package storage

import (
	"bytes"
	"context"
	"strconv"
	"time"

	"github.com/apache/arrow/go/v17/arrow"
	"github.com/apache/arrow/go/v17/arrow/array"
	"github.com/apache/arrow/go/v17/arrow/memory"
	"github.com/apache/arrow/go/v17/parquet"
	"github.com/apache/arrow/go/v17/parquet/file"
	"github.com/apache/arrow/go/v17/parquet/pqarrow"
	"google.golang.org/protobuf/proto"

	"github.com/milvus-io/milvus-proto/go-api/v3/schemapb"
	"github.com/milvus-io/milvus/pkg/v3/mlog"
	"github.com/milvus-io/milvus/pkg/v3/util/merr"
	"github.com/milvus-io/milvus/pkg/v3/util/typeutil"
)

// PayloadReader reads data from payload
type PayloadReader struct {
	reader   *file.Reader
	colType  schemapb.DataType
	numRows  int64
	nullable bool
	// For VectorArray type
	elementType schemapb.DataType
	// For VectorArray type
	dim int64
}

var _ PayloadReaderInterface = (*PayloadReader)(nil)

func NewPayloadReader(colType schemapb.DataType, buf []byte, nullable bool) (*PayloadReader, error) {
	if len(buf) == 0 {
		return nil, merr.WrapErrDataIntegrityMsg("create Payload reader failed, buffer is empty")
	}
	parquetReader, err := file.NewParquetReader(bytes.NewReader(buf))
	if err != nil {
		return nil, err
	}

	reader := &PayloadReader{
		reader:   parquetReader,
		colType:  colType,
		numRows:  parquetReader.NumRows(),
		nullable: nullable,
	}

	if colType == schemapb.DataType_ArrayOfVector {
		arrowReader, err := pqarrow.NewFileReader(parquetReader, pqarrow.ArrowReadProperties{BatchSize: 1024}, memory.DefaultAllocator)
		if err != nil {
			return nil, merr.WrapErrStorage(err, "failed to create arrow reader for VectorArray")
		}

		arrowSchema, err := arrowReader.Schema()
		if err != nil {
			return nil, merr.WrapErrStorage(err, "failed to get arrow schema for VectorArray")
		}

		if arrowSchema.NumFields() != 1 {
			return nil, merr.WrapErrDataIntegrityMsg("VectorArray should have exactly 1 field, got %d", arrowSchema.NumFields())
		}

		field := arrowSchema.Field(0)
		if !field.HasMetadata() {
			return nil, merr.WrapErrDataIntegrityMsg("VectorArray field is missing metadata")
		}

		metadata := field.Metadata

		elementTypeStr, ok := metadata.GetValue("elementType")
		if !ok {
			return nil, merr.WrapErrDataIntegrityMsg("VectorArray metadata missing required 'elementType' field")
		}
		elementTypeInt, err := strconv.ParseInt(elementTypeStr, 10, 32)
		if err != nil {
			return nil, merr.WrapErrDataIntegrityMsg("invalid elementType in VectorArray metadata: %s", elementTypeStr)
		}

		elementType := schemapb.DataType(elementTypeInt)
		switch elementType {
		case schemapb.DataType_FloatVector,
			schemapb.DataType_BinaryVector,
			schemapb.DataType_Float16Vector,
			schemapb.DataType_BFloat16Vector,
			schemapb.DataType_Int8Vector,
			schemapb.DataType_SparseFloatVector:
			reader.elementType = elementType
		default:
			return nil, merr.WrapErrDataIntegrityMsg("invalid vector type for VectorArray: %s", elementType.String())
		}

		dimStr, ok := metadata.GetValue("dim")
		if !ok {
			return nil, merr.WrapErrDataIntegrityMsg("VectorArray metadata missing required 'dim' field")
		}
		dimVal, err := strconv.ParseInt(dimStr, 10, 64)
		if err != nil {
			return nil, merr.WrapErrDataIntegrityMsg("invalid dim in VectorArray metadata: %s", dimStr)
		}
		if dimVal <= 0 {
			return nil, merr.WrapErrDataIntegrityMsg("VectorArray dim must be positive, got %d", dimVal)
		}
		reader.dim = dimVal
	}

	return reader, nil
}

// GetDataFromPayload returns data,length from payload, returns err if failed
// Return:
//

