// putProvider sends a message to peer 'p' saying that the local node
// can provide the value of 'key'
func (dht *IpfsDHT) putProvider(ctx context.Context, p peer.ID, skey string) error {

	// add self as the provider
	pi := peer.PeerInfo{
		ID:    dht.self,
		Addrs: dht.host.Addrs(),
	}

	// // only share WAN-friendly addresses ??
	// pi.Addrs = addrutil.WANShareableAddrs(pi.Addrs)
	if len(pi.Addrs) < 1 {
		// log.Infof("%s putProvider: %s for %s error: no wan-friendly addresses", dht.self, p, key.Key(key), pi.Addrs)
		return fmt.Errorf("no known addresses for self. cannot put provider.")
	}

	pmes := pb.NewMessage(pb.Message_ADD_PROVIDER, skey, 0)
	pmes.ProviderPeers = pb.RawPeerInfosToPBPeers([]peer.PeerInfo{pi})
	err := dht.sendMessage(ctx, p, pmes)
	if err != nil {
		return err
	}

	log.Debugf("%s putProvider: %s for %s (%s)", dht.self, p, key.Key(skey), pi.Addrs)
	return nil
}

// putValueToPeer stores the given key/value pair at the peer 'p'
func (dht *IpfsDHT) putValueToPeer(ctx context.Context, p peer.ID,
	key key.Key, rec *pb.Record) error {

	pmes := pb.NewMessage(pb.Message_PUT_VALUE, string(key), 0)
	pmes.Record = rec
	rpmes, err := dht.sendRequest(ctx, p, pmes)
	switch err {
	case ErrReadTimeout:
		log.Warningf("read timeout: %s %s", p.Pretty(), key)
		fallthrough
	default:
		return err
	case nil:
		break
	}

	if err != nil {
		return err
	}

	if !bytes.Equal(rpmes.GetRecord().Value, pmes.GetRecord().Value) {
		return errors.New("value not put correctly")
	}
	return nil
}

func (dht *IpfsDHT) handleFindPeer(ctx context.Context, p peer.ID, pmes *pb.Message) (*pb.Message, error) {
	defer log.EventBegin(ctx, "handleFindPeer", p).Done()
	resp := pb.NewMessage(pmes.GetType(), "", pmes.GetClusterLevel())
	var closest []peer.ID

	// if looking for self... special case where we send it on CloserPeers.
	if peer.ID(pmes.GetKey()) == dht.self {
		closest = []peer.ID{dht.self}
	} else {
		closest = dht.betterPeersToQuery(pmes, p, CloserPeerCount)
	}

	if closest == nil {
		log.Infof("%s handleFindPeer %s: could not find anything.", dht.self, p)
		return resp, nil
	}

	var withAddresses []peer.PeerInfo
	closestinfos := peer.PeerInfos(dht.peerstore, closest)
	for _, pi := range closestinfos {
		if len(pi.Addrs) > 0 {
			withAddresses = append(withAddresses, pi)
			log.Debugf("handleFindPeer: sending back '%s'", pi.ID)
		}
	}

	resp.CloserPeers = pb.PeerInfosToPBPeers(dht.host.Network(), withAddresses)
	return resp, nil
}

// getValueSingle simply performs the get value RPC with the given parameters
func (dht *IpfsDHT) getValueSingle(ctx context.Context, p peer.ID,
	key key.Key) (*pb.Message, error) {
	defer log.EventBegin(ctx, "getValueSingle", p, &key).Done()

	pmes := pb.NewMessage(pb.Message_GET_VALUE, string(key), 0)
	return dht.sendRequest(ctx, p, pmes)
}

func (c *Client) GetValue(ctx context.Context, k key.Key) ([]byte, error) {
	defer log.EventBegin(ctx, "getValue", &k).Done()
	msg := pb.NewMessage(pb.Message_GET_VALUE, string(k), 0)
	response, err := c.proxy.SendRequest(ctx, msg) // TODO wrap to hide the remote
	if err != nil {
		return nil, err
	}
	return response.Record.GetValue(), nil
}

func (c *Client) PutValue(ctx context.Context, k key.Key, v []byte) error {
	defer log.EventBegin(ctx, "putValue", &k).Done()
	r, err := makeRecord(c.peerstore, c.local, k, v)
	if err != nil {
		return err
	}
	pmes := pb.NewMessage(pb.Message_PUT_VALUE, string(k), 0)
	pmes.Record = r
	return c.proxy.SendMessage(ctx, pmes) // wrap to hide the remote
}

