// Ensure shards with deprecated "OwnerIDs" can be decoded.
func TestShardInfo_UnmarshalBinary_OwnerIDs(t *testing.T) {
	// Encode deprecated form to bytes.
	buf, err := proto.Marshal(&internal.ShardInfo{
		ID:       proto.Uint64(1),
		OwnerIDs: []uint64{10, 20, 30},
	})
	if err != nil {
		t.Fatal(err)
	}

	// Decode deprecated form.
	var si meta.ShardInfo
	if err := si.UnmarshalBinary(buf); err != nil {
		t.Fatal(err)
	}

	// Verify data is migrated correctly.
	if !reflect.DeepEqual(si, meta.ShardInfo{
		ID: 1,
		Owners: []meta.ShardOwner{
			{NodeID: 10},
			{NodeID: 20},
			{NodeID: 30},
		},
	}) {
		t.Fatalf("unexpected shard info: %s", spew.Sdump(si))
	}
}

// CreateMapper returns a Mapper for the given shard ID.
func (r *ShardMapper) CreateMapper(sh meta.ShardInfo, stmt string, chunkSize int) (tsdb.Mapper, error) {
	var err error
	var m tsdb.Mapper
	if sh.OwnedBy(r.MetaStore.NodeID()) {
		m, err = r.TSDBStore.CreateMapper(sh.ID, stmt, chunkSize)
		if err != nil {
			return nil, err
		}
	} else {
		m = NewRemoteMaper(sh.OwnerIDs[0], sh.ID, stmt, chunkSize)
	}

	return m, nil
}

// CreateMapper returns a Mapper for the given shard ID.
func (s *ShardMapper) CreateMapper(sh meta.ShardInfo, stmt influxql.Statement, chunkSize int) (tsdb.Mapper, error) {
	m, err := s.TSDBStore.CreateMapper(sh.ID, stmt, chunkSize)
	if err != nil {
		return nil, err
	}

	if !sh.OwnedBy(s.MetaStore.NodeID()) || s.ForceRemoteMapping {
		// Pick a node in a pseudo-random manner.
		conn, err := s.dial(sh.OwnerIDs[rand.Intn(len(sh.OwnerIDs))])
		if err != nil {
			return nil, err
		}
		conn.SetDeadline(time.Now().Add(s.timeout))

		m.SetRemote(NewRemoteMapper(conn.(*pool.PoolConn), sh.ID, stmt, chunkSize))
	}

	return m, nil
}

// CreateMapper returns a Mapper for the given shard ID.
func (s *ShardMapper) CreateMapper(sh meta.ShardInfo, stmt influxql.Statement, chunkSize int) (tsdb.Mapper, error) {
	// Create a remote mapper if the local node doesn't own the shard.
	if !sh.OwnedBy(s.MetaStore.NodeID()) || s.ForceRemoteMapping {
		// Pick a node in a pseudo-random manner.
		conn, err := s.dial(sh.Owners[rand.Intn(len(sh.Owners))].NodeID)
		if err != nil {
			return nil, err
		}
		conn.SetDeadline(time.Now().Add(s.timeout))

		return NewRemoteMapper(conn, sh.ID, stmt, chunkSize), nil
	}

	// If it is local then return the mapper from the store.
	m, err := s.TSDBStore.CreateMapper(sh.ID, stmt, chunkSize)
	if err != nil {
		return nil, err
	}

	return m, nil
}

// CreateMapper returns a Mapper for the given shard ID.
func (s *ShardMapper) CreateMapper(sh meta.ShardInfo, stmt string, chunkSize int) (tsdb.Mapper, error) {
	var err error
	var m tsdb.Mapper
	if sh.OwnedBy(s.MetaStore.NodeID()) && !s.ForceRemoteMapping {
		m, err = s.TSDBStore.CreateMapper(sh.ID, stmt, chunkSize)
		if err != nil {
			return nil, err
		}
	} else {
		// Pick a node in a pseudo-random manner.
		conn, err := s.dial(sh.OwnerIDs[rand.Intn(len(sh.OwnerIDs))])
		if err != nil {
			return nil, err
		}
		conn.SetDeadline(time.Now().Add(s.timeout))

		rm := NewRemoteMapper(conn.(*pool.PoolConn), sh.ID, stmt, chunkSize)
		m = rm
	}

	return m, nil
}