//		`interface{}`: all types.
//	 `[]bool`: validData, only meaningful to ScalarField.
//		`int`: dim, only meaningful to FLOAT/BINARY VECTOR type.
//		`error`: error.
func (r *PayloadReader) GetDataFromPayload() (interface{}, []bool, int, error) {
	switch r.colType {
	case schemapb.DataType_Bool:
		val, validData, err := r.GetBoolFromPayload()
		return val, validData, 0, err
	case schemapb.DataType_Int8:
		val, validData, err := r.GetInt8FromPayload()
		return val, validData, 0, err
	case schemapb.DataType_Int16:
		val, validData, err := r.GetInt16FromPayload()
		return val, validData, 0, err
	case schemapb.DataType_Int32:
		val, validData, err := r.GetInt32FromPayload()
		return val, validData, 0, err
	case schemapb.DataType_Int64:
		val, validData, err := r.GetInt64FromPayload()
		return val, validData, 0, err
	case schemapb.DataType_Float:
		val, validData, err := r.GetFloatFromPayload()
		return val, validData, 0, err
	case schemapb.DataType_Double:
		val, validData, err := r.GetDoubleFromPayload()
		return val, validData, 0, err
	case schemapb.DataType_Timestamptz:
		val, validData, err := r.GetTimestamptzFromPayload()
		return val, validData, 0, err
	case schemapb.DataType_BinaryVector:
		val, dim, validData, _, err := r.GetBinaryVectorFromPayload()
		return val, validData, dim, err
	case schemapb.DataType_FloatVector:
		val, dim, validData, _, err := r.GetFloatVectorFromPayload()
		return val, validData, dim, err
	case schemapb.DataType_Float16Vector:
		val, dim, validData, _, err := r.GetFloat16VectorFromPayload()
		return val, validData, dim, err
	case schemapb.DataType_BFloat16Vector:
		val, dim, validData, _, err := r.GetBFloat16VectorFromPayload()
		return val, validData, dim, err
	case schemapb.DataType_SparseFloatVector:
		val, dim, validData, err := r.GetSparseFloatVectorFromPayload()
		return val, validData, dim, err
	case schemapb.DataType_Int8Vector:
		val, dim, validData, _, err := r.GetInt8VectorFromPayload()
		return val, validData, dim, err
	case schemapb.DataType_String, schemapb.DataType_VarChar:
		val, validData, err := r.GetStringFromPayload()
		return val, validData, 0, err
	case schemapb.DataType_Array:
		val, validData, err := r.GetArrayFromPayload()
		return val, validData, 0, err
	case schemapb.DataType_ArrayOfVector:
		val, err := r.GetVectorArrayFromPayload()
		return val, nil, 0, err
	case schemapb.DataType_JSON:
		val, validData, err := r.GetJSONFromPayload()
		return val, validData, 0, err
	case schemapb.DataType_Geometry:
		val, validData, err := r.GetGeometryFromPayload()
		return val, validData, 0, err
	default:
		return nil, nil, 0, merr.WrapErrDataIntegrityMsg("unknown type")
	}
}

// ReleasePayloadReader release payload reader.
func (r *PayloadReader) ReleasePayloadReader() error {
	return r.Close()
}

// GetBoolFromPayload returns bool slice from payload.
func (r *PayloadReader) GetBoolFromPayload() ([]bool, []bool, error) {
	if r.colType != schemapb.DataType_Bool {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get bool from datatype %v", r.colType.String())
	}

	values := make([]bool, r.numRows)

	if r.nullable {
		validData := make([]bool, r.numRows)
		valuesRead, err := ReadData[bool, *array.Boolean](r.reader, values, validData, r.numRows)
		if err != nil {
			return nil, nil, err
		}
		if valuesRead != r.numRows {
			return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
		}
		return values, validData, nil
	}
	valuesRead, err := ReadDataFromAllRowGroups[bool, *file.BooleanColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, nil, err
	}
	if valuesRead != r.numRows {
		return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
	}
	return values, nil, nil
}

