// IDB58Decode returns a b58-decoded Peer
func IDB58Decode(s string) (ID, error) {
	m, err := mh.FromB58String(s)
	if err != nil {
		return "", err
	}
	return ID(m), err
}

// resolveOnce implements resolver. Uses the IPFS routing system to
// resolve SFS-like names.
func (r *routingResolver) resolveOnce(ctx context.Context, name string) (path.Path, error) {
	log.Debugf("RoutingResolve: '%s'", name)
	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 := key.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
	pubkey, err := routing.GetPublicKey(r.routing, ctx, hash)
	if err != nil {
		return "", err
	}

	hsh, _ := pubkey.Hash()
	log.Debugf("pk hash = %s", key.Key(hsh))

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

	// ok sig checks out. this is a valid name.

	// check for old style record:
	valh, err := mh.Cast(entry.GetValue())
	if err != nil {
		// Not a multihash, probably a new record
		return path.ParsePath(string(entry.GetValue()))
	} else {
		// Its an old style multihash record
		log.Warning("Detected old style multihash record")
		return path.FromKey(key.Key(valh)), nil
	}
}

// converts the Node object into a real dag.Node
func deserializeNode(node *Node) (*dag.Node, error) {
	dagnode := new(dag.Node)
	dagnode.Data = []byte(node.Data)
	dagnode.Links = make([]*dag.Link, len(node.Links))
	for i, link := range node.Links {
		hash, err := mh.FromB58String(link.Hash)
		if err != nil {
			return nil, err
		}
		dagnode.Links[i] = &dag.Link{
			Name: link.Name,
			Size: link.Size,
			Hash: hash,
		}
	}

	return dagnode, nil
}

func addressStringToBytes(p Protocol, s string) ([]byte, error) {
	switch p.Code {

	case P_IP4: // ipv4
		i := net.ParseIP(s).To4()
		if i == nil {
			return nil, fmt.Errorf("failed to parse ip4 addr: %s", s)
		}
		return i, nil

	case P_IP6: // ipv6
		i := net.ParseIP(s).To16()
		if i == nil {
			return nil, fmt.Errorf("failed to parse ip6 addr: %s", s)
		}
		return i, nil

	// tcp udp dccp sctp
	case P_TCP, P_UDP, P_DCCP, P_SCTP:
		i, err := strconv.Atoi(s)
		if err != nil {
			return nil, fmt.Errorf("failed to parse %s addr: %s", p.Name, err)
		}
		if i >= 65536 {
			return nil, fmt.Errorf("failed to parse %s addr: %s", p.Name, "greater than 65536")
		}
		b := make([]byte, 2)
		binary.BigEndian.PutUint16(b, uint16(i))
		return b, nil

	case P_IPFS: // ipfs
		// the address is a varint prefixed multihash string representation
		m, err := mh.FromB58String(s)
		if err != nil {
			return nil, fmt.Errorf("failed to parse ipfs addr: %s %s", s, err)
		}
		size := CodeToVarint(len(m))
		b := append(size, m...)
		return b, nil
	}

	return []byte{}, fmt.Errorf("failed to parse %s addr: unknown", p.Name)
}

// SplitAbsPath clean up and split fpath. It extracts the first component (which
// must be a Multihash) and return it separately.
func SplitAbsPath(fpath Path) (mh.Multihash, []string, error) {

	log.Debugf("Resolve: '%s'", fpath)

	parts := fpath.Segments()
	if parts[0] == "ipfs" {
		parts = parts[1:]
	}

	// if nothing, bail.
	if len(parts) == 0 {
		return nil, nil, ErrNoComponents
	}

	// 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, nil, err
	}

	return h, parts[1:], nil
}

func getBlockForKey(req cmds.Request, skey string) (*blocks.Block, error) {
	n, err := req.InvocContext().GetNode()
	if err != nil {
		return nil, err
	}

	if !u.IsValidHash(skey) {
		return nil, errors.New("Not a valid hash")
	}

	h, err := mh.FromB58String(skey)
	if err != nil {
		return nil, err
	}

	k := key.Key(h)
	b, err := n.Blocks.GetBlock(req.Context(), k)
	if err != nil {
		return nil, err
	}

	log.Debugf("ipfs block: got block with key: %q", b.Key())
	return b, nil
}