// 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
}
// ValidateIpnsRecord implements ValidatorFunc and verifies that the
// given 'val' is an IpnsEntry and that that entry is valid.
func ValidateIpnsRecord(k u.Key, val []byte) error {
	entry := new(pb.IpnsEntry)
	err := proto.Unmarshal(val, entry)
	if err != nil {
		return err
	}
	switch entry.GetValidityType() {
	case pb.IpnsEntry_EOL:
		t, err := u.ParseRFC3339(string(entry.GetValue()))
		if err != nil {
			log.Error("Failed parsing time for ipns record EOL")
			return err
		}
		if time.Now().After(t) {
			return ErrExpiredRecord
		}
	default:
		return ErrUnrecognizedValidity
	}
	return nil
}