// creates and signs a record for the given key/value pair
func makeRecord(ps peer.Peerstore, p peer.ID, k key.Key, v []byte) (*pb.Record, error) {
	blob := bytes.Join([][]byte{[]byte(k), v, []byte(p)}, []byte{})
	sig, err := ps.PrivKey(p).Sign(blob)
	if err != nil {
		return nil, err
	}
	return &pb.Record{
		Key:       proto.String(string(k)),
		Value:     v,
		Author:    proto.String(string(p)),
		Signature: sig,
	}, nil
}

func storeProvidersToPeerstore(ps peer.Peerstore, p peer.ID, providers []*dhtpb.Message_Peer) {
	for _, provider := range providers {
		providerID := peer.ID(provider.GetId())
		if providerID != p {
			log.Errorf("provider message came from third-party %s", p)
			continue
		}
		for _, maddr := range provider.Addresses() {
			// as a router, we want to store addresses for peers who have provided
			ps.AddAddr(p, maddr, peer.AddressTTL)
		}
	}
}

func printPeer(ps peer.Peerstore, p peer.ID) (interface{}, error) {
	if p == "" {
		return nil, errors.New("Attempted to print nil peer!")
	}

	info := new(IdOutput)
	info.ID = p.Pretty()

	if pk := ps.PubKey(p); pk != nil {
		pkb, err := ic.MarshalPublicKey(pk)
		if err != nil {
			return nil, err
		}
		info.PublicKey = base64.StdEncoding.EncodeToString(pkb)
	}

	for _, a := range ps.Addrs(p) {
		info.Addresses = append(info.Addresses, a.String())
	}

	if v, err := ps.Get(p, "ProtocolVersion"); err == nil {
		if vs, ok := v.(string); ok {
			info.ProtocolVersion = vs
		}
	}
	if v, err := ps.Get(p, "AgentVersion"); err == nil {
		if vs, ok := v.(string); ok {
			info.AgentVersion = vs
		}
	}

	return info, nil
}

func verify(ps peer.Peerstore, r *dhtpb.Record) error {
	v := make(record.Validator)
	v["pk"] = record.PublicKeyValidator
	p := peer.ID(r.GetAuthor())
	pk := ps.PubKey(p)
	if pk == nil {
		return fmt.Errorf("do not have public key for %s", p)
	}
	if err := record.CheckRecordSig(r, pk); err != nil {
		return err
	}
	if err := v.VerifyRecord(r); err != nil {
		return err
	}
	return nil
}

// NewSwarm constructs a Swarm, with a Chan.
func NewSwarm(ctx context.Context, listenAddrs []ma.Multiaddr,
	local peer.ID, peers peer.Peerstore, bwc metrics.Reporter) (*Swarm, error) {

	listenAddrs, err := filterAddrs(listenAddrs)
	if err != nil {
		return nil, err
	}

	wrap := func(c transport.Conn) transport.Conn {
		return mconn.WrapConn(bwc, c)
	}

	s := &Swarm{
		swarm:  ps.NewSwarm(PSTransport),
		local:  local,
		peers:  peers,
		ctx:    ctx,
		dialT:  DialTimeout,
		notifs: make(map[inet.Notifiee]ps.Notifiee),
		transports: []transport.Transport{
			transport.NewTCPTransport(),
			transport.NewUtpTransport(),
		},
		bwc:         bwc,
		fdRateLimit: make(chan struct{}, concurrentFdDials),
		Filters:     filter.NewFilters(),
		dialer:      conn.NewDialer(local, peers.PrivKey(local), wrap),
	}

	// configure Swarm
	s.proc = goprocessctx.WithContextAndTeardown(ctx, s.teardown)
	s.SetConnHandler(nil) // make sure to setup our own conn handler.

	// setup swarm metrics
	prom.MustRegisterOrGet(peersTotal)
	s.Notify((*metricsNotifiee)(s))

	err = s.setupInterfaces(listenAddrs)
	if err != nil {
		return nil, err
	}

	return s, nil
}