// Get retrieves a node from the dagService, fetching the block in the BlockService
func (n *dagService) Get(ctx context.Context, k key.Key) (*Node, error) {
	if k == "" {
		return nil, ErrNotFound
	}
	if n == nil {
		return nil, fmt.Errorf("dagService is nil")
	}
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	b, err := n.Blocks.GetBlock(ctx, k)
	if err != nil {
		if err == bserv.ErrNotFound {
			return nil, ErrNotFound
		}
		return nil, fmt.Errorf("Failed to get block for %s: %v", k.B58String(), err)
	}

	res, err := DecodeProtobuf(b.Data())
	if err != nil {
		if strings.Contains(err.Error(), "Unmarshal failed") {
			return nil, fmt.Errorf("The block referred to by '%s' was not a valid merkledag node", k)
		}
		return nil, fmt.Errorf("Failed to decode Protocol Buffers: %v", err)
	}

	res.cached = k.ToMultihash()

	return res, nil
}

func (bs *blockstore) Get(k key.Key) (blocks.Block, error) {
	if k == "" {
		return nil, ErrNotFound
	}

	maybeData, err := bs.datastore.Get(k.DsKey())
	if err == ds.ErrNotFound {
		return nil, ErrNotFound
	}
	if err != nil {
		return nil, err
	}
	bdata, ok := maybeData.([]byte)
	if !ok {
		return nil, ValueTypeMismatch
	}

	if bs.rehash {
		rb := blocks.NewBlock(bdata)
		if rb.Key() != k {
			return nil, ErrHashMismatch
		} else {
			return rb, nil
		}
	} else {
		return blocks.NewBlockWithHash(bdata, mh.Multihash(k))
	}
}

// Write one edge
func (rw *RefWriter) WriteEdge(from, to key.Key, linkname string) error {
	if rw.Ctx != nil {
		select {
		case <-rw.Ctx.Done(): // just in case.
			return rw.Ctx.Err()
		default:
		}
	}

	var s string
	switch {
	case rw.PrintFmt != "":
		s = rw.PrintFmt
		s = strings.Replace(s, "<src>", from.Pretty(), -1)
		s = strings.Replace(s, "<dst>", to.Pretty(), -1)
		s = strings.Replace(s, "<linkname>", linkname, -1)
	case rw.PrintEdge:
		s = from.Pretty() + " -> " + to.Pretty()
	default:
		s += to.Pretty()
	}

	rw.out <- &RefWrapper{Ref: s}
	return nil
}

func (d *datastoreBlockSet) AddBlock(k key.Key) {
	err := d.dstore.Put(k.DsKey(), []byte{})
	if err != nil {
		log.Debugf("blockset put error: %s", err)
	}

	d.bset.AddBlock(k)
}

func putRoutingRecord(ds datastore.Datastore, k key.Key, value *dhtpb.Record) error {
	data, err := proto.Marshal(value)
	if err != nil {
		return err
	}
	dskey := k.DsKey()
	// TODO namespace
	if err := ds.Put(dskey, data); err != nil {
		return err
	}
	return nil
}

func (bs *blockstore) Get(k key.Key) (*blocks.Block, error) {
	maybeData, err := bs.datastore.Get(k.DsKey())
	if err == ds.ErrNotFound {
		return nil, ErrNotFound
	}
	if err != nil {
		return nil, err
	}
	bdata, ok := maybeData.([]byte)
	if !ok {
		return nil, ValueTypeMismatch
	}

	return blocks.NewBlockWithHash(bdata, mh.Multihash(k))
}

// getLocal attempts to retrieve the value from the datastore
func (dht *IpfsDHT) getLocal(key key.Key) (*pb.Record, error) {

	log.Debug("getLocal %s", key)
	v, err := dht.datastore.Get(key.DsKey())
	if err != nil {
		return nil, err
	}
	log.Debug("found in db")

	byt, ok := v.([]byte)
	if !ok {
		return nil, errors.New("value stored in datastore not []byte")
	}
	rec := new(pb.Record)
	err = proto.Unmarshal(byt, rec)
	if err != nil {
		return nil, err
	}

	err = dht.verifyRecordLocally(rec)
	if err != nil {
		log.Debugf("local record verify failed: %s (discarded)", err)
		return nil, err
	}

	return rec, nil
}

func getRoutingRecord(ds datastore.Datastore, k key.Key) (*dhtpb.Record, error) {
	dskey := k.DsKey()
	val, err := ds.Get(dskey)
	if err != nil {
		return nil, err
	}
	recordBytes, ok := val.([]byte)
	if !ok {
		return nil, fmt.Errorf("datastore had non byte-slice value for %v", dskey)
	}
	var record dhtpb.Record
	if err := proto.Unmarshal(recordBytes, &record); err != nil {
		return nil, errors.New("failed to unmarshal dht record from datastore")
	}
	return &record, nil
}

