package server

import (
	"fmt"
	"log"
	"net"
	"time"

	pb "net-tunnel/pkg/proto"

	"google.golang.org/grpc"
)

// Server 表示服务端
type Server struct {
	pb.UnimplementedTunnelServiceServer
	clientManager *ClientManager
	proxyManager  *ProxyManager
	grpcServer    *grpc.Server
	bindAddr      string
	bindPort      int
}

// NewServer 创建一个新的服务端
func NewServer(bindAddr string, bindPort int) *Server {
	clientManager := NewClientManager()
	return &Server{
		clientManager: clientManager,
		proxyManager:  NewProxyManager(clientManager),
		bindAddr:      bindAddr,
		bindPort:      bindPort,
	}
}

// Start 启动服务端
func (s *Server) Start() error {
	addr := fmt.Sprintf("%s:%d", s.bindAddr, s.bindPort)
	lis, err := net.Listen("tcp", addr)
	if err != nil {
		return fmt.Errorf("failed to listen: %v", err)
	}

	s.grpcServer = grpc.NewServer()
	pb.RegisterTunnelServiceServer(s.grpcServer, s)

	log.Printf("Server started, listening on %s", addr)
	return s.grpcServer.Serve(lis)
}

// Stop 停止服务端
func (s *Server) Stop() {
	if s.grpcServer != nil {
		s.grpcServer.GracefulStop()
	}
}

// Connect 实现 gRPC 服务方法
func (s *Server) Connect(stream pb.TunnelService_ConnectServer) error {
	// 创建控制连接
	clientID := "client_" + fmt.Sprint(time.Now().UnixNano())
	conn := NewClientConnection(stream)

	// 添加客户端
	s.clientManager.Add(clientID, conn)
	defer s.clientManager.Remove(clientID)

	log.Printf("New control connection established: %s", clientID)

	// 接收客户端消息
	for {
		msg, err := stream.Recv()
		if err != nil {
			log.Printf("Control connection closed: %v", err)
			// 清理该客户端的代理
			s.proxyManager.UnregisterAllProxies(clientID)
			return err
		}

		// 处理不同类型的消息
		switch content := msg.GetContent().(type) {
		case *pb.Message_RegisterConfigs:
			// 处理代理配置注册
			s.handleProxyRegister(clientID, content)
		case *pb.Message_ProxyData:
			s.handleProxyData(clientID, content)
		default:
			log.Printf("收到未知类型的消息")
		}
	}
}

func (s *Server) handleProxyRegister(clientID string, msg *pb.Message_RegisterConfigs) {
	hasError := false

	conn, ok := s.clientManager.Get(clientID)
	if !ok {
		log.Printf("Control connection not found for client %s", clientID)
		return
	}

	for _, config := range msg.RegisterConfigs.GetConfigs() {
		if err := s.proxyManager.RegisterProxy(clientID, config); err != nil {
			log.Printf("Failed to register proxy %s: %v", config.Name, err)
			msg := &pb.Message_RegisterProxiesError{
				RegisterProxiesError: &pb.RegisterProxiesError{
					ProxyConfig: config,
					Error:       err.Error(),
				},
			}

			if err := conn.Send(&pb.Message{
				Content: msg,
			}); err != nil {
				log.Printf("Failed to send message to client %s: %v", clientID, err)
			}
			hasError = true
			break
		}
	}
	if !hasError {
		if err := conn.Send(&pb.Message{
			Content: msg,
		}); err != nil {
			log.Printf("Failed to send message to client %s: %v", clientID, err)
		}
	}
}

func (s *Server) handleProxyData(clientID string, msg *pb.Message_ProxyData) {
	switch msg.ProxyData.ProxyConfig.Type {
	case pb.ProxyType_TCP:
		s.handleTCPProxyData(clientID, msg)
	case pb.ProxyType_UDP:
		s.handleUDPProxyData(clientID, msg)
	}
}

func (s *Server) handleUDPProxyData(clientID string, msg *pb.Message_ProxyData) {
	proxyEntry, ok := s.proxyManager.proxies.Load(msg.ProxyData.ProxyConfig.Name)
	if !ok {
		log.Printf("Proxy %s not found", msg.ProxyData.ProxyConfig.Name)
		return
	}
	entry := proxyEntry.(*ProxyEntry)
	addr, ok := entry.UDPAddrs.Load(msg.ProxyData.ConnId)
	if !ok {
		log.Printf("UDP connection %s not found", msg.ProxyData.ConnId)
		return
	}
	_, err := entry.UDPConn.WriteToUDP(msg.ProxyData.Data, addr.(*net.UDPAddr))
	if err != nil {
		log.Printf("Failed to write data to UDP connection: %v", err)
		entry.UDPAddrs.Delete(msg.ProxyData.ConnId)
		controlConn, ok := s.clientManager.Get(clientID)
		if !ok {
			log.Printf("Control connection not found for client %s", clientID)
			return
		}
		if err := controlConn.Send(&pb.Message{
			Content: &pb.Message_ProxyError{
				ProxyError: &pb.ProxyError{
					ProxyConfig: msg.ProxyData.ProxyConfig,
					ConnId:      msg.ProxyData.ConnId,
					Error:       "Failed to write data to UDP connection",
				},
			},
		}); err != nil {
			log.Printf("Failed to send message to client %s: %v", clientID, err)
			return
		}
	}
}

func (s *Server) handleTCPProxyData(clientID string, msg *pb.Message_ProxyData) {
	proxyEntry, ok := s.proxyManager.proxies.Load(msg.ProxyData.ProxyConfig.Name)
	if !ok {
		log.Printf("Proxy %s not found", msg.ProxyData.ProxyConfig.Name)
		return
	}
	entry := proxyEntry.(*ProxyEntry)
	conn, ok := entry.TCPConns.Load(msg.ProxyData.ConnId)
	if !ok {
		log.Printf("TCP connection %s not found", msg.ProxyData.ConnId)
		controlConn, ok := s.clientManager.Get(clientID)
		if ok {
			if err := controlConn.Send(&pb.Message{
				Content: &pb.Message_ProxyError{
					ProxyError: &pb.ProxyError{
						ProxyConfig: msg.ProxyData.ProxyConfig,
						ConnId:      msg.ProxyData.ConnId,
						Error:       "TCP connection not found",
					},
				},
			}); err != nil {
				log.Printf("Failed to send message to client %s: %v", clientID, err)
			}
		}
		return
	}
	_, err := conn.(net.Conn).Write(msg.ProxyData.Data)
	if err != nil {
		log.Printf("Failed to write data to TCP connection: %v", err)
		conn.(net.Conn).Close()
		entry.TCPConns.Delete(msg.ProxyData.ConnId)
		controlConn, ok := s.clientManager.Get(clientID)
		if ok {
			if err := controlConn.Send(&pb.Message{
				Content: &pb.Message_ProxyError{
					ProxyError: &pb.ProxyError{
						ProxyConfig: msg.ProxyData.ProxyConfig,
						ConnId:      msg.ProxyData.ConnId,
						Error:       "Failed to write data to TCP connection",
					},
				},
			}); err != nil {
				log.Printf("Failed to send message to client %s: %v", clientID, err)
			}
		}
	}
}