func (dht *IpfsDHT) handleGetProviders(p peer.Peer, pmes *pb.Message) (*pb.Message, error) {
	resp := pb.NewMessage(pmes.GetType(), pmes.GetKey(), pmes.GetClusterLevel())

	// check if we have this value, to add ourselves as provider.
	log.Debugf("handling GetProviders: '%s'", u.Key(pmes.GetKey()))
	dsk := u.Key(pmes.GetKey()).DsKey()
	has, err := dht.datastore.Has(dsk)
	if err != nil && err != ds.ErrNotFound {
		log.Errorf("unexpected datastore error: %v\n", err)
		has = false
	}

	// setup providers
	providers := dht.providers.GetProviders(u.Key(pmes.GetKey()))
	if has {
		providers = append(providers, dht.self)
	}

	// if we've got providers, send thos those.
	if providers != nil && len(providers) > 0 {
		resp.ProviderPeers = pb.PeersToPBPeers(providers)
	}

	// Also send closer peers.
	closer := dht.betterPeersToQuery(pmes, CloserPeerCount)
	if closer != nil {
		resp.CloserPeers = pb.PeersToPBPeers(closer)
	}

	return resp, nil
}

func TestToNetFromNetPreservesWantList(t *testing.T) {
	original := New()
	original.AddWanted(u.Key("M"))
	original.AddWanted(u.Key("B"))
	original.AddWanted(u.Key("D"))
	original.AddWanted(u.Key("T"))
	original.AddWanted(u.Key("F"))

	p := peer.WithIDString("X")
	netmsg, err := original.ToNet(p)
	if err != nil {
		t.Fatal(err)
	}

	copied, err := FromNet(netmsg)
	if err != nil {
		t.Fatal(err)
	}

	keys := make(map[u.Key]bool)
	for _, k := range copied.Wantlist() {
		keys[k] = true
	}

	for _, k := range original.Wantlist() {
		if _, ok := keys[k]; !ok {
			t.Fatalf("Key Missing: \"%v\"", k)
		}
	}
}

func TestClientFindProviders(t *testing.T) {
	peer := peer.WithIDString("42")
	rs := VirtualRoutingServer()
	client := rs.Client(peer)

	k := u.Key("hello")
	err := client.Provide(context.Background(), k)
	if err != nil {
		t.Fatal(err)
	}
	max := 100

	providersFromHashTable := rs.Providers(k)

	isInHT := false
	for _, p := range providersFromHashTable {
		if bytes.Equal(p.ID(), peer.ID()) {
			isInHT = true
		}
	}
	if !isInHT {
		t.Fatal("Despite client providing key, peer wasn't in hash table as a provider")
	}
	providersFromClient := client.FindProvidersAsync(context.Background(), u.Key("hello"), max)
	isInClient := false
	for p := range providersFromClient {
		if bytes.Equal(p.ID(), peer.ID()) {
			isInClient = true
		}
	}
	if !isInClient {
		t.Fatal("Despite client providing key, client didn't receive peer when finding providers")
	}
}

func TestProvides(t *testing.T) {
	// t.Skip("skipping test to debug another")
	ctx := context.Background()

	u.Debug = false

	_, peers, dhts := setupDHTS(ctx, 4, t)
	defer func() {
		for i := 0; i < 4; i++ {
			dhts[i].Close()
			defer dhts[i].dialer.(inet.Network).Close()
		}
	}()