// Ping a peer, log the time it took
func (dht *IpfsDHT) Ping(ctx context.Context, p peer.ID) (time.Duration, error) {
	// Thoughts: maybe this should accept an ID and do a peer lookup?
	log.Debugf("ping %s start", p)
	before := time.Now()

	pmes := pb.NewMessage(pb.Message_PING, "", 0)
	_, err := dht.sendRequest(ctx, p, pmes)
	log.Debugf("ping %s end (err = %s)", p, err)

	return time.Now().Sub(before), err
}

func (c *Client) FindPeer(ctx context.Context, id peer.ID) (peer.PeerInfo, error) {
	defer log.EventBegin(ctx, "findPeer", id).Done()
	request := pb.NewMessage(pb.Message_FIND_NODE, string(id), 0)
	response, err := c.proxy.SendRequest(ctx, request) // hide remote
	if err != nil {
		return peer.PeerInfo{}, err
	}
	for _, p := range pb.PBPeersToPeerInfos(response.GetCloserPeers()) {
		if p.ID == id {
			return p, nil
		}
	}
	return peer.PeerInfo{}, errors.New("could not find peer")
}

// putValueToPeer stores the given key/value pair at the peer 'p'
func (dht *IpfsDHT) putValueToPeer(ctx context.Context, p peer.ID,
	key key.Key, rec *pb.Record) error {

	pmes := pb.NewMessage(pb.Message_PUT_VALUE, string(key), 0)
	pmes.Record = rec
	rpmes, err := dht.sendRequest(ctx, p, pmes)
	if err != nil {
		return err
	}

	if !bytes.Equal(rpmes.GetRecord().Value, pmes.GetRecord().Value) {
		return errors.New("value not put correctly")
	}
	return nil
}

func (dht *IpfsDHT) findProvidersSingle(ctx context.Context, p peer.ID, key key.Key) (*pb.Message, error) {
	defer log.EventBegin(ctx, "findProvidersSingle", p, &key).Done()

	pmes := pb.NewMessage(pb.Message_GET_PROVIDERS, string(key), 0)
	resp, err := dht.sendRequest(ctx, p, pmes)
	switch err {
	case nil:
		return resp, nil
	case ErrReadTimeout:
		log.Warningf("read timeout: %s %s", p.Pretty(), key)
		fallthrough
	default:
		return nil, err
	}
}

// findPeerSingle asks peer 'p' if they know where the peer with id 'id' is
func (dht *IpfsDHT) findPeerSingle(ctx context.Context, p peer.ID, id peer.ID) (*pb.Message, error) {
	defer log.EventBegin(ctx, "findPeerSingle", p, id).Done()

	pmes := pb.NewMessage(pb.Message_FIND_NODE, string(id), 0)
	resp, err := dht.sendRequest(ctx, p, pmes)
	switch err {
	case nil:
		return resp, nil
	case ErrReadTimeout:
		log.Warningf("read timeout: %s %s", p.Pretty(), id)
		fallthrough
	default:
		return nil, err
	}
}

func (c *Client) Provide(ctx context.Context, k key.Key) error {
	defer log.EventBegin(ctx, "provide", &k).Done()
	msg := pb.NewMessage(pb.Message_ADD_PROVIDER, string(k), 0)
	// FIXME how is connectedness defined for the local node
	pri := []pb.PeerRoutingInfo{
		{
			PeerInfo: peer.PeerInfo{
				ID:    c.local,
				Addrs: c.peerhost.Addrs(),
			},
		},
	}
	msg.ProviderPeers = pb.PeerRoutingInfosToPBPeers(pri)
	return c.proxy.SendMessage(ctx, msg) // TODO wrap to hide remote
}

func (dht *IpfsDHT) makeProvRecord(skey key.Key) (*pb.Message, error) {
	pi := pstore.PeerInfo{
		ID:    dht.self,
		Addrs: dht.host.Addrs(),
	}

	// // only share WAN-friendly addresses ??
	// pi.Addrs = addrutil.WANShareableAddrs(pi.Addrs)
	if len(pi.Addrs) < 1 {
		return nil, fmt.Errorf("no known addresses for self. cannot put provider.")
	}

	pmes := pb.NewMessage(pb.Message_ADD_PROVIDER, string(skey), 0)
	pmes.ProviderPeers = pb.RawPeerInfosToPBPeers([]pstore.PeerInfo{pi})
	return pmes, nil
}

func (dht *IpfsDHT) handleGetProviders(ctx context.Context, p peer.ID, pmes *pb.Message) (*pb.Message, error) {
	lm := make(lgbl.DeferredMap)
	lm["peer"] = func() interface{} { return p.Pretty() }
	defer log.EventBegin(ctx, "handleGetProviders", lm).Done()

	resp := pb.NewMessage(pmes.GetType(), pmes.GetKey(), pmes.GetClusterLevel())
	key := key.Key(pmes.GetKey())
	lm["key"] = func() interface{} { return key.Pretty() }

