// Copyright (C) 2019-2020 Zilliz. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
// or implied. See the License for the specific language governing permissions and limitations under the License.

package querynode

import (
	"context"
	"encoding/binary"
	"errors"
	"math"
	"math/rand"
	"path"
	"strconv"

	"github.com/golang/protobuf/proto"
	"go.uber.org/zap"

	"github.com/milvus-io/milvus/internal/indexnode"
	etcdkv "github.com/milvus-io/milvus/internal/kv/etcd"
	minioKV "github.com/milvus-io/milvus/internal/kv/minio"
	"github.com/milvus-io/milvus/internal/log"
	"github.com/milvus-io/milvus/internal/msgstream"
	"github.com/milvus-io/milvus/internal/proto/commonpb"
	"github.com/milvus-io/milvus/internal/proto/datapb"
	"github.com/milvus-io/milvus/internal/proto/etcdpb"
	"github.com/milvus-io/milvus/internal/proto/internalpb"
	"github.com/milvus-io/milvus/internal/proto/milvuspb"
	"github.com/milvus-io/milvus/internal/proto/planpb"
	"github.com/milvus-io/milvus/internal/proto/schemapb"
	"github.com/milvus-io/milvus/internal/storage"
)

// ---------- unittest util functions ----------
// common definitions
const ctxTimeInMillisecond = 500
const debug = false

const (
	dimKey        = "dim"
	metricTypeKey = "metric_type"

	defaultVecFieldName   = "vec"
	defaultConstFieldName = "const"
	defaultTopK           = int64(10)
	defaultDim            = 128
	defaultNProb          = 10
	defaultMetricType     = "JACCARD"

	defaultKVRootPath = "query-node-unittest"
	defaultVChannel   = "query-node-unittest-channel-0"
	//defaultQueryChannel       = "query-node-unittest-query-channel-0"
	//defaultQueryResultChannel = "query-node-unittest-query-result-channel-0"
	defaultSubName = "query-node-unittest-sub-name-0"
)

const (
	defaultCollectionID = UniqueID(0)
	defaultPartitionID  = UniqueID(1)
	defaultSegmentID    = UniqueID(2)

	defaultCollectionName = "query-node-unittest-default-collection"
	defaultPartitionName  = "query-node-unittest-default-partition"
)

const defaultMsgLength = 100

const (
	buildID   = UniqueID(0)
	indexID   = UniqueID(0)
	indexName = "query-node-index-0"
)

// ---------- unittest util functions ----------
// functions of init meta and generate meta
type vecFieldParam struct {
	id         int64
	dim        int
	metricType string
	vecType    schemapb.DataType
}

type constFieldParam struct {
	id       int64
	dataType schemapb.DataType
}

var simpleVecField = vecFieldParam{
	id:         100,
	dim:        defaultDim,
	metricType: defaultMetricType,
	vecType:    schemapb.DataType_FloatVector,
}

var simpleConstField = constFieldParam{
	id:       101,
	dataType: schemapb.DataType_Int32,
}

var uidField = constFieldParam{
	id:       rowIDFieldID,
	dataType: schemapb.DataType_Int64,
}

var timestampField = constFieldParam{
	id:       timestampFieldID,
	dataType: schemapb.DataType_Int64,
}

func genConstantField(param constFieldParam) *schemapb.FieldSchema {
	field := &schemapb.FieldSchema{
		FieldID:      param.id,
		Name:         defaultConstFieldName,
		IsPrimaryKey: false,
		DataType:     param.dataType,
	}
	return field
}

func genFloatVectorField(param vecFieldParam) *schemapb.FieldSchema {
	fieldVec := &schemapb.FieldSchema{
		FieldID:      param.id,
		Name:         defaultVecFieldName,
		IsPrimaryKey: false,
		DataType:     param.vecType,
		TypeParams: []*commonpb.KeyValuePair{
			{
				Key:   dimKey,
				Value: strconv.Itoa(param.dim),
			},
		},
		IndexParams: []*commonpb.KeyValuePair{
			{
				Key:   metricTypeKey,
				Value: param.metricType,
			},
		},
	}
	return fieldVec
}

func genSimpleIndexParams() indexParam {
	indexParams := make(map[string]string)
	indexParams["index_type"] = "IVF_PQ"
	indexParams["index_mode"] = "cpu"
	indexParams["dim"] = strconv.FormatInt(defaultDim, 10)
	indexParams["k"] = "10"
	indexParams["nlist"] = "100"
	indexParams["nprobe"] = "10"
	indexParams["m"] = "4"
	indexParams["nbits"] = "8"
	indexParams["metric_type"] = "L2"
	indexParams["SLICE_SIZE"] = "400"
	return indexParams
}

