package plugin

import (
	"context"
	"errors"
	"fmt"
	"net"

	"github.com/Neur0toxine/sshpoke/internal/server"
	"github.com/Neur0toxine/sshpoke/internal/server/driver/plugin"
	"github.com/Neur0toxine/sshpoke/pkg/convert"
	"github.com/Neur0toxine/sshpoke/pkg/plugin/pb"
	"go.uber.org/zap"
	"google.golang.org/grpc"
	"google.golang.org/grpc/metadata"
	"google.golang.org/protobuf/types/known/emptypb"
)

var ErrUnauthorized = errors.New("unauthorized")

type pluginAPI struct {
	pb.UnimplementedPluginServiceServer
	log *zap.SugaredLogger
}

func (p *pluginAPI) Event(_ *emptypb.Empty, stream pb.PluginService_EventServer) error {
	pl := p.receiverForContext(stream.Context())
	if pl == nil {
		return ErrUnauthorized
	}
	p.log.Debugw("attached plugin event stream", "serverName", pl.Name())
	err := pl.Listen(stream.Context(), &Stream{stream: stream})
	if err != nil {
		p.log.Debugw("detached plugin event stream", "serverName", pl.Name(), "error", err)
		return err
	}
	p.log.Debugw("detached plugin event stream", "serverName", pl.Name())
	return nil
}

func (p *pluginAPI) EventStatus(ctx context.Context, msg *pb.EventStatusMessage) (*emptypb.Empty, error) {
	pl := p.receiverForContext(ctx)
	if pl == nil {
		return nil, ErrUnauthorized
	}
	pl.PushEventStatus(convert.MessageToAppEventStatus(msg))
	return &emptypb.Empty{}, nil
}

func (p *pluginAPI) receiverForContext(ctx context.Context) plugin.Plugin {
	md, ok := metadata.FromIncomingContext(ctx)
	if !ok {
		return nil
	}
	tokens := md.Get("token")
	if len(tokens) != 1 {
		return nil
	}
	return server.DefaultManager.PluginByToken(tokens[0])
}

func StartServer(ctx context.Context, port int, log *zap.SugaredLogger) {
	socket, err := net.Listen("tcp", fmt.Sprintf(":%d", port))
	if err != nil {
		log.Errorf("cannot start plugin API server on port %d: %s", port, err)
		return
	}
	s := grpc.NewServer()
	pb.RegisterPluginServiceServer(s, &pluginAPI{log: log})
	log.Debugf("starting plugin server on :%d", port)
	go func() {
		<-ctx.Done()
		s.GracefulStop()
		socket.Close()
	}()
	if err := s.Serve(socket); err != nil {
		log.Fatalf("cannot start plugin server on :%d: %s", port, err)
	}
}