package indexer

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"oc-discovery/daemons/node/common"
	"time"

	oclib "cloud.o-forge.io/core/oc-lib"
	pp "cloud.o-forge.io/core/oc-lib/models/peer"
	"cloud.o-forge.io/core/oc-lib/models/utils"
	"cloud.o-forge.io/core/oc-lib/tools"
	"github.com/libp2p/go-libp2p/core/crypto"
	"github.com/libp2p/go-libp2p/core/network"
	"github.com/libp2p/go-libp2p/core/peer"
)

type PeerRecord struct {
	Name          string    `json:"name"`
	DID           string    `json:"did"` // real PEER ID
	PeerID        string    `json:"peer_id"`
	PubKey        []byte    `json:"pub_key"`
	APIUrl        string    `json:"api_url"`
	StreamAddress string    `json:"stream_address"`
	NATSAddress   string    `json:"nats_address"`
	WalletAddress string    `json:"wallet_address"`
	Signature     []byte    `json:"signature"`
	ExpiryDate    time.Time `json:"expiry_date"`
}

func (p *PeerRecord) Sign() error {
	priv, err := tools.LoadKeyFromFilePrivate()
	if err != nil {
		return err
	}
	dht := PeerRecord{
		Name:       p.Name,
		DID:        p.DID,
		PubKey:     p.PubKey,
		ExpiryDate: p.ExpiryDate,
	}
	payload, _ := json.Marshal(dht)
	b, err := common.Sign(priv, payload)
	p.Signature = b
	return err
}

func (p *PeerRecord) Verify() (crypto.PubKey, error) {
	pubKey, err := crypto.UnmarshalPublicKey(p.PubKey) // retrieve pub key in message
	if err != nil {
		fmt.Println("UnmarshalPublicKey")
		return pubKey, err
	}
	dht := PeerRecord{
		Name:       p.Name,
		DID:        p.DID,
		PubKey:     p.PubKey,
		ExpiryDate: p.ExpiryDate,
	}
	payload, _ := json.Marshal(dht)

	if ok, _ := common.Verify(pubKey, payload, p.Signature); !ok { // verify minimal message was sign per pubKey
		fmt.Println("Verify")
		return pubKey, errors.New("invalid signature")
	}
	return pubKey, nil
}

func (pr *PeerRecord) ExtractPeer(ourkey string, key string, pubKey crypto.PubKey) (bool, *pp.Peer, error) {
	pubBytes, err := crypto.MarshalPublicKey(pubKey)
	if err != nil {
		return false, nil, err
	}
	rel := pp.NONE
	if ourkey == key { // at this point is PeerID is same as our... we are... thats our peer INFO
		rel = pp.SELF
	}

	p := &pp.Peer{
		AbstractObject: utils.AbstractObject{
			UUID: pr.DID,
			Name: pr.Name,
		},
		Relation:      rel, // VERIFY.... it crush nothing
		PeerID:        pr.PeerID,
		PublicKey:     base64.StdEncoding.EncodeToString(pubBytes),
		APIUrl:        pr.APIUrl,
		StreamAddress: pr.StreamAddress,
		NATSAddress:   pr.NATSAddress,
		WalletAddress: pr.WalletAddress,
	}
	b, err := json.Marshal(p)
	if err != nil {
		return pp.SELF == p.Relation, nil, err
	}

	if time.Now().UTC().After(pr.ExpiryDate) {
		return pp.SELF == p.Relation, nil, errors.New("peer " + key + " is offline")
	}
	go tools.NewNATSCaller().SetNATSPub(tools.CREATE_RESOURCE, tools.NATSResponse{
		FromApp:    "oc-discovery",
		Datatype:   tools.PEER,
		Method:     int(tools.CREATE_RESOURCE),
		SearchAttr: "peer_id",
		Payload:    b,
	})

	return pp.SELF == p.Relation, p, nil
}

type GetValue struct {
	Key    string  `json:"key"`
	PeerID peer.ID `json:"peer_id"`
}