func genIndexBinarySet() ([][]byte, error) {
	indexParams := genSimpleIndexParams()

	typeParams := make(map[string]string)
	typeParams["dim"] = strconv.Itoa(defaultDim)
	var indexRowData []float32
	for n := 0; n < defaultMsgLength; n++ {
		for i := 0; i < defaultDim; i++ {
			indexRowData = append(indexRowData, float32(n*i))
		}
	}

	index, err := indexnode.NewCIndex(typeParams, indexParams)
	if err != nil {
		return nil, err
	}

	err = index.BuildFloatVecIndexWithoutIds(indexRowData)
	if err != nil {
		return nil, err
	}

	// save index to minio
	binarySet, err := index.Serialize()
	if err != nil {
		return nil, err
	}

	bytesSet := make([][]byte, 0)
	for i := range binarySet {
		bytesSet = append(bytesSet, binarySet[i].Value)
	}
	return bytesSet, nil
}

func generateIndex(segmentID UniqueID) ([]string, error) {
	indexParams := genSimpleIndexParams()

	var indexParamsKV []*commonpb.KeyValuePair
	for key, value := range indexParams {
		indexParamsKV = append(indexParamsKV, &commonpb.KeyValuePair{
			Key:   key,
			Value: value,
		})
	}

	typeParams := make(map[string]string)
	typeParams["dim"] = strconv.Itoa(defaultDim)
	var indexRowData []float32
	for n := 0; n < defaultMsgLength; n++ {
		for i := 0; i < defaultDim; i++ {
			indexRowData = append(indexRowData, float32(n*i))
		}
	}

	index, err := indexnode.NewCIndex(typeParams, indexParams)
	if err != nil {
		return nil, err
	}

	err = index.BuildFloatVecIndexWithoutIds(indexRowData)
	if err != nil {
		return nil, err
	}

	option := &minioKV.Option{
		Address:           Params.MinioEndPoint,
		AccessKeyID:       Params.MinioAccessKeyID,
		SecretAccessKeyID: Params.MinioSecretAccessKey,
		UseSSL:            Params.MinioUseSSLStr,
		BucketName:        Params.MinioBucketName,
		CreateBucket:      true,
	}

	kv, err := minioKV.NewMinIOKV(context.Background(), option)
	if err != nil {
		return nil, err
	}

	// save index to minio
	binarySet, err := index.Serialize()
	if err != nil {
		return nil, err
	}

	// serialize index params
	var indexCodec storage.IndexCodec
	serializedIndexBlobs, err := indexCodec.Serialize(binarySet, indexParams, indexName, indexID)
	if err != nil {
		return nil, err
	}

	indexPaths := make([]string, 0)
	for _, index := range serializedIndexBlobs {
		p := strconv.Itoa(int(segmentID)) + "/" + index.Key
		indexPaths = append(indexPaths, p)
		err := kv.Save(p, string(index.Value))
		if err != nil {
			return nil, err
		}
	}

	return indexPaths, nil
}

func genSimpleSegCoreSchema() *schemapb.CollectionSchema {
	fieldVec := genFloatVectorField(simpleVecField)
	fieldInt := genConstantField(simpleConstField)

	schema := schemapb.CollectionSchema{ // schema for segCore
		Name:   defaultCollectionName,
		AutoID: true,
		Fields: []*schemapb.FieldSchema{
			fieldVec,
			fieldInt,
		},
	}
	return &schema
}

func genSimpleInsertDataSchema() *schemapb.CollectionSchema {
	fieldUID := genConstantField(uidField)
	fieldTimestamp := genConstantField(timestampField)
	fieldVec := genFloatVectorField(simpleVecField)
	fieldInt := genConstantField(simpleConstField)

	schema := schemapb.CollectionSchema{ // schema for insertData
		Name:   defaultCollectionName,
		AutoID: true,
		Fields: []*schemapb.FieldSchema{
			fieldUID,
			fieldTimestamp,
			fieldVec,
			fieldInt,
		},
	}
	return &schema
}

func genCollectionMeta(collectionID UniqueID, schema *schemapb.CollectionSchema) *etcdpb.CollectionMeta {
	colInfo := &etcdpb.CollectionMeta{
		ID:           collectionID,
		Schema:       schema,
		PartitionIDs: []UniqueID{defaultPartitionID},
	}
	return colInfo
}

func genSimpleCollectionMeta() *etcdpb.CollectionMeta {
	simpleSchema := genSimpleInsertDataSchema()
	return genCollectionMeta(defaultCollectionID, simpleSchema)
}

