// Stat returns statistics on the node.
func (n *Node) Stat() (*NodeStat, error) {
	enc, err := n.Encoded(false)
	if err != nil {
		return nil, err
	}

	cumSize, err := n.Size()
	if err != nil {
		return nil, err
	}

	key, err := n.Key()
	if err != nil {
		return nil, err
	}

	return &NodeStat{
		Hash:           key.B58String(),
		NumLinks:       len(n.Links),
		BlockSize:      len(enc),
		LinksSize:      len(enc) - len(n.Data), // includes framing.
		DataSize:       len(n.Data),
		CumulativeSize: int(cumSize),
	}, nil
}

func (adder *Adder) addNode(node *dag.Node, path string) error {
	// patch it into the root
	if path == "" {
		key, err := node.Key()
		if err != nil {
			return err
		}

		path = key.B58String()
	}

	dir := gopath.Dir(path)
	if dir != "." {
		if err := mfs.Mkdir(adder.mr, dir, true, false); err != nil {
			return err
		}
	}

	if err := mfs.PutNode(adder.mr, path, node); err != nil {
		return err
	}

	if !adder.Silent {
		return outputDagnode(adder.out, path, node)
	}
	return nil
}

func (dht *IpfsDHT) handleAddProvider(ctx context.Context, p peer.ID, pmes *pb.Message) (*pb.Message, error) {
	lm := make(lgbl.DeferredMap)
	lm["peer"] = func() interface{} { return p.Pretty() }

	defer log.EventBegin(ctx, "handleAddProvider", lm).Done()
	key := key.Key(pmes.GetKey())
	lm["key"] = func() interface{} { return key.B58String() }

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

	// add provider should use the address given in the message
	pinfos := pb.PBPeersToPeerInfos(pmes.GetProviderPeers())
	for _, pi := range pinfos {
		if pi.ID != p {
			// we should ignore this provider reccord! not from originator.
			// (we chould sign them and check signature later...)
			log.Debugf("handleAddProvider received provider %s from %s. Ignore.", pi.ID, p)
			continue
		}

		if len(pi.Addrs) < 1 {
			log.Debugf("%s got no valid addresses for provider %s. Ignore.", dht.self, p)
			continue
		}

		log.Infof("received provider %s for %s (addrs: %s)", p, key, pi.Addrs)
		if pi.ID != dht.self { // dont add own addrs.
			// add the received addresses to our peerstore.
			dht.peerstore.AddAddrs(pi.ID, pi.Addrs, pstore.ProviderAddrTTL)
		}
		dht.providers.AddProvider(ctx, key, p)
	}

	return nil, nil
}

// KeyListTextMarshaler outputs a KeyList as plaintext, one key per line
func KeyListTextMarshaler(res cmds.Response) (io.Reader, error) {
	output := res.Output().(*KeyList)
	buf := new(bytes.Buffer)
	for _, key := range output.Keys {
		buf.WriteString(key.B58String() + "\n")
	}
	return buf, nil
}

func (dht *IpfsDHT) handleGetProviders(ctx context.Context, p peer.ID, pmes *pb.Message) (*pb.Message, error) {
	lm := make(lgbl.DeferredMap)
	lm["peer"] = func() interface{} { return p.Pretty() }
	defer log.EventBegin(ctx, "handleGetProviders", lm).Done()

	resp := pb.NewMessage(pmes.GetType(), pmes.GetKey(), pmes.GetClusterLevel())
	key := key.Key(pmes.GetKey())
	lm["key"] = func() interface{} { return key.B58String() }

	// debug logging niceness.
	reqDesc := fmt.Sprintf("%s handleGetProviders(%s, %s): ", dht.self, p, key)
	log.Debugf("%s begin", reqDesc)
	defer log.Debugf("%s end", reqDesc)

	// check if we have this value, to add ourselves as provider.
	has, err := dht.datastore.Has(key.DsKey())
	if err != nil && err != ds.ErrNotFound {
		log.Debugf("unexpected datastore error: %v\n", err)
		has = false
	}

	// setup providers
	providers := dht.providers.GetProviders(ctx, key)
	if has {
		providers = append(providers, dht.self)
		log.Debugf("%s have the value. added self as provider", reqDesc)
	}

	if providers != nil && len(providers) > 0 {
		infos := pstore.PeerInfos(dht.peerstore, providers)
		resp.ProviderPeers = pb.PeerInfosToPBPeers(dht.host.Network(), infos)
		log.Debugf("%s have %d providers: %s", reqDesc, len(providers), infos)
	}

	// Also send closer peers.
	closer := dht.betterPeersToQuery(pmes, p, CloserPeerCount)
	if closer != nil {
		infos := pstore.PeerInfos(dht.peerstore, closer)
		resp.CloserPeers = pb.PeerInfosToPBPeers(dht.host.Network(), infos)
		log.Debugf("%s have %d closer peers: %s", reqDesc, len(closer), infos)
	}

	return resp, nil
}

// from core/commands/object.go
func getOutput(dagnode *dag.Node) (*Object, error) {
	key, err := dagnode.Key()
	if err != nil {
		return nil, err
	}

	output := &Object{
		Hash:  key.B58String(),
		Links: make([]Link, len(dagnode.Links)),
	}

	for i, link := range dagnode.Links {
		output.Links[i] = Link{
			Name: link.Name,
			//Hash: link.Hash.B58String(),
			Size: link.Size,
		}
	}

	return output, nil
}