	_, err := dhts[0].Connect(ctx, peers[1])
	if err != nil {
		t.Fatal(err)
	}

	_, err = dhts[1].Connect(ctx, peers[2])
	if err != nil {
		t.Fatal(err)
	}

	_, err = dhts[1].Connect(ctx, peers[3])
	if err != nil {
		t.Fatal(err)
	}

	err = dhts[3].putLocal(u.Key("hello"), []byte("world"))
	if err != nil {
		t.Fatal(err)
	}

	bits, err := dhts[3].getLocal(u.Key("hello"))
	if err != nil && bytes.Equal(bits, []byte("world")) {
		t.Fatal(err)
	}

	err = dhts[3].Provide(ctx, u.Key("hello"))
	if err != nil {
		t.Fatal(err)
	}

	time.Sleep(time.Millisecond * 60)

	ctxT, _ := context.WithTimeout(ctx, time.Second)
	provchan := dhts[0].FindProvidersAsync(ctxT, u.Key("hello"), 1)

	after := time.After(time.Second)
	select {
	case prov := <-provchan:
		if prov == nil {
			t.Fatal("Got back nil provider")
		}
	case <-after:
		t.Fatal("Did not get a provider back.")
	}
}

func TestLayeredGet(t *testing.T) {
	if testing.Short() {
		t.SkipNow()
	}

	ctx := context.Background()
	u.Debug = false
	_, peers, dhts := setupDHTS(ctx, 4, t)
	defer func() {
		for i := 0; i < 4; i++ {
			dhts[i].Close()
			defer dhts[i].dialer.(inet.Network).Close()
		}
	}()

	_, err := dhts[0].Connect(ctx, peers[1])
	if err != nil {
		t.Fatalf("Failed to connect: %s", err)
	}

	_, err = dhts[1].Connect(ctx, peers[2])
	if err != nil {
		t.Fatal(err)
	}

	_, err = dhts[1].Connect(ctx, peers[3])
	if err != nil {
		t.Fatal(err)
	}

	err = dhts[3].putLocal(u.Key("/v/hello"), []byte("world"))
	if err != nil {
		t.Fatal(err)
	}

	err = dhts[3].Provide(ctx, u.Key("/v/hello"))
	if err != nil {
		t.Fatal(err)
	}

	time.Sleep(time.Millisecond * 60)

	ctxT, _ := context.WithTimeout(ctx, time.Second)
	val, err := dhts[0].GetValue(ctxT, u.Key("/v/hello"))
	if err != nil {
		t.Fatal(err)
	}

	if string(val) != "world" {
		t.Fatal("Got incorrect value.")
	}

}

// Resolve implements Resolver. Uses the IPFS routing system to resolve SFS-like
// names.
func (r *routingResolver) Resolve(name string) (string, error) {
	log.Debugf("RoutingResolve: '%s'", name)
	ctx := context.TODO()
	hash, err := mh.FromB58String(name)
	if err != nil {
		log.Warning("RoutingResolve: bad input hash: [%s]\n", name)
		return "", err
	}
	// name should be a multihash. if it isn't, error out here.

	// use the routing system to get the name.
	// /ipns/<name>
	h := []byte("/ipns/" + string(hash))

	ipnsKey := u.Key(h)
	val, err := r.routing.GetValue(ctx, ipnsKey)
	if err != nil {
		log.Warning("RoutingResolve get failed.")
		return "", err
	}

	entry := new(pb.IpnsEntry)
	err = proto.Unmarshal(val, entry)
	if err != nil {
		return "", err
	}

	// name should be a public key retrievable from ipfs
	// /ipfs/<name>
	key := u.Key("/pk/" + string(hash))
	pkval, err := r.routing.GetValue(ctx, key)
	if err != nil {
		log.Warning("RoutingResolve PubKey Get failed.")
		return "", err
	}

	// get PublicKey from node.Data
	pk, err := ci.UnmarshalPublicKey(pkval)
	if err != nil {
		return "", err
	}
	hsh, _ := pk.Hash()
	log.Debugf("pk hash = %s", u.Key(hsh))

	// check sig with pk
	if ok, err := pk.Verify(ipnsEntryDataForSig(entry), entry.GetSignature()); err != nil || !ok {
		return "", fmt.Errorf("Invalid value. Not signed by PrivateKey corresponding to %v", pk)
	}