// ---------- unittest util functions ----------
// functions of third-party
func genMinioKV(ctx context.Context) (*minioKV.MinIOKV, error) {
	bucketName := Params.MinioBucketName
	option := &minioKV.Option{
		Address:           Params.MinioEndPoint,
		AccessKeyID:       Params.MinioAccessKeyID,
		SecretAccessKeyID: Params.MinioSecretAccessKey,
		UseSSL:            Params.MinioUseSSLStr,
		BucketName:        bucketName,
		CreateBucket:      true,
	}
	kv, err := minioKV.NewMinIOKV(ctx, option)
	return kv, err
}

func genEtcdKV() (*etcdkv.EtcdKV, error) {
	etcdKV, err := etcdkv.NewEtcdKV(Params.EtcdEndpoints, Params.MetaRootPath)
	return etcdKV, err
}

func genFactory() (msgstream.Factory, error) {
	const receiveBufSize = 1024

	pulsarURL := Params.PulsarAddress
	msFactory := msgstream.NewPmsFactory()
	m := map[string]interface{}{
		"receiveBufSize": receiveBufSize,
		"pulsarAddress":  pulsarURL,
		"pulsarBufSize":  1024}
	err := msFactory.SetParams(m)
	if err != nil {
		return nil, err
	}
	return msFactory, nil
}

func genQueryMsgStream(ctx context.Context) (msgstream.MsgStream, error) {
	fac, err := genFactory()
	if err != nil {
		return nil, err
	}
	stream, err := fac.NewQueryMsgStream(ctx)
	if err != nil {
		return nil, err
	}
	return stream, nil
}

func genLocalChunkManager() (storage.ChunkManager, error) {
	p, err := Params.Load("storage.path")
	if err != nil {
		return nil, err
	}
	lcm := storage.NewLocalChunkManager(p)

	return lcm, nil
}

func genRemoteChunkManager(ctx context.Context) (storage.ChunkManager, error) {
	client, err := genMinioKV(ctx)
	if err != nil {
		return nil, err
	}
	rcm := storage.NewMinioChunkManager(client)

	return rcm, nil
}

func genVectorChunkManager(ctx context.Context) (storage.ChunkManager, error) {
	p, err := Params.Load("storage.path")
	if err != nil {
		return nil, err
	}
	lcm := storage.NewLocalChunkManager(p)

	client, err := genMinioKV(ctx)
	if err != nil {
		return nil, err
	}
	rcm := storage.NewMinioChunkManager(client)

	schema := genSimpleInsertDataSchema()
	vcm := storage.NewVectorChunkManager(lcm, rcm, &etcdpb.CollectionMeta{
		ID:     defaultCollectionID,
		Schema: schema,
	}, false)
	return vcm, nil
}

// ---------- unittest util functions ----------
// functions of inserting data init
func genInsertData(msgLength int, schema *schemapb.CollectionSchema) (*storage.InsertData, error) {
	insertData := &storage.InsertData{
		Data: make(map[int64]storage.FieldData),
	}

	for _, f := range schema.Fields {
		switch f.DataType {
		case schemapb.DataType_Bool:
			data := make([]bool, msgLength)
			for i := 0; i < msgLength; i++ {
				data[i] = true
			}
			insertData.Data[f.FieldID] = &storage.BoolFieldData{
				NumRows: []int64{int64(msgLength)},
				Data:    data,
			}
		case schemapb.DataType_Int8:
			data := make([]int8, msgLength)
			for i := 0; i < msgLength; i++ {
				data[i] = int8(i)
			}
			insertData.Data[f.FieldID] = &storage.Int8FieldData{
				NumRows: []int64{int64(msgLength)},
				Data:    data,
			}
		case schemapb.DataType_Int16:
			data := make([]int16, msgLength)
			for i := 0; i < msgLength; i++ {
				data[i] = int16(i)
			}
			insertData.Data[f.FieldID] = &storage.Int16FieldData{
				NumRows: []int64{int64(msgLength)},
				Data:    data,
			}
		case schemapb.DataType_Int32:
			data := make([]int32, msgLength)
			for i := 0; i < msgLength; i++ {
				data[i] = int32(i)
			}
			insertData.Data[f.FieldID] = &storage.Int32FieldData{
				NumRows: []int64{int64(msgLength)},
				Data:    data,
			}
		case schemapb.DataType_Int64:
			data := make([]int64, msgLength)
			for i := 0; i < msgLength; i++ {
				data[i] = int64(i)
			}
			insertData.Data[f.FieldID] = &storage.Int64FieldData{
				NumRows: []int64{int64(msgLength)},
				Data:    data,
			}
		case schemapb.DataType_Float:
			data := make([]float32, msgLength)
			for i := 0; i < msgLength; i++ {
				data[i] = float32(i)
			}
			insertData.Data[f.FieldID] = &storage.FloatFieldData{
				NumRows: []int64{int64(msgLength)},
				Data:    data,
			}
		case schemapb.DataType_Double:
			data := make([]float64, msgLength)
			for i := 0; i < msgLength; i++ {
				data[i] = float64(i)
			}
			insertData.Data[f.FieldID] = &storage.DoubleFieldData{
				NumRows: []int64{int64(msgLength)},
				Data:    data,
			}
		case schemapb.DataType_FloatVector:
			dim := simpleVecField.dim // if no dim specified, use simpleVecField's dim
			for _, p := range f.TypeParams {
				if p.Key == dimKey {
					var err error
					dim, err = strconv.Atoi(p.Value)
					if err != nil {
						return nil, err
					}
				}
			}
			data := make([]float32, 0)
			for i := 0; i < msgLength; i++ {
				for j := 0; j < dim; j++ {
					data = append(data, float32(i*j)*0.1)
				}
			}
			insertData.Data[f.FieldID] = &storage.FloatVectorFieldData{
				NumRows: []int64{int64(msgLength)},
				Data:    data,
				Dim:     dim,
			}
		default:
			err := errors.New("data type not supported")
			return nil, err
		}
	}

