package data

import (
	"bytes"
	"encoding/binary"
	"time"

	"github.com/iden3/go-iden3-crypto/poseidon"
	pcrypto "github.com/libp2p/go-libp2p/core/crypto"
	"github.com/libp2p/go-libp2p/core/peer"
	"github.com/pkg/errors"
	"go.uber.org/zap"
	"google.golang.org/protobuf/proto"
	"google.golang.org/protobuf/types/known/anypb"
	"source.quilibrium.com/quilibrium/monorepo/node/config"
	"source.quilibrium.com/quilibrium/monorepo/node/protobufs"
)

func (e *DataClockConsensusEngine) runMessageHandler() {
	for {
		select {
		case message := <-e.messageProcessorCh:
			e.logger.Debug("handling message")
			msg := &protobufs.Message{}

			if err := proto.Unmarshal(message.Data, msg); err != nil {
				continue
			}

			e.peerMapMx.RLock()
			peer, ok := e.peerMap[string(message.From)]
			e.peerMapMx.RUnlock()

			if ok && bytes.Compare(peer.version, config.GetMinimumVersion()) >= 0 &&
				bytes.Equal(
					e.frameProverTries[0].FindNearest(e.provingKeyAddress).External.Key,
					e.provingKeyAddress,
				) && e.syncingStatus == SyncStatusNotSyncing {
				for name := range e.executionEngines {
					name := name
					go func() error {
						messages, err := e.executionEngines[name].ProcessMessage(
							msg.Address,
							msg,
						)
						if err != nil {
							e.logger.Debug(
								"could not process message for engine",
								zap.Error(err),
								zap.String("engine_name", name),
							)
							return nil
						}

						for _, appMessage := range messages {
							appMsg := &anypb.Any{}
							err := proto.Unmarshal(appMessage.Payload, appMsg)
							if err != nil {
								e.logger.Error(
									"could not unmarshal app message",
									zap.Error(err),
									zap.String("engine_name", name),
								)
								continue
							}

							switch appMsg.TypeUrl {
							case protobufs.TokenRequestType:
								t := &protobufs.TokenRequest{}
								err := proto.Unmarshal(appMsg.Value, t)
								if err != nil {
									continue
								}

								if err := e.handleTokenRequest(t); err != nil {
									continue
								}
							}
						}

						return nil
					}()
				}
			}

			any := &anypb.Any{}
			if err := proto.Unmarshal(msg.Payload, any); err != nil {
				e.logger.Error("error while unmarshaling", zap.Error(err))
				continue
			}

			go func() {
				switch any.TypeUrl {
				case protobufs.ClockFrameType:
					if !ok || bytes.Compare(
						peer.version,
						config.GetMinimumVersion(),
					) < 0 {
						e.logger.Debug("received frame from unknown or outdated peer")
						return
					}
					if err := e.handleClockFrameData(
						message.From,
						msg.Address,
						any,
						false,
					); err != nil {
						return
					}
				case protobufs.DataPeerListAnnounceType:
					if err := e.handleDataPeerListAnnounce(
						message.From,
						msg.Address,
						any,
					); err != nil {
						return
					}
				}
			}()
		}
	}
}

func (e *DataClockConsensusEngine) handleDataPeerListAnnounce(
	peerID []byte,
	address []byte,
	any *anypb.Any,
) error {
	announce := &protobufs.DataPeerListAnnounce{}
	if err := any.UnmarshalTo(announce); err != nil {
		return errors.Wrap(err, "handle data peer list announce")
	}

	for _, p := range announce.PeerList {
		if bytes.Equal(p.PeerId, e.pubSub.GetPeerID()) {
			continue
		}

		if !bytes.Equal(p.PeerId, peerID) {
			continue
		}

		if p.PublicKey == nil || p.Signature == nil || p.Version == nil {
			continue
		}

		if p.PublicKey != nil && p.Signature != nil && p.Version != nil {
			key, err := pcrypto.UnmarshalEd448PublicKey(p.PublicKey)
			if err != nil {
				e.logger.Warn(
					"peer announcement contained invalid pubkey",
					zap.Binary("public_key", p.PublicKey),
				)
				continue
			}

			if !(peer.ID(p.PeerId)).MatchesPublicKey(key) {
				e.logger.Warn(
					"peer announcement peer id does not match pubkey",
					zap.Binary("peer_id", p.PeerId),
					zap.Binary("public_key", p.PublicKey),
				)
				continue
			}

			msg := binary.BigEndian.AppendUint64([]byte{}, p.MaxFrame)
			msg = append(msg, p.Version...)
			msg = binary.BigEndian.AppendUint64(msg, uint64(p.Timestamp))
			b, err := key.Verify(msg, p.Signature)
			if err != nil || !b {
				e.logger.Warn(
					"peer provided invalid signature",
					zap.Binary("msg", msg),
					zap.Binary("public_key", p.PublicKey),
					zap.Binary("signature", p.Signature),
				)
				continue
			}

			if bytes.Compare(p.Version, config.GetMinimumVersion()) < 0 &&
				p.Timestamp > config.GetMinimumVersionCutoff().UnixMilli() {
				e.logger.Debug(
					"peer provided outdated version, penalizing app score",
					zap.Binary("peer_id", p.PeerId),
				)
				e.pubSub.SetPeerScore(p.PeerId, -10000)
				continue
			}
		}

		e.peerMapMx.RLock()
		if _, ok := e.uncooperativePeersMap[string(p.PeerId)]; ok {
			e.peerMapMx.RUnlock()
			continue
		}
		e.peerMapMx.RUnlock()

