package v2rayapi

import (
	"errors"
	"net"
	"net/http"

	"github.com/sagernet/sing-box/adapter"
	"github.com/sagernet/sing-box/experimental"
	"github.com/sagernet/sing-box/log"
	"github.com/sagernet/sing-box/option"
	"github.com/sagernet/sing/common"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
)

func init() {
	experimental.RegisterV2RayServerConstructor(NewServer)
}

var _ adapter.V2RayServer = (*Server)(nil)

type Server struct {
	logger       log.Logger
	listen       string
	grpcServer   *grpc.Server
	statsService *StatsService
}

func NewServer(logger log.Logger, options option.V2RayAPIOptions) (adapter.V2RayServer, error) {
	grpcServer := grpc.NewServer(grpc.Creds(insecure.NewCredentials()))
	statsService := NewStatsService(common.PtrValueOrDefault(options.Stats))
	if statsService != nil {
		RegisterStatsServiceServer(grpcServer, statsService)
	}
	server := &Server{
		logger:       logger,
		listen:       options.Listen,
		grpcServer:   grpcServer,
		statsService: statsService,
	}
	return server, nil
}

func (s *Server) Name() string {
	return "v2ray server"
}

func (s *Server) Start(stage adapter.StartStage, scope *adapter.Scope) error {
	switch stage {
	case adapter.StartStateInitialize:
		scope.Add(func() error {
			s.grpcServer.Stop()
			return nil
		})
	case adapter.StartStatePostStart:
		listener, err := net.Listen("tcp", s.listen)
		if err != nil {
			return err
		}
		s.logger.Notice("grpc server started at ", listener.Addr())
		go func() {
			err = s.grpcServer.Serve(listener)
			if err != nil && !errors.Is(err, http.ErrServerClosed) {
				s.logger.Error(err)
			}
		}()
	}
	return nil
}

func (s *Server) StatsService() adapter.ConnectionTracker {
	return s.statsService
}