// putLocal stores the key value pair in the datastore
func (dht *IpfsDHT) putLocal(key key.Key, rec *pb.Record) error {
	data, err := proto.Marshal(rec)
	if err != nil {
		return err
	}

	return dht.datastore.Put(key.DsKey(), data)
}

func (p *ipnsPublisher) getPreviousSeqNo(ctx context.Context, ipnskey key.Key) (uint64, error) {
	prevrec, err := p.ds.Get(ipnskey.DsKey())
	if err != nil && err != ds.ErrNotFound {
		// None found, lets start at zero!
		return 0, err
	}
	var val []byte
	if err == nil {
		prbytes, ok := prevrec.([]byte)
		if !ok {
			return 0, fmt.Errorf("unexpected type returned from datastore: %#v", prevrec)
		}
		dhtrec := new(dhtpb.Record)
		err := proto.Unmarshal(prbytes, dhtrec)
		if err != nil {
			return 0, err
		}

		val = dhtrec.GetValue()
	} else {
		// try and check the dht for a record
		ctx, cancel := context.WithTimeout(ctx, time.Second*30)
		defer cancel()

		rv, err := p.routing.GetValue(ctx, ipnskey)
		if err != nil {
			// no such record found, start at zero!
			return 0, nil
		}

		val = rv
	}

	e := new(pb.IpnsEntry)
	err = proto.Unmarshal(val, e)
	if err != nil {
		return 0, err
	}

	return e.GetSequence(), nil
}

// Get retrieves a node from the dagService, fetching the block in the BlockService
func (n *dagService) Get(ctx context.Context, k key.Key) (*Node, error) {
	if n == nil {
		return nil, fmt.Errorf("dagService is nil")
	}
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	b, err := n.Blocks.GetBlock(ctx, k)
	if err != nil {
		if err == bserv.ErrNotFound {
			return nil, ErrNotFound
		}
		return nil, fmt.Errorf("Failed to get block for %s: %v", k.B58String(), err)
	}

	res, err := DecodeProtobuf(b.Data)
	if err != nil {
		return nil, fmt.Errorf("Failed to decode Protocol Buffers: %v", err)
	}
	return res, nil
}

func (rp *Republisher) getLastVal(k key.Key) (path.Path, uint64, error) {
	ival, err := rp.ds.Get(k.DsKey())
	if err != nil {
		// not found means we dont have a previously published entry
		return "", 0, errNoEntry
	}

	val := ival.([]byte)
	dhtrec := new(dhtpb.Record)
	err = proto.Unmarshal(val, dhtrec)
	if err != nil {
		return "", 0, err
	}

	// extract published data from record
	e := new(pb.IpnsEntry)
	err = proto.Unmarshal(dhtrec.GetValue(), e)
	if err != nil {
		return "", 0, err
	}
	return path.Path(e.Value), e.GetSequence(), nil
}

// FIXME(brian): is this method meant to simulate putting a value into the network?
func (c *client) PutValue(ctx context.Context, key key.Key, val []byte) error {
	log.Debugf("PutValue: %s", key)
	rec := new(dhtpb.Record)
	rec.Value = val
	rec.Key = proto.String(string(key))
	rec.TimeReceived = proto.String(u.FormatRFC3339(time.Now()))
	data, err := proto.Marshal(rec)
	if err != nil {
		return err
	}

	return c.datastore.Put(key.DsKey(), data)
}

// FIXME(brian): is this method meant to simulate getting a value from the network?
func (c *client) GetValue(ctx context.Context, key key.Key) ([]byte, error) {
	log.Debugf("GetValue: %s", key)
	v, err := c.datastore.Get(key.DsKey())
	if err != nil {
		return nil, err
	}

	data, ok := v.([]byte)
	if !ok {
		return nil, errors.New("could not cast value from datastore")
	}

	return data, nil
}

// FIXME(brian): is this method meant to simulate getting a value from the network?
func (c *client) GetValue(ctx context.Context, key key.Key) ([]byte, error) {
	log.Debugf("GetValue: %s", key)
	v, err := c.datastore.Get(key.DsKey())
	if err != nil {
		return nil, err
	}

	data, ok := v.([]byte)
	if !ok {
		return nil, errors.New("could not cast value from datastore")
	}

	rec := new(dhtpb.Record)
	err = proto.Unmarshal(data, rec)
	if err != nil {
		return nil, err
	}

	return rec.GetValue(), nil
}

func (s *blockstore) DeleteBlock(k key.Key) error {
	return s.datastore.Delete(k.DsKey())
}

// FIXME(brian): is this method meant to simulate putting a value into the network?
func (c *client) PutValue(ctx context.Context, key key.Key, val []byte) error {
	log.Debugf("PutValue: %s", key)
	return c.datastore.Put(key.DsKey(), val)
}

func providerKey(k key.Key) datastore.Key {
	return datastore.KeyWithNamespaces([]string{"routing", "providers", k.String()})
}

func (d *datastoreBlockSet) RemoveBlock(k key.Key) {
	d.bset.RemoveBlock(k)
	if !d.bset.HasKey(k) {
		d.dstore.Delete(k.DsKey())
	}
}

func (bs *blockstore) Has(k key.Key) (bool, error) {
	return bs.datastore.Has(k.DsKey())
}