	return insertData, nil
}

func genSimpleInsertData() (*storage.InsertData, error) {
	schema := genSimpleInsertDataSchema()
	return genInsertData(defaultMsgLength, schema)
}

func genKey(collectionID, partitionID, segmentID UniqueID, fieldID int64) string {
	ids := []string{
		defaultKVRootPath,
		strconv.FormatInt(collectionID, 10),
		strconv.FormatInt(partitionID, 10),
		strconv.FormatInt(segmentID, 10),
		strconv.FormatInt(fieldID, 10),
	}
	return path.Join(ids...)
}

func genStorageBlob(collectionID UniqueID,
	partitionID UniqueID,
	segmentID UniqueID,
	msgLength int,
	schema *schemapb.CollectionSchema) ([]*storage.Blob, error) {
	collMeta := genCollectionMeta(collectionID, schema)
	inCodec := storage.NewInsertCodec(collMeta)
	insertData, err := genInsertData(msgLength, schema)
	if err != nil {
		return nil, err
	}
	// timestamp field not allowed 0 timestamp
	if _, ok := insertData.Data[timestampFieldID]; ok {
		insertData.Data[timestampFieldID].(*storage.Int64FieldData).Data[0] = 1
	}
	binLogs, _, err := inCodec.Serialize(partitionID, segmentID, insertData)

	return binLogs, err
}

func genSimpleStorageBlob() ([]*storage.Blob, error) {
	schema := genSimpleInsertDataSchema()
	return genStorageBlob(defaultCollectionID, defaultPartitionID, defaultSegmentID, defaultMsgLength, schema)
}

func genSimpleFloatVectors() []float32 {
	vec := make([]float32, defaultDim)
	for i := 0; i < defaultDim; i++ {
		vec[i] = rand.Float32()
	}
	return vec
}

func genCommonBlob(msgLength int, schema *schemapb.CollectionSchema) ([]*commonpb.Blob, error) {
	genRawData := func(i int) ([]byte, error) {
		var rawData []byte
		for _, f := range schema.Fields {
			switch f.DataType {
			case schemapb.DataType_Int32:
				bs := make([]byte, 4)
				binary.LittleEndian.PutUint32(bs, uint32(i))
				rawData = append(rawData, bs...)
			case schemapb.DataType_FloatVector:
				dim := simpleVecField.dim // if no dim specified, use simpleVecField's dim
				for _, p := range f.TypeParams {
					if p.Key == dimKey {
						var err error
						dim, err = strconv.Atoi(p.Value)
						if err != nil {
							return nil, err
						}
					}
				}
				for j := 0; j < dim; j++ {
					f := float32(i*j) * 0.1
					buf := make([]byte, 4)
					binary.LittleEndian.PutUint32(buf, math.Float32bits(f))
					rawData = append(rawData, buf...)
				}
			default:
				err := errors.New("data type not supported")
				return nil, err
			}
		}
		return rawData, nil
	}

	var records []*commonpb.Blob
	for i := 0; i < msgLength; i++ {
		data, err := genRawData(i)
		if err != nil {
			return nil, err
		}
		blob := &commonpb.Blob{
			Value: data,
		}
		records = append(records, blob)
	}

	return records, nil
}

func genSimpleCommonBlob() ([]*commonpb.Blob, error) {
	schema := genSimpleSegCoreSchema()
	return genCommonBlob(defaultMsgLength, schema)
}

func saveBinLog(ctx context.Context,
	collectionID UniqueID,
	partitionID UniqueID,
	segmentID UniqueID,
	msgLength int,
	schema *schemapb.CollectionSchema) ([]*datapb.FieldBinlog, error) {
	binLogs, err := genStorageBlob(collectionID,
		partitionID,
		segmentID,
		msgLength,
		schema)
	if err != nil {
		return nil, err
	}

	log.Debug(".. [query node unittest] Saving bin logs to MinIO ..", zap.Int("number", len(binLogs)))
	kvs := make(map[string]string, len(binLogs))