	// debug logging niceness.
	reqDesc := fmt.Sprintf("%s handleGetProviders(%s, %s): ", dht.self, p, key)
	log.Debugf("%s begin", reqDesc)
	defer log.Debugf("%s end", reqDesc)

	// check if we have this value, to add ourselves as provider.
	has, err := dht.datastore.Has(key.DsKey())
	if err != nil && err != ds.ErrNotFound {
		log.Debugf("unexpected datastore error: %v\n", err)
		has = false
	}

	// setup providers
	providers := dht.providers.GetProviders(ctx, key)
	if has {
		providers = append(providers, dht.self)
		log.Debugf("%s have the value. added self as provider", reqDesc)
	}

	if providers != nil && len(providers) > 0 {
		infos := peer.PeerInfos(dht.peerstore, providers)
		resp.ProviderPeers = pb.PeerInfosToPBPeers(dht.host.Network(), infos)
		log.Debugf("%s have %d providers: %s", reqDesc, len(providers), infos)
	}

	// Also send closer peers.
	closer := dht.betterPeersToQuery(pmes, p, CloserPeerCount)
	if closer != nil {
		infos := peer.PeerInfos(dht.peerstore, closer)
		resp.CloserPeers = pb.PeerInfosToPBPeers(dht.host.Network(), infos)
		log.Debugf("%s have %d closer peers: %s", reqDesc, len(closer), infos)
	}

	return resp, nil
}

func (dht *IpfsDHT) handleGetValue(ctx context.Context, p peer.ID, pmes *pb.Message) (*pb.Message, error) {
	defer log.EventBegin(ctx, "handleGetValue", p).Done()
	log.Debugf("%s handleGetValue for key: %s", dht.self, pmes.GetKey())

	// setup response
	resp := pb.NewMessage(pmes.GetType(), pmes.GetKey(), pmes.GetClusterLevel())

	// first, is there even a key?
	k := key.Key(pmes.GetKey())
	if k == "" {
		return nil, errors.New("handleGetValue but no key was provided")
		// TODO: send back an error response? could be bad, but the other node's hanging.
	}

	rec, err := dht.checkLocalDatastore(k)
	if err != nil {
		return nil, err
	}
	resp.Record = rec

	// Find closest peer on given cluster to desired key and reply with that info
	closer := dht.betterPeersToQuery(pmes, p, CloserPeerCount)
	if len(closer) > 0 {
		closerinfos := peer.PeerInfos(dht.peerstore, closer)
		for _, pi := range closerinfos {
			log.Debugf("handleGetValue returning closer peer: '%s'", pi.ID)
			if len(pi.Addrs) < 1 {
				log.Errorf(`no addresses on peer being sent!
					[local:%s]
					[sending:%s]
					[remote:%s]`, dht.self, pi.ID, p)
			}
		}

		resp.CloserPeers = pb.PeerInfosToPBPeers(dht.host.Network(), closerinfos)
	}

	return resp, nil
}

func (c *Client) FindProvidersAsync(ctx context.Context, k key.Key, max int) <-chan peer.PeerInfo {
	ctx = logging.ContextWithLoggable(ctx, logging.Uuid("findProviders"))
	defer log.EventBegin(ctx, "findProviders", &k).Done()
	ch := make(chan peer.PeerInfo)
	go func() {
		defer close(ch)
		request := pb.NewMessage(pb.Message_GET_PROVIDERS, string(k), 0)
		response, err := c.proxy.SendRequest(ctx, request)
		if err != nil {
			log.Debug(err)
			return
		}
		for _, p := range pb.PBPeersToPeerInfos(response.GetProviderPeers()) {
			select {
			case <-ctx.Done():
				log.Debug(ctx.Err())
				return
			case ch <- p:
			}
		}
	}()
	return ch
}

func (s *Server) handleMessage(
	ctx context.Context, p peer.ID, req *dhtpb.Message) (peer.ID, *dhtpb.Message) {

	defer log.EventBegin(ctx, "routingMessageReceived", req, p).Done()

	var response = dhtpb.NewMessage(req.GetType(), req.GetKey(), req.GetClusterLevel())
	switch req.GetType() {

	case dhtpb.Message_GET_VALUE:
		rawRecord, err := getRoutingRecord(s.routingBackend, key.Key(req.GetKey()))
		if err != nil {
			return "", nil
		}
		response.Record = rawRecord
		return p, response