// GetByteFromPayload returns byte slice from payload
func (r *PayloadReader) GetByteFromPayload() ([]byte, []bool, error) {
	if r.colType != schemapb.DataType_Int8 {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get byte from datatype %v", r.colType.String())
	}

	if r.nullable {
		values := make([]int32, r.numRows)
		validData := make([]bool, r.numRows)
		valuesRead, err := ReadData[int32, *array.Int32](r.reader, values, validData, r.numRows)
		if err != nil {
			return nil, nil, err
		}
		if valuesRead != r.numRows {
			return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
		}
		ret := make([]byte, r.numRows)
		for i := int64(0); i < r.numRows; i++ {
			ret[i] = byte(values[i])
		}
		return ret, validData, nil
	}
	values := make([]int32, r.numRows)
	valuesRead, err := ReadDataFromAllRowGroups[int32, *file.Int32ColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, nil, err
	}

	if valuesRead != r.numRows {
		return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
	}

	ret := make([]byte, r.numRows)
	for i := int64(0); i < r.numRows; i++ {
		ret[i] = byte(values[i])
	}
	return ret, nil, nil
}

func (r *PayloadReader) GetInt8FromPayload() ([]int8, []bool, error) {
	if r.colType != schemapb.DataType_Int8 {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get int8 from datatype %v", r.colType.String())
	}

	if r.nullable {
		values := make([]int8, r.numRows)
		validData := make([]bool, r.numRows)
		valuesRead, err := ReadData[int8, *array.Int8](r.reader, values, validData, r.numRows)
		if err != nil {
			return nil, nil, err
		}

		if valuesRead != r.numRows {
			return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
		}

		return values, validData, nil
	}
	values := make([]int32, r.numRows)
	valuesRead, err := ReadDataFromAllRowGroups[int32, *file.Int32ColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, nil, err
	}

	if valuesRead != r.numRows {
		return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
	}

	ret := make([]int8, r.numRows)
	for i := int64(0); i < r.numRows; i++ {
		ret[i] = int8(values[i])
	}
	return ret, nil, nil
}

func (r *PayloadReader) GetInt16FromPayload() ([]int16, []bool, error) {
	if r.colType != schemapb.DataType_Int16 {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get int16 from datatype %v", r.colType.String())
	}

	if r.nullable {
		values := make([]int16, r.numRows)
		validData := make([]bool, r.numRows)
		valuesRead, err := ReadData[int16, *array.Int16](r.reader, values, validData, r.numRows)
		if err != nil {
			return nil, nil, err
		}

		if valuesRead != r.numRows {
			return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
		}
		return values, validData, nil
	}
	values := make([]int32, r.numRows)
	valuesRead, err := ReadDataFromAllRowGroups[int32, *file.Int32ColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, nil, err
	}

	if valuesRead != r.numRows {
		return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
	}

	ret := make([]int16, r.numRows)
	for i := int64(0); i < r.numRows; i++ {
		ret[i] = int16(values[i])
	}
	return ret, nil, nil
}

func (r *PayloadReader) GetInt32FromPayload() ([]int32, []bool, error) {
	if r.colType != schemapb.DataType_Int32 {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get int32 from datatype %v", r.colType.String())
	}

	values := make([]int32, r.numRows)
	if r.nullable {
		validData := make([]bool, r.numRows)
		valuesRead, err := ReadData[int32, *array.Int32](r.reader, values, validData, r.numRows)
		if err != nil {
			return nil, nil, err
		}

		if valuesRead != r.numRows {
			return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
		}
		return values, validData, nil
	}
	valuesRead, err := ReadDataFromAllRowGroups[int32, *file.Int32ColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, nil, err
	}

	if valuesRead != r.numRows {
		return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
	}
	return values, nil, nil
}

func (r *PayloadReader) GetInt64FromPayload() ([]int64, []bool, error) {
	if r.colType != schemapb.DataType_Int64 {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get int64 from datatype %v", r.colType.String())
	}