	// write insert binlog
	fieldBinlog := make([]*datapb.FieldBinlog, 0)
	for _, blob := range binLogs {
		fieldID, err := strconv.ParseInt(blob.GetKey(), 10, 64)
		log.Debug("[query node unittest] save binlog", zap.Int64("fieldID", fieldID))
		if err != nil {
			return nil, err
		}

		key := genKey(collectionID, partitionID, segmentID, fieldID)
		kvs[key] = string(blob.Value[:])
		fieldBinlog = append(fieldBinlog, &datapb.FieldBinlog{
			FieldID: fieldID,
			Binlogs: []string{key},
		})
	}
	log.Debug("[query node unittest] save binlog file to MinIO/S3")

	kv, err := genMinioKV(ctx)
	if err != nil {
		return nil, err
	}
	err = kv.MultiSave(kvs)
	return fieldBinlog, err
}

func saveSimpleBinLog(ctx context.Context) ([]*datapb.FieldBinlog, error) {
	schema := genSimpleInsertDataSchema()
	return saveBinLog(ctx, defaultCollectionID, defaultPartitionID, defaultSegmentID, defaultMsgLength, schema)
}

func genSimpleTimestampFieldData() []Timestamp {
	times := make([]Timestamp, defaultMsgLength)
	for i := 0; i < defaultMsgLength; i++ {
		times[i] = Timestamp(i)
	}
	// timestamp 0 is not allowed
	times[0] = 1
	return times
}

func genSimpleRowIDField() []IntPrimaryKey {
	ids := make([]IntPrimaryKey, defaultMsgLength)
	for i := 0; i < defaultMsgLength; i++ {
		ids[i] = IntPrimaryKey(i)
	}
	return ids
}

func genMsgStreamBaseMsg() msgstream.BaseMsg {
	return msgstream.BaseMsg{
		HashValues: []uint32{0},
	}
}

func genCommonMsgBase(msgType commonpb.MsgType) *commonpb.MsgBase {
	return &commonpb.MsgBase{
		MsgType: msgType,
		MsgID:   rand.Int63(),
	}
}

func genSimpleInsertMsg() (*msgstream.InsertMsg, error) {
	rowData, err := genSimpleCommonBlob()
	if err != nil {
		return nil, err
	}

	return &msgstream.InsertMsg{
		BaseMsg: genMsgStreamBaseMsg(),
		InsertRequest: internalpb.InsertRequest{
			Base:           genCommonMsgBase(commonpb.MsgType_Retrieve),
			CollectionName: defaultCollectionName,
			PartitionName:  defaultPartitionName,
			CollectionID:   defaultCollectionID,
			PartitionID:    defaultPartitionID,
			SegmentID:      defaultSegmentID,
			ChannelID:      defaultVChannel,
			Timestamps:     genSimpleTimestampFieldData(),
			RowIDs:         genSimpleRowIDField(),
			RowData:        rowData,
		},
	}, nil
}

// ---------- unittest util functions ----------
// functions of replica
func genSealedSegment(schemaForCreate *schemapb.CollectionSchema,
	schemaForLoad *schemapb.CollectionSchema,
	collectionID,
	partitionID,
	segmentID UniqueID,
	vChannel Channel,
	msgLength int) (*Segment, error) {
	col := newCollection(collectionID, schemaForCreate)
	seg := newSegment(col,
		segmentID,
		partitionID,
		collectionID,
		vChannel,
		segmentTypeSealed,
		true)
	insertData, err := genInsertData(msgLength, schemaForLoad)
	if err != nil {
		return nil, err
	}
	for k, v := range insertData.Data {
		var numRows []int64
		var data interface{}
		switch fieldData := v.(type) {
		case *storage.BoolFieldData:
			numRows = fieldData.NumRows
			data = fieldData.Data
		case *storage.Int8FieldData:
			numRows = fieldData.NumRows
			data = fieldData.Data
		case *storage.Int16FieldData:
			numRows = fieldData.NumRows
			data = fieldData.Data
		case *storage.Int32FieldData:
			numRows = fieldData.NumRows
			data = fieldData.Data
		case *storage.Int64FieldData:
			numRows = fieldData.NumRows
			data = fieldData.Data
		case *storage.FloatFieldData:
			numRows = fieldData.NumRows
			data = fieldData.Data
		case *storage.DoubleFieldData:
			numRows = fieldData.NumRows
			data = fieldData.Data
		case storage.StringFieldData:
			numRows = fieldData.NumRows
			data = fieldData.Data
		case *storage.FloatVectorFieldData:
			numRows = fieldData.NumRows
			data = fieldData.Data
		case *storage.BinaryVectorFieldData:
			numRows = fieldData.NumRows
			data = fieldData.Data
		default:
			return nil, errors.New("unexpected field data type")
		}
		totalNumRows := int64(0)
		for _, numRow := range numRows {
			totalNumRows += numRow
		}
		err := seg.segmentLoadFieldData(k, int(totalNumRows), data)
		if err != nil {
			return nil, err
		}
	}
	return seg, nil
}

