import express from 'express';
import cors from 'cors';
import helmet from 'helmet';
import morgan from 'morgan';
import compression from 'compression';
import { createServer } from 'http';
import { createConnection, createServer as createNetServer } from 'net';
import { exec } from 'child_process';
import { promisify } from 'util';
import { config } from './config/index.js';
import { errorHandler } from './middleware/error.js';
import { setupRoutes } from './routes/index.js';
import { setupWebSocket } from './websocket/index.js';
import { initDatabase } from './models/index.js';
import { initRedis } from './config/redis.js';
import { logger } from './utils/logger.js';
import { taskScheduler } from './scheduler/index.js';
import { registerTaskExecutors } from './services/taskExecutors.js';
import { taskQueueService } from './services/TaskQueueService.js';
import { browserLoginService } from './services/BrowserLoginService.js';
import { wsManager } from './websocket/index.js';

const execAsync = promisify(exec);

const app = express();
const httpServer = createServer(app);

// 中间件
app.use(helmet({
  crossOriginResourcePolicy: { policy: 'cross-origin' },
}));
app.use(cors({
  origin: config.cors.origin,
  credentials: true,
}));
app.use(compression());
app.use(morgan('combined', {
  stream: { write: (message) => logger.info(message.trim()) },
}));
app.use(express.json({ limit: '50mb' }));
app.use(express.urlencoded({ extended: true, limit: '50mb' }));

// 静态文件
app.use('/uploads', express.static(config.upload.path));

// 健康检查
app.get('/api/health', (_req, res) => {
  res.json({
    status: 'ok',
    version: config.version,
    uptime: process.uptime(),
    timestamp: new Date().toISOString(),
  });
});

// API 路由
setupRoutes(app);

// 错误处理
app.use(errorHandler);

// WebSocket
setupWebSocket(httpServer);

// 检查端口是否被占用（改进版：使用 net.Server 来测试）
async function checkPortInUse(port: number): Promise<boolean> {
  return new Promise((resolve) => {
    const testServer = createNetServer();
    
    testServer.once('error', (err: NodeJS.ErrnoException) => {
      if (err.code === 'EADDRINUSE') {
        resolve(true); // 端口被占用
      } else {
        resolve(false);
      }
    });
    
    testServer.once('listening', () => {
      testServer.close(() => {
        resolve(false); // 端口未被占用
      });
    });
    
    testServer.listen(port);
  });
}

// 获取占用端口的进程ID（跨平台）
async function getProcessOnPort(port: number): Promise<number | null> {
  const isWindows = process.platform === 'win32';
  
  try {
    if (isWindows) {
      // Windows: 使用 netstat 命令，改进解析逻辑
      const { stdout } = await execAsync(`netstat -ano | findstr :${port}`);
      const lines = stdout.trim().split('\n');
      for (const line of lines) {
        // 匹配 LISTENING 状态的连接
        if (line.includes('LISTENING')) {
          const parts = line.trim().split(/\s+/);
          const pid = parseInt(parts[parts.length - 1], 10);
          if (!isNaN(pid) && pid > 0) {
            logger.info(`[Port Check] Found PID ${pid} listening on port ${port}`);
            return pid;
          }
        }
      }
    } else {
      const { stdout } = await execAsync(`lsof -i :${port} -t`);
      const pid = parseInt(stdout.trim().split('\n')[0], 10);
      if (!isNaN(pid)) return pid;
    }
  } catch (error) {
    // 命令执行失败，可能端口没有被占用
    logger.debug(`[Port Check] Command failed (port might not be in use):`, error);
  }
  return null;
}

// 终止进程（跨平台）
async function killProcess(pid: number): Promise<boolean> {
  const isWindows = process.platform === 'win32';
  const currentPid = process.pid;
  
  // 不要杀死自己的进程
  if (pid === currentPid) {
    logger.warn(`[Port Check] Cannot kill own process (PID: ${pid})`);
    return false;
  }
  
  try {
    if (isWindows) {
      await execAsync(`taskkill /PID ${pid} /F`);
    } else {
      await execAsync(`kill -9 ${pid}`);
    }
    // 等待进程完全终止
    await new Promise(resolve => setTimeout(resolve, 2000));
    return true;
  } catch (error) {
    logger.error(`Failed to kill process ${pid}:`, error);
    return false;
  }
}

// 检查并释放端口（增加重试机制）
async function ensurePortAvailable(port: number, maxRetries: number = 3): Promise<void> {
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    const inUse = await checkPortInUse(port);
    
    if (!inUse) {
      logger.info(`[Port Check] Port ${port} is available`);
      return;
    }
    
    logger.warn(`[Port Check] Attempt ${attempt}/${maxRetries}: Port ${port} is already in use`);
    
    const pid = await getProcessOnPort(port);
    
    if (pid) {
      logger.info(`[Port Check] Found process ${pid} using port ${port}, attempting to terminate...`);
      const killed = await killProcess(pid);
      
      if (killed) {
        logger.info(`[Port Check] Successfully terminated process ${pid}`);
        // 等待更长时间让端口释放
        await new Promise(resolve => setTimeout(resolve, 2000));
        