	case dhtpb.Message_PUT_VALUE:
		// FIXME: verify complains that the peer's ID is not present in the
		// peerstore. Mocknet problem?
		// if err := verify(s.peerstore, req.GetRecord()); err != nil {
		// 	log.Event(ctx, "validationFailed", req, p)
		// 	return "", nil
		// }
		putRoutingRecord(s.routingBackend, key.Key(req.GetKey()), req.GetRecord())
		return p, req

	case dhtpb.Message_FIND_NODE:
		p := s.peerstore.PeerInfo(peer.ID(req.GetKey()))
		pri := []dhtpb.PeerRoutingInfo{
			{
				PeerInfo: p,
				// Connectedness: TODO
			},
		}
		response.CloserPeers = dhtpb.PeerRoutingInfosToPBPeers(pri)
		return p.ID, response

	case dhtpb.Message_ADD_PROVIDER:
		for _, provider := range req.GetProviderPeers() {
			providerID := peer.ID(provider.GetId())
			if providerID == p {
				store := []*dhtpb.Message_Peer{provider}
				storeProvidersToPeerstore(s.peerstore, p, store)
				if err := putRoutingProviders(s.routingBackend, key.Key(req.GetKey()), store); err != nil {
					return "", nil
				}
			} else {
				log.Event(ctx, "addProviderBadRequest", p, req)
			}
		}
		return "", nil

	case dhtpb.Message_GET_PROVIDERS:
		providers, err := getRoutingProviders(s.routingBackend, key.Key(req.GetKey()))
		if err != nil {
			return "", nil
		}
		response.ProviderPeers = providers
		return p, response

	case dhtpb.Message_PING:
		return p, req
	default:
	}
	return "", nil
}

// findPeerSingle asks peer 'p' if they know where the peer with id 'id' is
func (dht *IpfsDHT) findPeerSingle(ctx context.Context, p peer.ID, id peer.ID) (*pb.Message, error) {
	defer log.EventBegin(ctx, "findPeerSingle", p, id).Done()

	pmes := pb.NewMessage(pb.Message_FIND_NODE, string(id), 0)
	return dht.sendRequest(ctx, p, pmes)
}

func (dht *IpfsDHT) handleGetValue(ctx context.Context, p peer.ID, pmes *pb.Message) (*pb.Message, error) {
	defer log.EventBegin(ctx, "handleGetValue", p).Done()
	log.Debugf("%s handleGetValue for key: %s", dht.self, pmes.GetKey())

	// setup response
	resp := pb.NewMessage(pmes.GetType(), pmes.GetKey(), pmes.GetClusterLevel())

	// first, is there even a key?
	k := pmes.GetKey()
	if k == "" {
		return nil, errors.New("handleGetValue but no key was provided")
		// TODO: send back an error response? could be bad, but the other node's hanging.
	}

	// let's first check if we have the value locally.
	log.Debugf("%s handleGetValue looking into ds", dht.self)
	dskey := key.Key(k).DsKey()
	iVal, err := dht.datastore.Get(dskey)
	log.Debugf("%s handleGetValue looking into ds GOT %v", dht.self, iVal)

	// if we got an unexpected error, bail.
	if err != nil && err != ds.ErrNotFound {
		return nil, err
	}

	// if we have the value, send it back
	if err == nil {
		log.Debugf("%s handleGetValue success!", dht.self)

		byts, ok := iVal.([]byte)
		if !ok {
			return nil, fmt.Errorf("datastore had non byte-slice value for %v", dskey)
		}

		rec := new(pb.Record)
		err := proto.Unmarshal(byts, rec)
		if err != nil {
			log.Debug("Failed to unmarshal dht record from datastore")
			return nil, err
		}

		resp.Record = rec
	}

	// Find closest peer on given cluster to desired key and reply with that info
	closer := dht.betterPeersToQuery(pmes, p, CloserPeerCount)
	if len(closer) > 0 {
		closerinfos := peer.PeerInfos(dht.peerstore, closer)
		for _, pi := range closerinfos {
			log.Debugf("handleGetValue returning closer peer: '%s'", pi.ID)
			if len(pi.Addrs) < 1 {
				log.Errorf(`no addresses on peer being sent!
					[local:%s]
					[sending:%s]
					[remote:%s]`, dht.self, pi.ID, p)
			}
		}

		resp.CloserPeers = pb.PeerInfosToPBPeers(dht.host.Network(), closerinfos)
	}

	return resp, nil
}

func (dht *IpfsDHT) findProvidersSingle(ctx context.Context, p peer.ID, key key.Key) (*pb.Message, error) {
	defer log.EventBegin(ctx, "findProvidersSingle", p, &key).Done()

	pmes := pb.NewMessage(pb.Message_GET_PROVIDERS, string(key), 0)
	return dht.sendRequest(ctx, p, pmes)
}