package node

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"oc-discovery/conf"
	"oc-discovery/daemons/node/common"
	"oc-discovery/daemons/node/indexer"
	"oc-discovery/daemons/node/pubsub"
	"oc-discovery/daemons/node/stream"
	"sync"
	"time"

	oclib "cloud.o-forge.io/core/oc-lib"
	"cloud.o-forge.io/core/oc-lib/dbs"
	"cloud.o-forge.io/core/oc-lib/models/peer"
	"cloud.o-forge.io/core/oc-lib/tools"
	"github.com/google/uuid"
	"github.com/libp2p/go-libp2p"
	pubsubs "github.com/libp2p/go-libp2p-pubsub"
	"github.com/libp2p/go-libp2p/core/crypto"
	"github.com/libp2p/go-libp2p/core/network"
	pp "github.com/libp2p/go-libp2p/core/peer"
	"github.com/libp2p/go-libp2p/core/protocol"
	"github.com/libp2p/go-libp2p/p2p/security/noise"
)

// activeSearch tracks an in-flight distributed peer search for one user.
type activeSearch struct {
	queryID string
	cancel  context.CancelFunc
}

type Node struct {
	*common.LongLivedStreamRecordedService[interface{}] // change type of stream
	PS                                                  *pubsubs.PubSub
	IndexerService                                      *indexer.IndexerService
	PubSubService                                       *pubsub.PubSubService
	StreamService                                       *stream.StreamService
	PeerID                                              pp.ID
	isIndexer                                           bool
	peerRecord                                          *indexer.PeerRecord

	// activeSearches: one streaming search per user; new search cancels previous.
	activeSearchesMu sync.Mutex
	activeSearches   map[string]*activeSearch

	Mu sync.RWMutex
}

func InitNode(isNode bool, isIndexer bool) (*Node, error) {
	if !isNode && !isIndexer {
		return nil, errors.New("wait... what ? your node need to  at least something. Retry we can't be friend in that case")
	}
	logger := oclib.GetLogger()
	logger.Info().Msg("retrieving private key...")
	priv, err := tools.LoadKeyFromFilePrivate() // your node private key
	if err != nil {
		return nil, err
	}
	logger.Info().Msg("retrieving psk file...")
	psk, err := common.LoadPSKFromFile() // network common private Network. Public OC PSK is Public Network
	if err != nil {
		return nil, nil
	}
	logger.Info().Msg("open a host...")
	gater := newOCConnectionGater(nil) // host set below after creation
	h, err := libp2p.New(
		libp2p.PrivateNetwork(psk),
		libp2p.Identity(priv),
		libp2p.Security(noise.ID, noise.New),
		libp2p.ListenAddrStrings(
			fmt.Sprintf("/ip4/0.0.0.0/tcp/%d", conf.GetConfig().NodeEndpointPort),
		),
		libp2p.ConnectionGater(gater),
	)
	gater.host = h // wire host back into gater now that it exists
	logger.Info().Msg("Host open on " + h.ID().String())
	if err != nil {
		return nil, errors.New("no host no node")
	}
	node := &Node{
		PeerID:                         h.ID(),
		isIndexer:                      isIndexer,
		LongLivedStreamRecordedService: common.NewStreamRecordedService[interface{}](h, 1000),
		activeSearches:                 map[string]*activeSearch{},
	}
	// Register the bandwidth probe handler so any peer measuring this node's
	// throughput can open a dedicated probe stream and read the echo.
	h.SetStreamHandler(common.ProtocolBandwidthProbe, common.HandleBandwidthProbe)
	// Register the witness query handler so peers can ask this node's view of indexers.
	h.SetStreamHandler(common.ProtocolWitnessQuery, func(s network.Stream) {
		common.HandleWitnessQuery(h, s)
	})
	var ps *pubsubs.PubSub
	if isNode {
		logger.Info().Msg("generate opencloud node...")
		ps, err = pubsubs.NewGossipSub(context.Background(), node.Host)
		if err != nil {
			panic(err) // can't run your node without a propalgation pubsub, of state of node.
		}
		node.PS = ps
		// buildRecord returns a fresh signed PeerRecord as JSON, embedded in each
		// heartbeat so the receiving indexer can republish it to the DHT directly.
		// peerRecord is nil until claimInfo runs, so the first ~20s heartbeats carry
		// no record — that's fine, claimInfo publishes once synchronously at startup.
		buildRecord := func() json.RawMessage {
			if node.peerRecord == nil {
				return nil
			}
			priv, err := tools.LoadKeyFromFilePrivate()
			if err != nil {
				return nil
			}
			fresh := *node.peerRecord
			fresh.PeerRecordPayload.ExpiryDate = time.Now().UTC().Add(2 * time.Minute)
			payload, _ := json.Marshal(fresh.PeerRecordPayload)
			fresh.Signature, err = priv.Sign(payload)
			if err != nil {
				return nil
			}
			b, _ := json.Marshal(fresh)
			return json.RawMessage(b)
		}
		logger.Info().Msg("connect to indexers...")
		common.ConnectToIndexers(node.Host, conf.GetConfig().MinIndexer, conf.GetConfig().MaxIndexer, buildRecord)
		logger.Info().Msg("claims my node...")
		if _, err := node.claimInfo(conf.GetConfig().Name, conf.GetConfig().Hostname); err != nil {
			panic(err)
		}
		logger.Info().Msg("run garbage collector...")
		node.StartGC(30 * time.Second)