		multiaddr := e.pubSub.GetMultiaddrOfPeer(p.PeerId)

		e.pubSub.SetPeerScore(p.PeerId, 10)

		e.peerMapMx.RLock()
		existing, ok := e.peerMap[string(p.PeerId)]
		e.peerMapMx.RUnlock()

		if ok {
			if existing.signature != nil && p.Signature == nil {
				continue
			}

			if existing.publicKey != nil && p.PublicKey == nil {
				continue
			}

			if existing.version != nil && p.Version == nil {
				continue
			}

			if existing.timestamp > p.Timestamp {
				continue
			}
		}

		e.peerMapMx.Lock()
		e.peerMap[string(p.PeerId)] = &peerInfo{
			peerId:        p.PeerId,
			multiaddr:     multiaddr,
			maxFrame:      p.MaxFrame,
			direct:        bytes.Equal(p.PeerId, peerID),
			lastSeen:      time.Now().Unix(),
			timestamp:     p.Timestamp,
			version:       p.Version,
			signature:     p.Signature,
			publicKey:     p.PublicKey,
			totalDistance: p.TotalDistance,
		}
		e.peerMapMx.Unlock()
	}

	return nil
}

func (e *DataClockConsensusEngine) handleTokenRequest(
	transition *protobufs.TokenRequest,
) error {
	e.stagedTransactionsMx.Lock()
	if e.stagedTransactions == nil {
		e.stagedTransactions = &protobufs.TokenRequests{}
	}

	found := false
	for _, ti := range e.stagedTransactions.Requests {
		switch t := ti.Request.(type) {
		case *protobufs.TokenRequest_Transfer:
			switch r := transition.Request.(type) {
			case *protobufs.TokenRequest_Transfer:
				if bytes.Equal(r.Transfer.OfCoin.Address, t.Transfer.OfCoin.Address) {
					found = true
				}
			}
		case *protobufs.TokenRequest_Split:
			switch r := transition.Request.(type) {
			case *protobufs.TokenRequest_Split:
				if bytes.Equal(r.Split.OfCoin.Address, r.Split.OfCoin.Address) {
					found = true
				}
			}
		case *protobufs.TokenRequest_Merge:
			switch r := transition.Request.(type) {
			case *protobufs.TokenRequest_Merge:
			checkmerge:
				for i := range t.Merge.Coins {
					for j := range r.Merge.Coins {
						if bytes.Equal(t.Merge.Coins[i].Address, r.Merge.Coins[j].Address) {
							found = true
							break checkmerge
						}
					}
				}
			}
		case *protobufs.TokenRequest_Mint:
			switch r := transition.Request.(type) {
			case *protobufs.TokenRequest_Mint:
			checkmint:
				for i := range t.Mint.Proofs {
					for j := range r.Mint.Proofs {
						if bytes.Equal(t.Mint.Proofs[i], r.Mint.Proofs[j]) {
							found = true
							break checkmint
						}
					}
				}
			}
		}
	}

	if !found {
		e.stagedTransactions.Requests = append(
			e.stagedTransactions.Requests,
			transition,
		)
	}
	e.stagedTransactionsMx.Unlock()
	return nil
}

func (e *DataClockConsensusEngine) handleClockFrameData(
	peerID []byte,
	address []byte,
	any *anypb.Any,
	isSync bool,
) error {
	frame := &protobufs.ClockFrame{}
	if err := any.UnmarshalTo(frame); err != nil {
		return errors.Wrap(err, "handle clock frame data")
	}

	if e.latestFrameReceived > frame.FrameNumber {
		return nil
	}

	addr, err := poseidon.HashBytes(
		frame.GetPublicKeySignatureEd448().PublicKey.KeyValue,
	)
	if err != nil {
		return errors.Wrap(err, "handle clock frame data")
	}

	for _, trie := range e.frameProverTries {
		prover := trie.FindNearest(addr.Bytes())
		if !bytes.Equal(prover.External.Key, addr.Bytes()) {
			e.logger.Info(
				"prover not in trie at frame, address may be in fork",
				zap.Binary("address", address),
				zap.Binary("filter", frame.Filter),
				zap.Uint64("frame_number", frame.FrameNumber),
			)
			return nil
		}
	}

	e.logger.Info(
		"got clock frame",
		zap.Binary("address", address),
		zap.Binary("filter", frame.Filter),
		zap.Uint64("frame_number", frame.FrameNumber),
		zap.Int("proof_count", len(frame.AggregateProofs)),
	)

	if err := e.frameProver.VerifyDataClockFrame(frame); err != nil {
		e.logger.Error("could not verify clock frame", zap.Error(err))
		return errors.Wrap(err, "handle clock frame data")
	}

	if err := e.inclusionProver.VerifyFrame(frame); err != nil {
		e.logger.Error("could not verify clock frame", zap.Error(err))
		return errors.Wrap(err, "handle clock frame data")
	}

	e.logger.Info(
		"clock frame was valid",
		zap.Binary("address", address),
		zap.Binary("filter", frame.Filter),
		zap.Uint64("frame_number", frame.FrameNumber),
	)

	if e.latestFrameReceived < frame.FrameNumber {
		e.latestFrameReceived = frame.FrameNumber
		go func() {
			select {
			case e.frameChan <- frame:
			default:
			}
		}()
	}

	head, err := e.dataTimeReel.Head()
	if err != nil {
		panic(err)
	}

	if frame.FrameNumber > head.FrameNumber {
		e.dataTimeReel.Insert(frame, e.latestFrameReceived < frame.FrameNumber)
	}
	return nil
}