	values := make([]int64, r.numRows)
	if r.nullable {
		validData := make([]bool, r.numRows)
		valuesRead, err := ReadData[int64, *array.Int64](r.reader, values, validData, r.numRows)
		if err != nil {
			return nil, nil, err
		}

		if valuesRead != r.numRows {
			return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
		}

		return values, validData, nil
	}
	valuesRead, err := ReadDataFromAllRowGroups[int64, *file.Int64ColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, nil, err
	}

	if valuesRead != r.numRows {
		return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
	}

	return values, nil, nil
}

func (r *PayloadReader) GetFloatFromPayload() ([]float32, []bool, error) {
	if r.colType != schemapb.DataType_Float {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get float32 from datatype %v", r.colType.String())
	}

	values := make([]float32, r.numRows)
	if r.nullable {
		validData := make([]bool, r.numRows)
		valuesRead, err := ReadData[float32, *array.Float32](r.reader, values, validData, r.numRows)
		if err != nil {
			return nil, nil, err
		}
		if valuesRead != r.numRows {
			return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
		}
		return values, validData, nil
	}
	valuesRead, err := ReadDataFromAllRowGroups[float32, *file.Float32ColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, nil, err
	}
	if valuesRead != r.numRows {
		return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
	}
	return values, nil, nil
}

func (r *PayloadReader) GetDoubleFromPayload() ([]float64, []bool, error) {
	if r.colType != schemapb.DataType_Double {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get double from datatype %v", r.colType.String())
	}

	values := make([]float64, r.numRows)
	if r.nullable {
		validData := make([]bool, r.numRows)
		valuesRead, err := ReadData[float64, *array.Float64](r.reader, values, validData, r.numRows)
		if err != nil {
			return nil, nil, err
		}

		if valuesRead != r.numRows {
			return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
		}
		return values, validData, nil
	}
	valuesRead, err := ReadDataFromAllRowGroups[float64, *file.Float64ColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, nil, err
	}

	if valuesRead != r.numRows {
		return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
	}
	return values, nil, nil
}

func (r *PayloadReader) GetTimestamptzFromPayload() ([]int64, []bool, error) {
	if r.colType != schemapb.DataType_Timestamptz {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get timestamptz from datatype %v", r.colType.String())
	}

	values := make([]int64, r.numRows)
	if r.nullable {
		validData := make([]bool, r.numRows)
		valuesRead, err := ReadData[int64, *array.Int64](r.reader, values, validData, r.numRows)
		if err != nil {
			return nil, nil, err
		}

		if valuesRead != r.numRows {
			return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
		}

		return values, validData, nil
	}
	valuesRead, err := ReadDataFromAllRowGroups[int64, *file.Int64ColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, nil, err
	}

	if valuesRead != r.numRows {
		return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
	}

	return values, nil, nil
}

func (r *PayloadReader) GetStringFromPayload() ([]string, []bool, error) {
	if r.colType != schemapb.DataType_String && r.colType != schemapb.DataType_VarChar {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get string from datatype %v", r.colType.String())
	}

	if r.nullable {
		values := make([]string, r.numRows)
		validData := make([]bool, r.numRows)
		valuesRead, err := ReadData[string, *array.String](r.reader, values, validData, r.numRows)
		if err != nil {
			return nil, nil, err
		}

		if valuesRead != r.numRows {
			return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
		}
		return values, validData, nil
	}
	value, err := readByteAndConvert(r, func(bytes parquet.ByteArray) string {
		return bytes.String()
	})
	if err != nil {
		return nil, nil, err
	}
	return value, nil, nil
}

func (r *PayloadReader) GetArrayFromPayload() ([]*schemapb.ScalarField, []bool, error) {
	if r.colType != schemapb.DataType_Array {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get array from datatype %v", r.colType.String())
	}

	if r.nullable {
		return readNullableByteAndConvert(r, func(bytes []byte) *schemapb.ScalarField {
			v := &schemapb.ScalarField{}
			proto.Unmarshal(bytes, v)
			return v
		})
	}
	value, err := readByteAndConvert(r, func(bytes parquet.ByteArray) *schemapb.ScalarField {
		v := &schemapb.ScalarField{}
		proto.Unmarshal(bytes, v)
		return v
	})
	if err != nil {
		return nil, nil, err
	}
	return value, nil, nil
}