		if node.StreamService, err = stream.InitStream(context.Background(), node.Host, node.PeerID, 1000, node); err != nil {
			panic(err)
		}

		if node.PubSubService, err = pubsub.InitPubSub(context.Background(), node.Host, node.PS, node, node.StreamService); err != nil {
			panic(err)
		}
		f := func(ctx context.Context, evt common.Event, topic string) {
			m := map[string]interface{}{}
			err := json.Unmarshal(evt.Payload, &m)
			if err != nil || evt.From == node.PeerID.String() {
				return
			}
			if p, err := node.GetPeerRecord(ctx, evt.From, false); err == nil && len(p) > 0 && m["search"] != nil {
				node.StreamService.SendResponse(p[0], &evt, fmt.Sprintf("%v", m["search"]))
			}
		}
		logger.Info().Msg("subscribe to decentralized search flow...")
		node.SubscribeToSearch(node.PS, &f)
		logger.Info().Msg("connect to NATS")
		go ListenNATS(node)
		logger.Info().Msg("Node is actually running.")
	}
	if isIndexer {
		logger.Info().Msg("generate opencloud indexer...")
		node.IndexerService = indexer.NewIndexerService(node.Host, ps, 500)
	}
	return node, nil
}

func (d *Node) Close() {
	if d.isIndexer && d.IndexerService != nil {
		d.IndexerService.Close()
	}
	d.PubSubService.Close()
	d.StreamService.Close()
	d.Host.Close()
}

func (d *Node) publishPeerRecord(
	rec *indexer.PeerRecord,
) error {
	priv, err := tools.LoadKeyFromFilePrivate() // your node private key
	if err != nil {
		return err
	}

	for _, ad := range common.Indexers.GetAddrs() {
		var err error
		if common.Indexers.Streams, err = common.TempStream(d.Host, *ad.Info, common.ProtocolPublish, "", common.Indexers.Streams, map[protocol.ID]*common.ProtocolInfo{},
			&common.Indexers.MuStream); err != nil {
			continue
		}
		stream := common.Indexers.Streams.GetPerID(common.ProtocolPublish, ad.Info.ID)
		base := indexer.PeerRecordPayload{
			Name:       rec.Name,
			DID:        rec.DID,
			PubKey:     rec.PubKey,
			ExpiryDate: time.Now().UTC().Add(2 * time.Minute),
		}
		payload, _ := json.Marshal(base)
		rec.PeerRecordPayload = base
		rec.Signature, err = priv.Sign(payload)
		if err := json.NewEncoder(stream.Stream).Encode(&rec); err != nil { // then publish on stream
			return err
		}
	}
	return nil
}

// SearchPeerRecord starts a distributed peer search via ProtocolSearchPeer.
// userKey identifies the requesting user — a new call cancels any previous
// search for the same user. Results are pushed to onResult as they arrive.
// The function returns when the search stream closes (idle timeout or indexer unreachable).
func (d *Node) SearchPeerRecord(userKey, needle string, onResult func(common.SearchHit)) {
	logger := oclib.GetLogger()

	ctx, cancel := context.WithCancel(context.Background())

	d.activeSearchesMu.Lock()
	if prev, ok := d.activeSearches[userKey]; ok {
		prev.cancel()
	}
	queryID := uuid.New().String()
	d.activeSearches[userKey] = &activeSearch{queryID: queryID, cancel: cancel}
	d.activeSearchesMu.Unlock()

	defer func() {
		cancel()
		d.activeSearchesMu.Lock()
		if cur, ok := d.activeSearches[userKey]; ok && cur.queryID == queryID {
			delete(d.activeSearches, userKey)
		}
		d.activeSearchesMu.Unlock()
	}()

	req := common.SearchPeerRequest{QueryID: queryID}
	if pid, err := pp.Decode(needle); err == nil {
		req.PeerID = pid.String()
	} else if _, err := uuid.Parse(needle); err == nil {
		req.DID = needle
	} else {
		req.Name = needle
	}

	// Try indexers in pool order until one accepts the stream.
	for _, ad := range common.Indexers.GetAddrs() {
		if ad.Info == nil {
			continue
		}
		dialCtx, dialCancel := context.WithTimeout(ctx, 5*time.Second)
		s, err := d.Host.NewStream(dialCtx, ad.Info.ID, common.ProtocolSearchPeer)
		dialCancel()
		if err != nil {
			continue
		}
		if err := json.NewEncoder(s).Encode(req); err != nil {
			s.Reset()
			continue
		}
		dec := json.NewDecoder(s)
		for {
			var result common.SearchPeerResult
			if err := dec.Decode(&result); err != nil {
				break
			}
			if result.QueryID != queryID {
				continue // stale response from a previous query
			}
			for _, hit := range result.Records {
				onResult(hit)
			}
		}
		s.Reset()
		return
	}
	logger.Warn().Str("user", userKey).Msg("[search] no reachable indexer for peer search")
}