func genSimpleSealedSegment() (*Segment, error) {
	schema := genSimpleSegCoreSchema()
	schema2 := genSimpleInsertDataSchema()
	return genSealedSegment(schema,
		schema2,
		defaultCollectionID,
		defaultPartitionID,
		defaultSegmentID,
		defaultVChannel,
		defaultMsgLength)
}

func genSimpleReplica() (ReplicaInterface, error) {
	kv, err := genEtcdKV()
	if err != nil {
		return nil, err
	}
	r := newCollectionReplica(kv)
	schema := genSimpleSegCoreSchema()
	err = r.addCollection(defaultCollectionID, schema)
	if err != nil {
		return nil, err
	}
	err = r.addPartition(defaultCollectionID, defaultPartitionID)
	return r, err
}

func genSimpleHistorical(ctx context.Context) (*historical, error) {
	fac, err := genFactory()
	if err != nil {
		return nil, err
	}
	kv, err := genEtcdKV()
	if err != nil {
		return nil, err
	}
	h := newHistorical(ctx, newMockRootCoord(), newMockIndexCoord(), fac, kv)
	r, err := genSimpleReplica()
	if err != nil {
		return nil, err
	}
	seg, err := genSimpleSealedSegment()
	if err != nil {
		return nil, err
	}
	err = r.setSegment(seg)
	if err != nil {
		return nil, err
	}
	h.replica = r
	h.loader.historicalReplica = r
	col, err := h.replica.getCollectionByID(defaultCollectionID)
	if err != nil {
		return nil, err
	}
	col.addVChannels([]Channel{
		defaultVChannel,
	})
	return h, nil
}

func genSimpleStreaming(ctx context.Context) (*streaming, error) {
	kv, err := genEtcdKV()
	if err != nil {
		return nil, err
	}
	fac, err := genFactory()
	if err != nil {
		return nil, err
	}
	s := newStreaming(ctx, fac, kv)
	r, err := genSimpleReplica()
	if err != nil {
		return nil, err
	}
	err = r.addSegment(defaultSegmentID,
		defaultPartitionID,
		defaultCollectionID,
		defaultVChannel,
		segmentTypeGrowing,
		true)
	if err != nil {
		return nil, err
	}
	s.replica = r
	col, err := s.replica.getCollectionByID(defaultCollectionID)
	if err != nil {
		return nil, err
	}
	col.addVChannels([]Channel{
		defaultVChannel,
	})
	s.tSafeReplica.addTSafe(defaultVChannel)
	return s, nil
}

// ---------- unittest util functions ----------
// functions of messages and requests
func genDSL(schema *schemapb.CollectionSchema, nProb int, topK int64) (string, error) {
	var vecFieldName string
	var metricType string
	nProbStr := strconv.Itoa(nProb)
	topKStr := strconv.FormatInt(topK, 10)
	for _, f := range schema.Fields {
		if f.DataType == schemapb.DataType_FloatVector {
			vecFieldName = f.Name
			for _, p := range f.IndexParams {
				if p.Key == metricTypeKey {
					metricType = p.Value
				}
			}
		}
	}
	if vecFieldName == "" || metricType == "" {
		err := errors.New("invalid vector field name or metric type")
		return "", err
	}

	return "{\"bool\": { " +
		"\"vector\": {" +
		"\"" + vecFieldName + "\": {" +
		" \"metric_type\": \"" + metricType + "\", " +
		" \"params\": {" +
		" \"nprobe\": " + nProbStr + " " +
		"}, \"query\": \"$0\",\"topk\": " + topKStr + " \n } \n } \n } \n }", nil
}

