// InvertKey returns a b58 decoded Datastore key
// TODO: this is hacky because it encodes every path component. some
// path components may be proper strings already...
func (b58KeyConverter) InvertKey(dsk ds.Key) ds.Key {
	k := ds.NewKey("/")
	for _, n := range dsk.Namespaces() {
		k = k.ChildString(string(b58.Decode(n)))
	}
	return k
}

// IsValidHash checks whether a given hash is valid (b58 decodable, len > 0)
func IsValidHash(s string) bool {
	out := b58.Decode(s)
	if out == nil || len(out) == 0 {
		return false
	}
	_, err := mh.Cast(out)
	if err != nil {
		return false
	}
	return true
}

func ParseKeyToPath(txt string) (Path, error) {
	chk := b58.Decode(txt)
	if len(chk) == 0 {
		return "", errors.New("not a key")
	}

	_, err := mh.Cast(chk)
	if err != nil {
		return "", err
	}
	return FromKey(key.Key(chk)), nil
}

func FromB58String(s string) (m Multihash, err error) {
	// panic handler, in case we try accessing bytes incorrectly.
	defer func() {
		if e := recover(); e != nil {
			m = Multihash{}
			err = e.(error)
		}
	}()

	//b58 smells like it can panic...
	b := b58.Decode(s)
	return Cast(b)
}

// UnmarshalJSON returns a JSON-encoded Key (string)
func (k *Key) UnmarshalJSON(mk []byte) error {
	var s string
	err := json.Unmarshal(mk, &s)
	if err != nil {
		return err
	}

	*k = Key(string(b58.Decode(s)))
	if len(*k) == 0 && len(s) > 2 { // if b58.Decode fails, k == ""
		return fmt.Errorf("Key.UnmarshalJSON: invalid b58 string: %v", mk)
	}
	return nil
}

func Decode(encoding, digest string) (mh.Multihash, error) {
	switch encoding {
	case "raw":
		return mh.Cast([]byte(digest))
	case "hex":
		return hex.DecodeString(digest)
	case "base58":
		return base58.Decode(digest), nil
	case "base64":
		return base64.StdEncoding.DecodeString(digest)
	default:
		return nil, fmt.Errorf("unknown encoding: %s", encoding)
	}
}

func ParseKeyToPath(txt string) (Path, error) {
	if txt == "" {
		return "", ErrNoComponents
	}

	chk := b58.Decode(txt)
	if len(chk) == 0 {
		return "", errors.New("not a key")
	}

	if _, err := mh.Cast(chk); err != nil {
		return "", err
	}
	return FromKey(key.Key(chk)), nil
}

func (n *IpfsNode) loadID() error {
	if n.Identity != "" {
		return errors.New("identity already loaded")
	}

	cid := n.Repo.Config().Identity.PeerID
	if cid == "" {
		return errors.New("Identity was not set in config (was ipfs init run?)")
	}
	if len(cid) == 0 {
		return errors.New("No peer ID in config! (was ipfs init run?)")
	}

	n.Identity = peer.ID(b58.Decode(cid))
	return nil
}

	Arguments: []cmds.Argument{
		cmds.StringArg("peerid", false, false, "peer.ID of node to look up").EnableStdin(),
	},
	Options: []cmds.Option{
		cmds.StringOption("format", "f", "optional output format"),
	},
	Run: func(req cmds.Request, res cmds.Response) {
		node, err := req.InvocContext().GetNode()
		if err != nil {
			res.SetError(err, cmds.ErrNormal)
			return
		}

		var id peer.ID
		if len(req.Arguments()) > 0 {
			id = peer.ID(b58.Decode(req.Arguments()[0]))
			if len(id) == 0 {
				res.SetError(cmds.ClientError("Invalid peer id"), cmds.ErrClient)
				return
			}
		} else {
			id = node.Identity
		}

		if id == node.Identity {
			output, err := printSelf(node)
			if err != nil {
				res.SetError(err, cmds.ErrNormal)
				return
			}
			res.SetOutput(output)

			return
		}

		if len(req.Arguments()) == 0 {
			output, err := printSelf(node)
			if err != nil {
				res.SetError(err, cmds.ErrNormal)
				return
			}
			res.SetOutput(output)
			return
		}

		pid := req.Arguments()[0]

		id := peer.ID(b58.Decode(pid))
		if len(id) == 0 {
			res.SetError(cmds.ClientError("Invalid peer id"), cmds.ErrClient)
			return
		}

		// TODO handle offline mode with polymorphism instead of conditionals
		if !node.OnlineMode() {
			res.SetError(errors.New(offlineIdErrorMessage), cmds.ErrClient)
			return
		}

		p, err := node.Routing.FindPeer(req.Context().Context, id)
		if err == kb.ErrLookupFailure {
			res.SetError(errors.New(offlineIdErrorMessage), cmds.ErrClient)
			return

// B58KeyDecode returns Key from a b58 encoded string
func B58KeyDecode(s string) Key {
	return Key(string(b58.Decode(s)))
}