func (d *Node) GetPeerRecord(
	ctx context.Context,
	pidOrdid string,
	search bool,
) ([]*peer.Peer, error) {
	var err error
	var info map[string]indexer.PeerRecord
	// Build the GetValue request: if pidOrdid is neither a UUID DID nor a libp2p
	// PeerID, treat it as a human-readable name and let the indexer resolve it.
	getReq := indexer.GetValue{Key: pidOrdid}
	if pidR, pidErr := pp.Decode(pidOrdid); pidErr == nil {
		getReq.PeerID = pidR.String()
	} else if _, uuidErr := uuid.Parse(pidOrdid); uuidErr != nil {
		// Not a UUID DID → treat pidOrdid as a name substring search.
		getReq.Name = pidOrdid
		getReq.Key = ""
	}
	getReq.Search = search
	for _, ad := range common.Indexers.GetAddrs() {
		if common.Indexers.Streams, err = common.TempStream(d.Host, *ad.Info, common.ProtocolGet, "",
			common.Indexers.Streams, map[protocol.ID]*common.ProtocolInfo{}, &common.Indexers.MuStream); err != nil {
			continue
		}
		stream := common.Indexers.Streams.GetPerID(common.ProtocolGet, ad.Info.ID)
		if err := json.NewEncoder(stream.Stream).Encode(getReq); err != nil {
			continue
		}
		var resp indexer.GetResponse
		if err := json.NewDecoder(stream.Stream).Decode(&resp); err != nil {
			continue
		}
		if resp.Found {
			info = resp.Records
		}
		break
	}
	var ps []*peer.Peer
	for _, pr := range info {
		if pk, err := pr.Verify(); err != nil {
			return nil, err
		} else if _, p, err := pr.ExtractPeer(d.PeerID.String(), pr.PeerID, pk); err != nil {
			return nil, err
		} else {
			ps = append(ps, p)
		}
	}

	return ps, err
}

func (d *Node) claimInfo(
	name string,
	endPoint string, // TODO : endpoint is not necesserry StreamAddress
) (*peer.Peer, error) {
	if endPoint == "" {
		return nil, errors.New("no endpoint found for peer")
	}
	did := uuid.New().String()

	peers := oclib.NewRequestAdmin(oclib.LibDataEnum(oclib.PEER), nil).Search(&dbs.Filters{
		And: map[string][]dbs.Filter{ // search by name if no filters are provided
			"peer_id": {{Operator: dbs.EQUAL.String(), Value: d.Host.ID().String()}},
		},
	}, "", false)
	if len(peers.Data) > 0 {
		did = peers.Data[0].GetID() // if already existing set up did as made
	}
	priv, err := tools.LoadKeyFromFilePrivate()
	if err != nil {
		return nil, err
	}
	pub, err := tools.LoadKeyFromFilePublic()
	if err != nil {
		return nil, err
	}
	pubBytes, err := crypto.MarshalPublicKey(pub)
	if err != nil {
		return nil, err
	}

	now := time.Now().UTC()
	expiry := now.Add(150 * time.Second)

	pRec := indexer.PeerRecordPayload{
		Name:       name,
		DID:        did, // REAL PEER ID
		PubKey:     pubBytes,
		ExpiryDate: expiry,
	}
	d.PeerID = d.Host.ID()
	payload, _ := json.Marshal(pRec)

	rec := &indexer.PeerRecord{
		PeerRecordPayload: pRec,
	}
	rec.Signature, err = priv.Sign(payload)
	if err != nil {
		return nil, err
	}
	rec.PeerID = d.Host.ID().String()
	rec.APIUrl = endPoint
	rec.StreamAddress = "/ip4/" + conf.GetConfig().Hostname + "/tcp/" + fmt.Sprintf("%v", conf.GetConfig().NodeEndpointPort) + "/p2p/" + rec.PeerID
	rec.NATSAddress = oclib.GetConfig().NATSUrl
	rec.WalletAddress = "my-wallet"

	if err := d.publishPeerRecord(rec); err != nil {
		return nil, err
	}
	d.peerRecord = rec
	if _, err := rec.Verify(); err != nil {
		return nil, err
	} else {
		_, p, err := rec.ExtractPeer(did, did, pub)
		b, err := json.Marshal(p)
		if err != nil {
			return p, err
		}
		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 p, err
	}
}

/*
TODO:
- Le booking est un flow neuf décentralisé :
 On check on attend une réponse, on valide, il passe par discovery, on relais.
- Le shared workspace est une affaire de décentralisation,
	on communique avec les shared les mouvements
- Un shared remplace la notion de partnership à l'échelle de partnershipping
	-> quand on share un workspace on devient partenaire temporaire
		qu'on le soit originellement ou non.
	-> on a alors les mêmes privilèges.
- Les orchestrations admiralty ont le même fonctionnement.
	Un evenement provoque alors une création de clé de service.

On doit pouvoir crud avec verification de signature un DBobject.
*/