func genSimpleDSL() (string, error) {
	schema := genSimpleSegCoreSchema()
	return genDSL(schema, defaultNProb, defaultTopK)
}

func genSimplePlaceHolderGroup() ([]byte, error) {
	placeholderValue := &milvuspb.PlaceholderValue{
		Tag:    "$0",
		Type:   milvuspb.PlaceholderType_FloatVector,
		Values: make([][]byte, 0),
	}
	for i := 0; i < int(defaultTopK); i++ {
		var vec = make([]float32, defaultDim)
		for j := 0; j < defaultDim; j++ {
			vec[j] = rand.Float32()
		}
		var rawData []byte
		for k, ele := range vec {
			buf := make([]byte, 4)
			binary.LittleEndian.PutUint32(buf, math.Float32bits(ele+float32(k*2)))
			rawData = append(rawData, buf...)
		}
		placeholderValue.Values = append(placeholderValue.Values, rawData)
	}

	// generate placeholder
	placeholderGroup := milvuspb.PlaceholderGroup{
		Placeholders: []*milvuspb.PlaceholderValue{placeholderValue},
	}
	placeGroupByte, err := proto.Marshal(&placeholderGroup)
	if err != nil {
		return nil, err
	}
	return placeGroupByte, nil
}

func genSimpleSearchPlanAndRequests() (*SearchPlan, []*searchRequest, error) {
	schema := genSimpleSegCoreSchema()
	collection := newCollection(defaultCollectionID, schema)

	var plan *SearchPlan
	var err error
	sm, err := genSimpleSearchMsg()
	if err != nil {
		return nil, nil, err
	}
	if sm.GetDslType() == commonpb.DslType_BoolExprV1 {
		expr := sm.SerializedExprPlan
		plan, err = createSearchPlanByExpr(collection, expr)
		if err != nil {
			return nil, nil, err
		}
	} else {
		dsl := sm.Dsl
		plan, err = createSearchPlan(collection, dsl)
		if err != nil {
			return nil, nil, err
		}
	}
	searchRequestBlob := sm.PlaceholderGroup
	searchReq, err := parseSearchRequest(plan, searchRequestBlob)
	if err != nil {
		return nil, nil, err
	}
	searchRequests := make([]*searchRequest, 0)
	searchRequests = append(searchRequests, searchReq)

	return plan, searchRequests, nil
}

func genSimpleRetrievePlanExpr() ([]byte, error) {
	planNode := &planpb.PlanNode{
		Node: &planpb.PlanNode_Predicates{
			Predicates: &planpb.Expr{
				Expr: &planpb.Expr_TermExpr{
					TermExpr: &planpb.TermExpr{
						ColumnInfo: &planpb.ColumnInfo{
							FieldId:  simpleConstField.id,
							DataType: simpleConstField.dataType,
						},
						Values: []*planpb.GenericValue{
							{
								Val: &planpb.GenericValue_Int64Val{
									Int64Val: 1,
								},
							},
							{
								Val: &planpb.GenericValue_Int64Val{
									Int64Val: 2,
								},
							},
							{
								Val: &planpb.GenericValue_Int64Val{
									Int64Val: 3,
								},
							},
						},
					},
				},
			},
		},
		OutputFieldIds: []int64{simpleConstField.id},
	}
	planExpr, err := proto.Marshal(planNode)
	return planExpr, err
}

func genSimpleRetrievePlan() (*RetrievePlan, error) {
	retrieveMsg, err := genSimpleRetrieveMsg()
	if err != nil {
		return nil, err
	}
	timestamp := retrieveMsg.RetrieveRequest.TravelTimestamp

	schema := genSimpleSegCoreSchema()
	collection := newCollection(defaultCollectionID, schema)

	planExpr, err := genSimpleRetrievePlanExpr()
	if err != nil {
		return nil, err
	}

	plan, err := createRetrievePlanByExpr(collection, planExpr, timestamp)
	return plan, err
}

func genSimpleSearchRequest() (*internalpb.SearchRequest, error) {
	placeHolder, err := genSimplePlaceHolderGroup()
	if err != nil {
		return nil, err
	}
	simpleDSL, err := genSimpleDSL()
	if err != nil {
		return nil, err
	}
	return &internalpb.SearchRequest{
		Base:             genCommonMsgBase(commonpb.MsgType_Search),
		CollectionID:     defaultCollectionID,
		PartitionIDs:     []UniqueID{defaultPartitionID},
		Dsl:              simpleDSL,
		PlaceholderGroup: placeHolder,
		DslType:          commonpb.DslType_Dsl,
	}, nil
}