        // 再次检查端口
        const stillInUse = await checkPortInUse(port);
        if (!stillInUse) {
          logger.info(`[Port Check] Port ${port} is now available`);
          return;
        }
      }
    } else {
      logger.warn(`[Port Check] Port ${port} is in use but could not identify the process`);
    }
    
    // 如果还有重试机会，等待一会儿
    if (attempt < maxRetries) {
      logger.info(`[Port Check] Waiting before retry...`);
      await new Promise(resolve => setTimeout(resolve, 3000));
    }
  }
  
  throw new Error(`Port ${port} is still in use after ${maxRetries} attempts. Please manually kill the process or use a different port.`);
}

// 启动服务
async function bootstrap() {
  // 确保端口可用
  try {
    await ensurePortAvailable(config.port);
  } catch (error) {
    logger.error('Port availability check failed:', error);
    process.exit(1);
  }
  
  let dbConnected = false;
  let redisConnected = false;

  // 尝试初始化数据库
  try {
    await initDatabase();
    logger.info('Database connected');
    dbConnected = true;
  } catch (error) {
    logger.warn('Database connection failed - running in limited mode');
    logger.warn('Please install MySQL and create the database, or use Docker');
    logger.error('Database error:', error instanceof Error ? error.message : error);
  }

  // 尝试初始化 Redis
  try {
    await initRedis();
    logger.info('Redis connected');
    redisConnected = true;
  } catch (error) {
    logger.warn('Redis connection failed - some features may not work');
  }

  // 只有在数据库连接成功时才启动调度器和注册任务执行器
  if (dbConnected) {
    registerTaskExecutors();
    taskScheduler.start();
    
    // 启动任务队列 Worker
    taskQueueService.startWorker();
  }

  // 注册浏览器登录服务的事件监听（用于 AI 分析结果的 WebSocket 推送）
  setupBrowserLoginEvents();

  // 启动 HTTP 服务
  httpServer.listen(config.port, config.host, () => {
    logger.info(`Server running on http://${config.host}:${config.port}`);
    logger.info(`Environment: ${config.env}`);
    if (!dbConnected) {
      logger.warn('⚠️  Running without database - API endpoints will not work');
      logger.warn('⚠️  Please configure MySQL in .env file');
    }
  });
}

/**
 * 设置浏览器登录服务的事件监听
 * 用于通过 WebSocket 推送 AI 分析结果给前端
 */
function setupBrowserLoginEvents(): void {
  // AI 分析结果事件
  browserLoginService.on('aiAnalysis', (data: {
    sessionId: string;
    userId?: number;
    status: string;
    analysis: {
      isLoggedIn: boolean;
      hasVerification: boolean;
      verificationType?: string;
      verificationDescription?: string;
      pageDescription: string;
      suggestedAction?: string;
    };
  }) => {
    if (data.userId) {
      wsManager.sendToUser(data.userId, 'login:aiAnalysis', {
        sessionId: data.sessionId,
        status: data.status,
        analysis: data.analysis,
      });
    }
  });

  // 验证码检测事件
  browserLoginService.on('verificationNeeded', (data: {
    sessionId: string;
    userId?: number;
    verificationType?: string;
    description?: string;
    suggestedAction?: string;
  }) => {
    if (data.userId) {
      wsManager.sendToUser(data.userId, 'login:verificationNeeded', {
        sessionId: data.sessionId,
        verificationType: data.verificationType,
        description: data.description,
        suggestedAction: data.suggestedAction,
      });
    }
  });

  // 导航建议事件
  browserLoginService.on('navigationSuggestion', (data: {
    sessionId: string;
    userId?: number;
    guide: unknown;
  }) => {
    if (data.userId) {
      wsManager.sendToUser(data.userId, 'login:navigationSuggestion', {
        sessionId: data.sessionId,
        guide: data.guide,
      });
    }
  });

  // 登录结果事件（也通过 WebSocket 推送）
  browserLoginService.on('loginResult', (data: {
    sessionId: string;
    userId?: number;
    status: string;
    cookies?: string;
    accountInfo?: unknown;
    error?: string;
    message?: string;
  }) => {
    logger.info(`[BrowserLogin] Login result event: ${data.sessionId}, status: ${data.status}`);
    if (data.userId) {
      wsManager.sendToUser(data.userId, 'login:result', {
        sessionId: data.sessionId,
        status: data.status,
        accountInfo: data.accountInfo,
        error: data.error,
        message: data.message,
      });
    }
  });

  logger.info('Browser login events registered');
}

// 优雅关闭
process.on('SIGTERM', async () => {
  logger.info('SIGTERM received, shutting down gracefully');
  taskScheduler.stop();
  await taskQueueService.close();
  httpServer.close(() => {
    logger.info('Server closed');
    process.exit(0);
  });
});

bootstrap();

export { app, httpServer };