	// ok sig checks out. this is a valid name.
	return string(entry.GetValue()), nil
}

func (dht *IpfsDHT) handleAddProvider(p peer.Peer, pmes *pb.Message) (*pb.Message, error) {
	key := u.Key(pmes.GetKey())

	log.Debugf("%s adding %s as a provider for '%s'\n", dht.self, p, peer.ID(key))

	// add provider should use the address given in the message
	for _, pb := range pmes.GetProviderPeers() {
		pid := peer.ID(pb.GetId())
		if pid.Equal(p.ID()) {

			addr, err := pb.Address()
			if err != nil {
				log.Errorf("provider %s error with address %s", p, *pb.Addr)
				continue
			}

			log.Infof("received provider %s %s for %s", p, addr, key)
			p.AddAddress(addr)
			dht.providers.AddProvider(key, p)

		} else {
			log.Errorf("handleAddProvider received provider %s from %s", pid, p)
		}
	}

	return pmes, nil // send back same msg as confirmation.
}

// betterPeerToQuery returns nearestPeersToQuery, but iff closer than self.
func (dht *IpfsDHT) betterPeersToQuery(pmes *pb.Message, count int) []peer.Peer {
	closer := dht.nearestPeersToQuery(pmes, count)

	// no node? nil
	if closer == nil {
		return nil
	}

	// == to self? thats bad
	for _, p := range closer {
		if p.ID().Equal(dht.self.ID()) {
			log.Error("Attempted to return self! this shouldnt happen...")
			return nil
		}
	}

	var filtered []peer.Peer
	for _, p := range closer {
		// must all be closer than self
		key := u.Key(pmes.GetKey())
		if !kb.Closer(dht.self.ID(), p.ID(), key) {
			filtered = append(filtered, p)
		}
	}

	// ok seems like closer nodes
	return filtered
}

// ResolvePath fetches the node for given path. It uses the first
// path component as a hash (key) of the first node, then resolves
// all other components walking the links, with ResolveLinks.
func (s *Resolver) ResolvePath(fpath string) (*merkledag.Node, error) {
	log.Debugf("Resolve: '%s'", fpath)
	fpath = path.Clean(fpath)

	parts := strings.Split(fpath, "/")

	// skip over empty first elem
	if len(parts[0]) == 0 {
		parts = parts[1:]
	}

	// if nothing, bail.
	if len(parts) == 0 {
		return nil, fmt.Errorf("ipfs path must contain at least one component")
	}

	// first element in the path is a b58 hash (for now)
	h, err := mh.FromB58String(parts[0])
	if err != nil {
		log.Debug("given path element is not a base58 string.\n")
		return nil, err
	}

	log.Debug("Resolve dag get.\n")
	nd, err := s.DAG.Get(u.Key(h))
	if err != nil {
		return nil, err
	}

	return s.ResolveLinks(nd, parts[1:])
}

func TestClientOverMax(t *testing.T) {
	rs := VirtualRoutingServer()
	k := u.Key("hello")
	numProvidersForHelloKey := 100
	for i := 0; i < numProvidersForHelloKey; i++ {
		peer := peer.WithIDString(string(i))
		err := rs.Announce(peer, k)
		if err != nil {
			t.Fatal(err)
		}
	}
	providersFromHashTable := rs.Providers(k)
	if len(providersFromHashTable) != numProvidersForHelloKey {
		t.Log(1 == len(providersFromHashTable))
		t.Fatal("not all providers were returned")
	}

	max := 10
	peer := peer.WithIDString("TODO")
	client := rs.Client(peer)

	providersFromClient := client.FindProvidersAsync(context.Background(), k, max)
	i := 0
	for _ = range providersFromClient {
		i++
	}
	if i != max {
		t.Fatal("Too many providers returned")
	}
}

