// LoadPinner loads a pinner and its keysets from the given datastore
func LoadPinner(d ds.Datastore, dserv mdag.DAGService) (Pinner, error) {
	p := new(pinner)

	rootKeyI, err := d.Get(pinDatastoreKey)
	if err != nil {
		return nil, fmt.Errorf("cannot load pin state: %v", err)
	}
	rootKeyBytes, ok := rootKeyI.([]byte)
	if !ok {
		return nil, fmt.Errorf("cannot load pin state: %s was not bytes", pinDatastoreKey)
	}

	rootKey := key.Key(rootKeyBytes)

	ctx, cancel := context.WithTimeout(context.TODO(), time.Second*5)
	defer cancel()

	root, err := dserv.Get(ctx, rootKey)
	if err != nil {
		return nil, fmt.Errorf("cannot find pinning root object: %v", err)
	}

	internalPin := map[key.Key]struct{}{
		rootKey: struct{}{},
	}
	recordInternal := func(k key.Key) {
		internalPin[k] = struct{}{}
	}

	{ // load recursive set
		recurseKeys, err := loadSet(ctx, dserv, root, linkRecursive, recordInternal)
		if err != nil {
			return nil, fmt.Errorf("cannot load recursive pins: %v", err)
		}
		p.recursePin = set.SimpleSetFromKeys(recurseKeys)
	}

	{ // load direct set
		directKeys, err := loadSet(ctx, dserv, root, linkDirect, recordInternal)
		if err != nil {
			return nil, fmt.Errorf("cannot load direct pins: %v", err)
		}
		p.directPin = set.SimpleSetFromKeys(directKeys)
	}

	p.internalPin = internalPin

	// assign services
	p.dserv = dserv
	p.dstore = d

	return p, nil
}

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 getRoutingProviders(ds datastore.Datastore, k key.Key) ([]*dhtpb.Message_Peer, error) {
	e := log.EventBegin(context.Background(), "getProviders", &k)
	defer e.Done()
	var providers []*dhtpb.Message_Peer
	if v, err := ds.Get(providerKey(k)); err == nil {
		if data, ok := v.([]byte); ok {
			var msg dhtpb.Message
			if err := proto.Unmarshal(data, &msg); err != nil {
				return nil, err
			}
			providers = append(providers, msg.GetProviderPeers()...)
		}
	}
	return providers, 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
}

func putRoutingProviders(ds datastore.Datastore, k key.Key, newRecords []*dhtpb.Message_Peer) error {
	log.Event(context.Background(), "putRoutingProviders", &k)
	oldRecords, err := getRoutingProviders(ds, k)
	if err != nil {
		return err
	}
	mergedRecords := make(map[string]*dhtpb.Message_Peer)
	for _, provider := range oldRecords {
		mergedRecords[provider.GetId()] = provider // add original records
	}
	for _, provider := range newRecords {
		mergedRecords[provider.GetId()] = provider // overwrite old record if new exists
	}
	var protomsg dhtpb.Message
	protomsg.ProviderPeers = make([]*dhtpb.Message_Peer, 0, len(mergedRecords))
	for _, provider := range mergedRecords {
		protomsg.ProviderPeers = append(protomsg.ProviderPeers, provider)
	}
	data, err := proto.Marshal(&protomsg)
	if err != nil {
		return err
	}
	return ds.Put(providerKey(k), data)
}