/*
	This file contains the grpc cli server-side calls.
    Functions here should call other functions in charge of the
	particular task.
*/

package nucleus

import (
	"context"
	"io"
	"net"
	"os"
	"sync"

	pb "code.fbi.h-da.de/cocsn/gosdn/api/proto"
	"code.fbi.h-da.de/cocsn/gosdn/log"
	"code.fbi.h-da.de/cocsn/gosdn/sbi/restconf/client/ciena"
	"google.golang.org/grpc"
	"google.golang.org/grpc/health"
	healthpb "google.golang.org/grpc/health/grpc_health_v1"
	"google.golang.org/protobuf/types/known/emptypb"
)

type logConnection struct {
	stream pb.GrpcCli_CreateLogStreamServer
	id     string
	active bool
	error  chan error
}

// server is used to implement the grcp cli server
type server struct {
	pb.UnimplementedGrpcCliServer
	core           *Core
	logConnections []*logConnection
}

var srv *server

type buf []byte

func (b *buf) Write(p []byte) (n int, err error) {

	reply := pb.LogReply{Log: string(p)}
	srv.BroadcastLog(&reply)
	return len(p), nil
}

func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
	log.Info("Received: ", in.GetName())
	return &pb.HelloReply{Message: "Hello " + in.GetName(), GoSDNInfo: "goSDN in version: DEVELOP"}, nil
}

//GetLog creates a continuous stream between client and server to send goSDN logs
func (s *server) CreateLogStream(req *emptypb.Empty, stream pb.GrpcCli_CreateLogStreamServer) error {
	conn := &logConnection{
		stream: stream,
		active: true,
		error:  make(chan error),
	}
	s.logConnections = append(s.logConnections, conn)

	return <-conn.error
}

func (s *server) BroadcastLog(log *pb.LogReply) {
	wait := sync.WaitGroup{}
	done := make(chan int)

	for _, conn := range s.logConnections {
		wait.Add(1)

		go func(conn *logConnection) {
			defer wait.Done()
			if conn.active {
				err := conn.stream.Send(log)

				if err != nil {
					conn.active = false
					conn.error <- err
				}
			}
		}(conn)
	}

	go func() {
		//blocks until all send routines are finished
		wait.Wait()
		close(done)
	}()

	<-done
}

func (s *server) Shutdown(ctx context.Context, in *pb.ShutdownRequest) (*pb.ShutdownReply, error) {
	log.Info("Shutdown Received: ", in.GetName())
	s.core.IsRunning <- false
	return &pb.ShutdownReply{Message: "Shutdown " + in.GetName()}, nil
}

func getCLIGoing(core *Core) {

	var (
		logConnections []*logConnection
		logBuffer      buf
		system         = ""
	)

	log.Info("Starting: GetCLIGoing")
	// Boot-up the control interface for the cli
	cliControlListener, err := net.Listen("tcp", core.config.CliSocket)
	if err != nil {
		log.Fatal(err)
	}

	cliControlServer := grpc.NewServer()
	healthCheck := health.NewServer()
	srv = &server{core: core, logConnections: logConnections}

	//TODO: move?
	wrt := io.MultiWriter(os.Stdout, &logBuffer)
	log.Output(wrt)

	healthpb.RegisterHealthServer(cliControlServer, healthCheck)
	pb.RegisterGrpcCliServer(cliControlServer, srv)

	healthCheck.SetServingStatus(system, healthpb.HealthCheckResponse_SERVING)

	if err := cliControlServer.Serve(cliControlListener); err != nil {
		log.Fatal(err)
	}
}

// SBI specific calls, by now TAPI only
func (s *server) TAPIGetEdge(ctx context.Context, in *pb.TAPIRequest) (*pb.TAPIReply, error) {
	log.Info("Received: ", in.GetName())
	if err := s.core.clients["ciena-mcp"].(*ciena.MCPClient).GetNodes(); err != nil {
		log.Error(err)
		return &pb.TAPIReply{Message: "TAPI error"}, nil
	}
	return &pb.TAPIReply{Message: "Done"}, nil
}

func (s *server) TAPIGetEdgeNode(ctx context.Context, in *pb.TAPIRequest) (*pb.TAPIReply, error) {
	log.Info("Received: ", in.GetName())
	if err := s.core.clients["ciena-mcp"].(*ciena.MCPClient).GetNodeEdgePoints(); err != nil {
		log.Error(err)
		return &pb.TAPIReply{Message: "TAPI error"}, nil
	}
	return &pb.TAPIReply{Message: "Done"}, nil
}

func (s *server) TAPIGetLink(ctx context.Context, in *pb.TAPIRequest) (*pb.TAPIReply, error) {
	log.Info("Received: ", in.GetName())
	if err := s.core.clients["ciena-mcp"].(*ciena.MCPClient).GetLinks(); err != nil {
		log.Error(err)
		return &pb.TAPIReply{Message: "TAPI error"}, nil
	}
	return &pb.TAPIReply{Message: "Done"}, nil
}