package heimdallgrpc

import (
	"context"
	"fmt"
	"net"
	"time"

	"github.com/ledgerwatch/erigon-lib/gointerfaces"
	"github.com/ledgerwatch/erigon/consensus/bor/heimdall"
	"github.com/ledgerwatch/log/v3"
	proto "github.com/maticnetwork/polyproto/heimdall"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"google.golang.org/protobuf/types/known/emptypb"
	"google.golang.org/protobuf/types/known/timestamppb"
)

type HeimdallGRPCServer struct {
	proto.UnimplementedHeimdallServer
	heimdall heimdall.HeimdallServer
	logger   log.Logger
}

func (h *HeimdallGRPCServer) Span(ctx context.Context, in *proto.SpanRequest) (*proto.SpanResponse, error) {
	result, err := h.heimdall.Span(ctx, in.ID)

	if err != nil {
		h.logger.Error("[bor.heimdall] Error while fetching span")
		return nil, err
	}

	validators := make([]*proto.Validator, len(result.ValidatorSet.Validators))

	for i, validator := range result.ValidatorSet.Validators {
		h160 := gointerfaces.ConvertAddressToH160(validator.Address)
		validators[i] = &proto.Validator{
			ID: validator.ID,
			Address: &proto.H160{
				Hi: &proto.H128{
					Hi: h160.Hi.Hi,
					Lo: h160.Hi.Lo,
				},
				Lo: h160.Lo,
			},
			VotingPower:      validator.VotingPower,
			ProposerPriority: validator.ProposerPriority,
		}
	}

	var proposer *proto.Validator

	if vsp := result.ValidatorSet.Proposer; vsp != nil {
		proposerH160 := gointerfaces.ConvertAddressToH160(vsp.Address)
		proposer = &proto.Validator{
			ID: vsp.ID,
			Address: &proto.H160{
				Hi: &proto.H128{
					Hi: proposerH160.Hi.Hi,
					Lo: proposerH160.Hi.Lo,
				},
				Lo: proposerH160.Lo,
			},
			VotingPower:      vsp.VotingPower,
			ProposerPriority: vsp.ProposerPriority,
		}
	}

	producers := make([]*proto.Validator, len(result.SelectedProducers))

	for i, producer := range result.SelectedProducers {
		h160 := gointerfaces.ConvertAddressToH160(producer.Address)
		producers[i] = &proto.Validator{
			ID: producer.ID,
			Address: &proto.H160{
				Hi: &proto.H128{
					Hi: h160.Hi.Hi,
					Lo: h160.Hi.Lo,
				},
				Lo: h160.Lo,
			},
			VotingPower:      producer.VotingPower,
			ProposerPriority: producer.ProposerPriority,
		}
	}

	resp := &proto.SpanResponse{
		Result: &proto.Span{
			ID:         result.ID,
			StartBlock: result.StartBlock,
			EndBlock:   result.EndBlock,
			ValidatorSet: &proto.ValidatorSet{
				Validators: validators,
				Proposer:   proposer,
			},
			SelectedProducers: producers,
			ChainID:           result.ChainID,
		},
	}

	return resp, nil
}

func (h *HeimdallGRPCServer) FetchCheckpointCount(ctx context.Context, in *emptypb.Empty) (*proto.FetchCheckpointCountResponse, error) {
	count, err := h.heimdall.FetchCheckpointCount(ctx)

	if err != nil {
		h.logger.Error("[bor.heimdall] Error while fetching checkpoint count")
		return nil, err
	}

	resp := &proto.FetchCheckpointCountResponse{}
	resp.Height = fmt.Sprint(count)

	return resp, nil
}

func (h *HeimdallGRPCServer) FetchCheckpoint(ctx context.Context, in *proto.FetchCheckpointRequest) (*proto.FetchCheckpointResponse, error) {