func genSimpleRetrieveRequest() (*internalpb.RetrieveRequest, error) {
	expr, err := genSimpleRetrievePlanExpr()
	if err != nil {
		return nil, err
	}

	return &internalpb.RetrieveRequest{
		Base: &commonpb.MsgBase{
			MsgType: commonpb.MsgType_Retrieve,
			MsgID:   rand.Int63(), // TODO: random msgID?
		},
		CollectionID:       defaultCollectionID,
		PartitionIDs:       []UniqueID{defaultPartitionID},
		OutputFieldsId:     []int64{1, 2, 3},
		TravelTimestamp:    Timestamp(1000),
		SerializedExprPlan: expr,
	}, nil
}

func genSimpleSearchMsg() (*msgstream.SearchMsg, error) {
	req, err := genSimpleSearchRequest()
	if err != nil {
		return nil, err
	}
	return &msgstream.SearchMsg{
		BaseMsg:       genMsgStreamBaseMsg(),
		SearchRequest: *req,
	}, nil
}

func genSimpleRetrieveMsg() (*msgstream.RetrieveMsg, error) {
	req, err := genSimpleRetrieveRequest()
	if err != nil {
		return nil, err
	}
	return &msgstream.RetrieveMsg{
		BaseMsg:         genMsgStreamBaseMsg(),
		RetrieveRequest: *req,
	}, nil
}

func genQueryChannel() Channel {
	const queryChannelPrefix = "query-node-unittest-query-channel-"
	return queryChannelPrefix + strconv.Itoa(rand.Int())
}

func genQueryResultChannel() Channel {
	const queryResultChannelPrefix = "query-node-unittest-query-result-channel-"
	return queryResultChannelPrefix + strconv.Itoa(rand.Int())
}

func produceSimpleSearchMsg(ctx context.Context, queryChannel Channel) error {
	stream, err := genQueryMsgStream(ctx)
	if err != nil {
		return err
	}
	stream.AsProducer([]string{queryChannel})
	stream.Start()
	defer stream.Close()
	msg, err := genSimpleSearchMsg()
	if err != nil {
		return err
	}
	msgPack := &msgstream.MsgPack{
		Msgs: []msgstream.TsMsg{msg},
	}
	err = stream.Produce(msgPack)
	if err != nil {
		return err
	}
	log.Debug("[query node unittest] produce search message done")
	return nil
}

func produceSimpleRetrieveMsg(ctx context.Context, queryChannel Channel) error {
	stream, err := genQueryMsgStream(ctx)
	if err != nil {
		return err
	}
	stream.AsProducer([]string{queryChannel})
	stream.Start()
	defer stream.Close()
	msg, err := genSimpleRetrieveMsg()
	if err != nil {
		return err
	}
	msgPack := &msgstream.MsgPack{
		Msgs: []msgstream.TsMsg{msg},
	}
	err = stream.Produce(msgPack)
	if err != nil {
		return err
	}
	log.Debug("[query node unittest] produce retrieve message done")
	return nil
}

func initConsumer(ctx context.Context, queryResultChannel Channel) (msgstream.MsgStream, error) {
	stream, err := genQueryMsgStream(ctx)
	if err != nil {
		return nil, err
	}
	stream.AsConsumer([]string{queryResultChannel}, defaultSubName)
	stream.Start()
	return stream, nil
}

func consumeSimpleSearchResult(stream msgstream.MsgStream) (*msgstream.SearchResultMsg, error) {
	res := stream.Consume()
	if len(res.Msgs) != 1 {
		err := errors.New("unexpected message length")
		return nil, err
	}
	return res.Msgs[0].(*msgstream.SearchResultMsg), nil
}

func consumeSimpleRetrieveResult(stream msgstream.MsgStream) (*msgstream.RetrieveResultMsg, error) {
	res := stream.Consume()
	if len(res.Msgs) != 1 {
		err := errors.New("unexpected message length")
		return nil, err
	}
	return res.Msgs[0].(*msgstream.RetrieveResultMsg), nil
}

// node
func genSimpleQueryNode(ctx context.Context) (*QueryNode, error) {
	fac, err := genFactory()
	if err != nil {
		return nil, err
	}
	node := NewQueryNode(ctx, fac)

	streaming, err := genSimpleStreaming(ctx)
	if err != nil {
		return nil, err
	}

	historical, err := genSimpleHistorical(ctx)
	if err != nil {
		return nil, err
	}

	node.streaming = streaming
	node.historical = historical

	// start task scheduler
	go node.scheduler.Start()

	qs := newQueryService(ctx, node.historical, node.streaming, node.msFactory)
	defer qs.close()
	node.queryService = qs

	node.UpdateStateCode(internalpb.StateCode_Healthy)

	return node, nil
}