type GetResponse struct {
	Found   bool                  `json:"found"`
	Records map[string]PeerRecord `json:"records,omitempty"`
}

func (ix *IndexerService) genKey(did string) string {
	return "/node/" + did
}

func (ix *IndexerService) initNodeHandler() {
	ix.Host.SetStreamHandler(common.ProtocolHeartbeat, ix.HandleNodeHeartbeat)
	ix.Host.SetStreamHandler(common.ProtocolPublish, ix.handleNodePublish)
	ix.Host.SetStreamHandler(common.ProtocolGet, ix.handleNodeGet)
}

func (ix *IndexerService) handleNodePublish(s network.Stream) {
	defer s.Close()
	logger := oclib.GetLogger()
	for {
		var rec PeerRecord
		if err := json.NewDecoder(s).Decode(&rec); err != nil {
			logger.Err(err)
			continue
		}
		rec2 := PeerRecord{
			Name:   rec.Name,
			DID:    rec.DID, // REAL PEER ID
			PubKey: rec.PubKey,
			PeerID: rec.PeerID,
		}
		if _, err := rec2.Verify(); err != nil {
			logger.Err(err)
			continue
		}
		if rec.PeerID == "" || rec.ExpiryDate.Before(time.Now().UTC()) { // already expired
			logger.Err(errors.New(rec.PeerID + " is expired."))
			continue
		}
		pid, err := peer.Decode(rec.PeerID)
		if err != nil {
			continue
		}

		ix.StreamMU.Lock()

		if ix.StreamRecords[common.ProtocolHeartbeat] == nil {
			ix.StreamRecords[common.ProtocolHeartbeat] = map[peer.ID]*common.StreamRecord[PeerRecord]{}
		}
		streams := ix.StreamRecords[common.ProtocolHeartbeat]

		if srec, ok := streams[pid]; ok {
			srec.DID = rec.DID
			srec.Record = rec
			srec.HeartbeatStream.UptimeTracker.LastSeen = time.Now().UTC()
		} else {
			ix.StreamMU.Unlock()
			logger.Err(errors.New("no heartbeat"))
			continue
		}
		ix.StreamMU.Unlock()

		key := ix.genKey(rec.DID)

		data, err := json.Marshal(rec)
		if err != nil {
			logger.Err(err)
			continue
		}

		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		if err := ix.DHT.PutValue(ctx, key, data); err != nil {
			logger.Err(err)
			cancel()
			continue
		}
		cancel()
		break // response... so quit
	}
}

func (ix *IndexerService) handleNodeGet(s network.Stream) {
	defer s.Close()
	logger := oclib.GetLogger()
	for {
		var req GetValue
		if err := json.NewDecoder(s).Decode(&req); err != nil {
			logger.Err(err)
			continue
		}
		ix.StreamMU.Lock()

		if ix.StreamRecords[common.ProtocolHeartbeat] == nil {
			ix.StreamRecords[common.ProtocolHeartbeat] = map[peer.ID]*common.StreamRecord[PeerRecord]{}
		}
		resp := GetResponse{
			Found:   false,
			Records: map[string]PeerRecord{},
		}
		streams := ix.StreamRecords[common.ProtocolHeartbeat]

		key := ix.genKey(req.Key)
		// simple lookup by PeerID (or DID)
		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		recBytes, err := ix.DHT.SearchValue(ctx, key)
		if err != nil {
			logger.Err(err).Msg("Failed to fetch PeerRecord from DHT")
			cancel()
		}
		cancel()
		for c := range recBytes {
			var rec PeerRecord
			if err := json.Unmarshal(c, &rec); err != nil || rec.PeerID != req.PeerID.String() {
				continue
			}
			resp.Found = true
			resp.Records[rec.PeerID] = rec
			if srec, ok := streams[req.PeerID]; ok {
				srec.DID = rec.DID
				srec.Record = rec
				srec.HeartbeatStream.UptimeTracker.LastSeen = time.Now().UTC()
			}
		}
		// Not found
		_ = json.NewEncoder(s).Encode(resp)
		ix.StreamMU.Unlock()
		break // response... so quit
	}
}