// GetNode returns the MDAG Node that this link points to
func (l *Link) GetNode(serv DAGService) (*Node, error) {
	if l.Node != nil {
		return l.Node, nil
	}

	return serv.Get(u.Key(l.Hash))
}

func (p *peerstore) Delete(i ID) error {
	p.Lock()
	defer p.Unlock()

	k := u.Key(i).DsKey()
	return p.peers.Delete(k)
}

func TestKeyNotFound(t *testing.T) {

	vrs := VirtualRoutingServer()
	empty := vrs.Providers(u.Key("not there"))
	if len(empty) != 0 {
		t.Fatal("should be empty")
	}
}

// ID returns the ID of a given Conn.
func ID(c Conn) string {
	l := fmt.Sprintf("%s/%s", c.LocalMultiaddr(), c.LocalPeer().ID())
	r := fmt.Sprintf("%s/%s", c.RemoteMultiaddr(), c.RemotePeer().ID())
	lh := u.Hash([]byte(l))
	rh := u.Hash([]byte(r))
	ch := u.XOR(lh, rh)
	return u.Key(ch).Pretty()
}

// Publish implements Publisher. Accepts a keypair and a value,
// and publishes it out to the routing system
func (p *ipnsPublisher) Publish(k ci.PrivKey, value string) error {
	log.Debugf("namesys: Publish %s", value)

	// validate `value` is a ref (multihash)
	_, err := mh.FromB58String(value)
	if err != nil {
		log.Errorf("hash cast failed: %s", value)
		return fmt.Errorf("publish value must be str multihash. %v", err)
	}

	ctx := context.TODO()
	data, err := createRoutingEntryData(k, value)
	if err != nil {
		log.Error("entry creation failed.")
		return err
	}
	pubkey := k.GetPublic()
	pkbytes, err := pubkey.Bytes()
	if err != nil {
		log.Error("pubkey getbytes failed.")
		return err
	}

	nameb := u.Hash(pkbytes)
	namekey := u.Key("/pk/" + string(nameb))

	log.Debugf("Storing pubkey at: %s", namekey)
	// Store associated public key
	timectx, _ := context.WithDeadline(ctx, time.Now().Add(time.Second*4))
	err = p.routing.PutValue(timectx, namekey, pkbytes)
	if err != nil {
		return err
	}

	ipnskey := u.Key("/ipns/" + string(nameb))

	log.Debugf("Storing ipns entry at: %s", ipnskey)
	// Store ipns entry at "/ipns/"+b58(h(pubkey))
	timectx, _ = context.WithDeadline(ctx, time.Now().Add(time.Second*4))
	err = p.routing.PutValue(timectx, ipnskey, data)
	if err != nil {
		return err
	}

	return nil
}

func TestBlockReturnsErr(t *testing.T) {
	off := NewOfflineExchange()
	_, err := off.Block(context.Background(), u.Key("foo"))
	if err != nil {
		return // as desired
	}
	t.Fail()
}

// nearestPeersToQuery returns the routing tables closest peers.
func (dht *IpfsDHT) nearestPeersToQuery(pmes *pb.Message, count int) []peer.Peer {
	level := pmes.GetClusterLevel()
	cluster := dht.routingTables[level]

	key := u.Key(pmes.GetKey())
	closer := cluster.NearestPeers(kb.ConvertKey(key), count)
	return closer
}

func TestAppendWanted(t *testing.T) {
	const str = "foo"
	m := New()
	m.AddWanted(u.Key(str))

	if !contains(m.ToProto().GetWantlist(), str) {
		t.Fail()
	}
}

func TestCopyProtoByValue(t *testing.T) {
	const str = "foo"
	m := New()
	protoBeforeAppend := m.ToProto()
	m.AddWanted(u.Key(str))
	if contains(protoBeforeAppend.GetWantlist(), str) {
		t.Fail()
	}
}

func TestGetWhenKeyNotPresent(t *testing.T) {
	bs := NewBlockstore(ds_sync.MutexWrap(ds.NewMapDatastore()))
	_, err := bs.Get(u.Key("not present"))

	if err != nil {
		t.Log("As expected, block is not present")
		return
	}
	t.Fail()
}