func (r *PayloadReader) GetVectorArrayFromPayload() ([]*schemapb.VectorField, error) {
	if r.colType != schemapb.DataType_ArrayOfVector {
		return nil, merr.WrapErrDataIntegrityMsg("failed to get vector from datatype %v", r.colType.String())
	}

	return readVectorArrayFromListArray(r)
}

func (r *PayloadReader) GetJSONFromPayload() ([][]byte, []bool, error) {
	if r.colType != schemapb.DataType_JSON {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get json from datatype %v", r.colType.String())
	}

	if r.nullable {
		return readNullableByteAndConvert(r, func(bytes []byte) []byte {
			return bytes
		})
	}
	value, err := readByteAndConvert(r, func(bytes parquet.ByteArray) []byte {
		return bytes
	})
	if err != nil {
		return nil, nil, err
	}
	return value, nil, nil
}

func (r *PayloadReader) GetGeometryFromPayload() ([][]byte, []bool, error) {
	if r.colType != schemapb.DataType_Geometry {
		return nil, nil, merr.WrapErrDataIntegrityMsg("failed to get Geometry from datatype %v", r.colType.String())
	}

	if r.nullable {
		return readNullableByteAndConvert(r, func(bytes []byte) []byte {
			return bytes
		})
	}
	value, err := readByteAndConvert(r, func(bytes parquet.ByteArray) []byte {
		return bytes
	})
	if err != nil {
		return nil, nil, err
	}
	return value, nil, nil
}

func (r *PayloadReader) GetByteArrayDataSet() (*DataSet[parquet.ByteArray, *file.ByteArrayColumnChunkReader], error) {
	if r.colType != schemapb.DataType_String && r.colType != schemapb.DataType_VarChar {
		return nil, merr.WrapErrServiceInternalMsg("failed to get string from datatype %v", r.colType.String())
	}

	return NewDataSet[parquet.ByteArray, *file.ByteArrayColumnChunkReader](r.reader, 0, r.numRows), nil
}

func (r *PayloadReader) GetArrowRecordReader() (pqarrow.RecordReader, error) {
	arrowReader, err := pqarrow.NewFileReader(r.reader, pqarrow.ArrowReadProperties{BatchSize: 1024}, memory.DefaultAllocator)
	if err != nil {
		return nil, err
	}

	rr, err := arrowReader.GetRecordReader(context.Background(), nil, nil)
	if err != nil {
		return nil, err
	}
	return rr, nil
}

// readVectorArrayFromListArray reads VectorArray data stored as Arrow ListArray
func readVectorArrayFromListArray(r *PayloadReader) ([]*schemapb.VectorField, error) {
	arrowReader, err := pqarrow.NewFileReader(r.reader, pqarrow.ArrowReadProperties{BatchSize: 1024}, memory.DefaultAllocator)
	if err != nil {
		return nil, err
	}
	defer arrowReader.ParquetReader().Close()

	// Read all row groups
	table, err := arrowReader.ReadTable(context.Background())
	if err != nil {
		return nil, err
	}
	defer table.Release()

	if table.NumCols() != 1 {
		return nil, merr.WrapErrDataIntegrityMsg("expected 1 column, got %d", table.NumCols())
	}

	column := table.Column(0)
	if column.Len() == 0 {
		return []*schemapb.VectorField{}, nil
	}

	result := make([]*schemapb.VectorField, 0, int(r.numRows))

	elementType := r.elementType
	dim := r.dim
	for _, chunk := range column.Data().Chunks() {
		listArray, ok := chunk.(*array.List)
		if !ok {
			return nil, merr.WrapErrDataIntegrityMsg("expected ListArray, got %T", chunk)
		}

		for i := 0; i < listArray.Len(); i++ {
			value, err := deserializeArrayOfVector(listArray, i, elementType, dim, true)
			if err != nil {
				return nil, merr.Wrapf(err, "failed to deserialize VectorArray at row %d", len(result))
			}
			vectorField, _ := value.(*schemapb.VectorField)
			if vectorField == nil {
				return nil, merr.WrapErrDataIntegrityMsg("null value in VectorArray")
			}
			result = append(result, vectorField)
		}
	}

