app.use('/api/v1/trading', tradingModule.router);
app.use('/api/v1/government', governmentModule.router);
app.use('/api/v1/mall', mallModule.router);

// 数据库查询接口
app.get('/api/v1/database/tables', async (req, res) => {
  try {
    const [tables] = await pool.execute(
      'SELECT TABLE_NAME, TABLE_COMMENT FROM information_schema.TABLES WHERE TABLE_SCHEMA = ?',
      [process.env.DB_NAME]
    );
    
    res.json({
      success: true,
      data: {
        database: process.env.DB_NAME,
        tables: tables,
        count: tables.length
      },
      timestamp: new Date().toISOString()
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error.message,
      timestamp: new Date().toISOString()
    });
  }
});

// 数据库连接状态接口
app.get('/api/v1/database/status', async (req, res) => {
  try {
    const [statusResult] = await pool.execute('SHOW STATUS LIKE "Threads_connected"');
    const [versionResult] = await pool.execute('SELECT VERSION() as version');
    
    res.json({
      success: true,
      data: {
        connected: true,
        version: versionResult[0].version,
        threads_connected: statusResult[0].Value,
        database: process.env.DB_NAME,
        host: process.env.DB_HOST,
        port: process.env.DB_PORT
      },
      timestamp: new Date().toISOString()
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error.message,
      timestamp: new Date().toISOString()
    });
  }
});
app.get('/api/v1/dashboard/map/regions', (req, res) => {
  // 模拟锡林郭勒盟各区域数据
  const regions = [
    {
      id: 'xlg',
      name: '锡林浩特市',
      coordinates: [116.093, 43.946],
      cattle_count: 25600,
      farm_count: 120,
      output_value: 650000000
    },
    {
      id: 'dwq',
      name: '东乌旗',
      coordinates: [116.980, 45.514],
      cattle_count: 18500,
      farm_count: 95,
      output_value: 480000000
    },
    {
      id: 'xwq',
      name: '西乌旗',
      coordinates: [117.615, 44.587],
      cattle_count: 21200,
      farm_count: 108,
      output_value: 520000000
    },
    {
      id: 'abg',
      name: '阿巴嘎旗',
      coordinates: [114.971, 44.022],
      cattle_count: 16800,
      farm_count: 86,
      output_value: 420000000
    },
    {
      id: 'snz',
      name: '苏尼特左旗',
      coordinates: [113.653, 43.859],
      cattle_count: 12400,
      farm_count: 65,
      output_value: 310000000
    }
  ];

  res.json({ regions });
});

app.get('/api/v1/dashboard/map/region/:regionId', (req, res) => {
  const { regionId } = req.params;
  
  // 模拟各区域详细数据
  const regionDetails = {
    'xlg': {
      region: {
        id: 'xlg',
        name: '锡林浩特市',
        coordinates: [116.093, 43.946],
        cattle_count: 25600,
        farm_count: 120,
        output_value: 650000000,
        trend: 'up'
      },
      farms: [
        {
          id: 'FARM001',
          name: '锡林浩特市第一牧场',
          coordinates: [116.120, 43.950],
          cattle_count: 2450,
          output_value: 62000000
        },
        {
          id: 'FARM002',
          name: '锡林浩特市第二牧场',
          coordinates: [116.080, 43.930],
          cattle_count: 2100,
          output_value: 53000000
        }
      ]
    },
    'dwq': {
      region: {
        id: 'dwq',
        name: '东乌旗',
        coordinates: [116.980, 45.514],
        cattle_count: 18500,
        farm_count: 95,
        output_value: 480000000,
        trend: 'up'
      },
      farms: [
        {
          id: 'FARM003',
          name: '东乌旗牧场A',
          coordinates: [116.990, 45.520],
          cattle_count: 1950,
          output_value: 49000000
        }
      ]
    }
  };

  const detail = regionDetails[regionId];
  if (detail) {
    res.json(detail);
  } else {
    res.status(404).json({ error: '区域未找到' });
  }
});

// 错误处理中间件（必须放在所有路由之后）
app.use(notFoundHandler); // 404处理
app.use(errorHandler); // 统一错误处理

// 启动服务器
const HOST = process.env.HOST || '0.0.0.0';

app.listen(PORT, HOST, () => {
  console.log(`API服务器正在监听: http://${HOST}:${PORT}`);
  console.log(`服务器绑定到: ${HOST}, 端口: ${PORT}`);
  console.log('尝试使用以下URL访问:');
  console.log(`  http://localhost:${PORT}`);
  console.log(`  http://127.0.0.1:${PORT}`);
});

module.exports = app;