// NewDHT creates a new DHT object with the given peer as the 'local' host
func NewDHT(ctx context.Context, h host.Host, dstore ds.Datastore) *IpfsDHT {
	dht := new(IpfsDHT)
	dht.datastore = dstore
	dht.self = h.ID()
	dht.peerstore = h.Peerstore()
	dht.host = h

	// register for network notifs.
	dht.host.Network().Notify((*netNotifiee)(dht))

	dht.proc = goprocess.WithTeardown(func() error {
		// remove ourselves from network notifs.
		dht.host.Network().StopNotify((*netNotifiee)(dht))
		return nil
	})

	dht.ctx = ctx

	h.SetStreamHandler(ProtocolDHT, dht.handleNewStream)
	dht.providers = NewProviderManager(dht.ctx, dht.self)
	dht.proc.AddChild(dht.providers.proc)
	goprocessctx.CloseAfterContext(dht.proc, ctx)

	dht.routingTable = kb.NewRoutingTable(20, kb.ConvertPeerID(dht.self), time.Minute, dht.peerstore)
	dht.birth = time.Now()

	dht.Validator = make(record.Validator)
	dht.Validator["pk"] = record.PublicKeyValidator

	dht.Selector = make(record.Selector)
	dht.Selector["pk"] = record.PublicKeySelector

	return dht
}

// NewDHT creates a new DHT object with the given peer as the 'local' host
func NewDHT(ctx context.Context, h host.Host, dstore ds.ThreadSafeDatastore) *IpfsDHT {
	dht := new(IpfsDHT)
	dht.datastore = dstore
	dht.self = h.ID()
	dht.peerstore = h.Peerstore()
	dht.host = h

	// register for network notifs.
	dht.host.Network().Notify((*netNotifiee)(dht))

	dht.ContextGroup = ctxgroup.WithContextAndTeardown(ctx, func() error {
		// remove ourselves from network notifs.
		dht.host.Network().StopNotify((*netNotifiee)(dht))
		return nil
	})

	h.SetStreamHandler(ProtocolDHT, dht.handleNewStream)
	dht.providers = NewProviderManager(dht.Context(), dht.self)
	dht.AddChild(dht.providers)

	dht.routingTable = kb.NewRoutingTable(20, kb.ConvertPeerID(dht.self), time.Minute, dht.peerstore)
	dht.birth = time.Now()

	dht.Validator = make(record.Validator)
	dht.Validator["pk"] = record.PublicKeyValidator

	if doPinging {
		dht.Children().Add(1)
		go dht.PingRoutine(time.Second * 10)
	}
	return dht
}

// FindPeersConnectedToPeer searches for peers directly connected to a given peer.
func (dht *IpfsDHT) FindPeersConnectedToPeer(ctx context.Context, id peer.ID) (<-chan peer.PeerInfo, error) {

	peerchan := make(chan peer.PeerInfo, asyncQueryBuffer)
	peersSeen := peer.Set{}

	peers := dht.routingTable.NearestPeers(kb.ConvertPeerID(id), AlphaValue)
	if len(peers) == 0 {
		return nil, kb.ErrLookupFailure
	}

	// setup the Query
	query := dht.newQuery(key.Key(id), func(ctx context.Context, p peer.ID) (*dhtQueryResult, error) {

		pmes, err := dht.findPeerSingle(ctx, p, id)
		if err != nil {
			return nil, err
		}

		var clpeers []peer.PeerInfo
		closer := pmes.GetCloserPeers()
		for _, pbp := range closer {
			pi := pb.PBPeerToPeerInfo(pbp)

			// skip peers already seen
			if _, found := peersSeen[pi.ID]; found {
				continue
			}
			peersSeen[pi.ID] = struct{}{}

			// if peer is connected, send it to our client.
			if pb.Connectedness(*pbp.Connection) == inet.Connected {
				select {
				case <-ctx.Done():
					return nil, ctx.Err()
				case peerchan <- pi:
				}
			}

			// if peer is the peer we're looking for, don't bother querying it.
			// TODO maybe query it?
			if pb.Connectedness(*pbp.Connection) != inet.Connected {
				clpeers = append(clpeers, pi)
			}
		}

		return &dhtQueryResult{closerPeers: clpeers}, nil
	})

	// run it! run it asynchronously to gen peers as results are found.
	// this does no error checking
	go func() {
		if _, err := query.Run(ctx, peers); err != nil {
			log.Debug(err)
		}

		// close the peerchan channel when done.
		close(peerchan)
	}()

	return peerchan, nil
}

// FindPeer searches for a peer with given ID.
func (dht *IpfsDHT) FindPeer(ctx context.Context, id peer.ID) (peer.PeerInfo, error) {
	defer log.EventBegin(ctx, "FindPeer", id).Done()

	// Check if were already connected to them
	if pi := dht.FindLocal(id); pi.ID != "" {
		return pi, nil
	}

	peers := dht.routingTable.NearestPeers(kb.ConvertPeerID(id), AlphaValue)
	if len(peers) == 0 {
		return peer.PeerInfo{}, kb.ErrLookupFailure
	}

	// Sanity...
	for _, p := range peers {
		if p == id {
			log.Debug("Found target peer in list of closest peers...")
			return dht.peerstore.PeerInfo(p), nil
		}
	}

	// setup the Query
	parent := ctx
	query := dht.newQuery(key.Key(id), func(ctx context.Context, p peer.ID) (*dhtQueryResult, error) {
		notif.PublishQueryEvent(parent, &notif.QueryEvent{
			Type: notif.SendingQuery,
			ID:   p,
		})

		pmes, err := dht.findPeerSingle(ctx, p, id)
		if err != nil {
			return nil, err
		}

		closer := pmes.GetCloserPeers()
		clpeerInfos := pb.PBPeersToPeerInfos(closer)

		// see it we got the peer here
		for _, npi := range clpeerInfos {
			if npi.ID == id {
				return &dhtQueryResult{
					peer:    npi,
					success: true,
				}, nil
			}
		}

		notif.PublishQueryEvent(parent, &notif.QueryEvent{
			Type:      notif.PeerResponse,
			Responses: pointerizePeerInfos(clpeerInfos),
		})

		return &dhtQueryResult{closerPeers: clpeerInfos}, nil
	})

	// run it!
	result, err := query.Run(ctx, peers)
	if err != nil {
		return peer.PeerInfo{}, err
	}

	log.Debugf("FindPeer %v %v", id, result.success)
	if result.peer.ID == "" {
		return peer.PeerInfo{}, routing.ErrNotFound
	}

	return result.peer, nil
}