	_ /*checkpoint*/, err := h.heimdall.FetchCheckpoint(ctx, in.ID)

	if err != nil {
		h.logger.Error("[bor.heimdall] Error while fetching checkpoint")
		return nil, err
	}

	/* TODO

	var hash [32]byte

	copy(hash[:], checkPoint.RootHash.Bytes())

	var address [20]byte

	copy(address[:], checkPoint.Proposer.Bytes())
	*/

	resp := &proto.FetchCheckpointResponse{}

	/* TODO
	resp.Height = fmt.Sprint(result.Height)
	resp.Result = &proto.Checkpoint{
		StartBlock: checkPoint.StartBlock,
		EndBlock:   checkPoint.EndBlock,
		RootHash:   protoutils.ConvertHashToH256(hash),
		Proposer:   protoutils.ConvertAddressToH160(address),
		Timestamp:  timestamppb.New(time.Unix(int64(checkPoint.TimeStamp), 0)),
		BorChainID: checkPoint.BorChainID,
	}
	*/
	return resp, nil
}

func (h *HeimdallGRPCServer) StateSyncEvents(req *proto.StateSyncEventsRequest, reply proto.Heimdall_StateSyncEventsServer) error {
	fromId := req.FromID

	for {
		height, events, err := h.heimdall.StateSyncEvents(context.Background(), fromId, int64(req.ToTime), int(req.Limit))

		if err != nil {
			h.logger.Error("[bor.heimdall] Error while fetching event records", "error", err)
			return status.Errorf(codes.Internal, err.Error())
		}

		eventRecords := make([]*proto.EventRecord, len(events))

		for i, event := range events {
			eventRecords[i] = &proto.EventRecord{
				ID:       event.ID,
				Contract: event.Contract.Hex(),
				Data:     event.Data.String(),
				TxHash:   event.TxHash.Hex(),
				LogIndex: event.LogIndex,
				ChainID:  event.ChainID,
				Time:     timestamppb.New(event.Time),
			}
		}

		if len(eventRecords) == 0 {
			break
		}

		err = reply.Send(&proto.StateSyncEventsResponse{
			Height: fmt.Sprint(height),
			Result: eventRecords,
		})

		if err != nil {
			h.logger.Error("[bor.heimdall] Error while sending event record", "error", err)
			return status.Errorf(codes.Internal, err.Error())
		}

		if len(eventRecords) < int(req.Limit) {
			break
		}

		fromId += req.Limit
	}

	return nil
}

// StartHeimdallServer creates a heimdall GRPC server - which is implemented via the passed in client
// interface.  It is intended for use in testing where more than a single test validator is required rather
// than to replace the maticnetwork implementation
func StartHeimdallServer(shutDownCtx context.Context, heimdall heimdall.HeimdallServer, addr string, logger log.Logger) error {
	grpcServer := grpc.NewServer(withLoggingUnaryInterceptor(logger))
	proto.RegisterHeimdallServer(grpcServer,
		&HeimdallGRPCServer{
			heimdall: heimdall,
			logger:   logger,
		})

	lis, err := net.Listen("tcp", addr)
	if err != nil {
		return err
	}

	go func() {
		if err := grpcServer.Serve(lis); err != nil {
			logger.Error("[bor.heimdall] failed to serve grpc server", "err", err)
		}

		<-shutDownCtx.Done()
		grpcServer.Stop()
		lis.Close()
		logger.Info("[bor.heimdall] GRPC Server stopped", "addr", addr)
	}()

	logger.Info("[bor.heimdall] GRPC Server started", "addr", addr)

	return nil
}

func withLoggingUnaryInterceptor(logger log.Logger) grpc.ServerOption {
	return grpc.UnaryInterceptor(func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
		start := time.Now()

		h, err := handler(ctx, req)
		if err != nil {
			err = status.Errorf(codes.Internal, err.Error())
		}

		logger.Debug("[bor.heimdall] Request", "method", info.FullMethod, "duration", time.Since(start), "error", err)

		return h, err
	})
}