	return result, nil
}

func readNullableByteAndConvert[T any](r *PayloadReader, convert func([]byte) T) ([]T, []bool, error) {
	values := make([][]byte, r.numRows)
	validData := make([]bool, r.numRows)
	valuesRead, err := ReadData[[]byte, *array.Binary](r.reader, values, validData, r.numRows)
	if err != nil {
		return nil, nil, err
	}

	if valuesRead != r.numRows {
		return nil, nil, merr.WrapErrDataIntegrityMsg("valuesRead is not equal to rows: expected=%d actual=%d", r.numRows, valuesRead)
	}

	ret := make([]T, r.numRows)
	for i := 0; i < int(r.numRows); i++ {
		ret[i] = convert(values[i])
	}
	return ret, validData, nil
}

func readByteAndConvert[T any](r *PayloadReader, convert func(parquet.ByteArray) T) ([]T, error) {
	values := make([]parquet.ByteArray, r.numRows)
	valuesRead, err := ReadDataFromAllRowGroups[parquet.ByteArray, *file.ByteArrayColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, err
	}

	if valuesRead != r.numRows {
		return nil, merr.WrapErrDataIntegrityMsg("expect %d rows, but got valuesRead = %d", r.numRows, valuesRead)
	}

	ret := make([]T, r.numRows)
	for i := 0; i < int(r.numRows); i++ {
		ret[i] = convert(values[i])
	}
	return ret, nil
}

// GetBinaryVectorFromPayload returns vector, dimension, validData, numRows, error
func (r *PayloadReader) GetBinaryVectorFromPayload() ([]byte, int, []bool, int, error) {
	if r.colType != schemapb.DataType_BinaryVector {
		return nil, -1, nil, 0, merr.WrapErrServiceInternalMsg("failed to get binary vector from datatype %v", r.colType.String())
	}

	if r.nullable {
		fileReader, err := pqarrow.NewFileReader(r.reader, pqarrow.ArrowReadProperties{}, memory.DefaultAllocator)
		if err != nil {
			return nil, -1, nil, 0, err
		}

		arrowSchema, err := fileReader.Schema()
		if err != nil {
			return nil, -1, nil, 0, err
		}

		if arrowSchema.NumFields() != 1 {
			return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expected 1 field, got %d", arrowSchema.NumFields())
		}

		field := arrowSchema.Field(0)
		var dim int

		if field.Type.ID() == arrow.BINARY {
			if !field.HasMetadata() {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("nullable binary vector field is missing metadata")
			}
			metadata := field.Metadata
			dimStr, ok := metadata.GetValue("dim")
			if !ok {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("nullable binary vector metadata missing required 'dim' field")
			}
			var err error
			dim, err = strconv.Atoi(dimStr)
			if err != nil {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("invalid dim value in metadata: %v", err)
			}
			dim = dim / 8
		} else {
			col, err := r.reader.RowGroup(0).Column(0)
			if err != nil {
				return nil, -1, nil, 0, err
			}
			dim = col.Descriptor().TypeLength()
		}

		table, err := fileReader.ReadTable(context.Background())
		if err != nil {
			return nil, -1, nil, 0, err
		}
		defer table.Release()

		if table.NumCols() != 1 {
			return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expected 1 column, got %d", table.NumCols())
		}

		column := table.Column(0)
		ret, validData, err := readNullableVectorData(column, r.numRows, dim)
		if err != nil {
			return nil, -1, nil, 0, err
		}

		return ret, dim * 8, validData, int(r.numRows), nil
	}

	col, err := r.reader.RowGroup(0).Column(0)
	if err != nil {
		return nil, -1, nil, 0, err
	}
	dim := col.Descriptor().TypeLength()

	values := make([]parquet.FixedLenByteArray, r.numRows)
	valuesRead, err := ReadDataFromAllRowGroups[parquet.FixedLenByteArray, *file.FixedLenByteArrayColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, -1, nil, 0, err
	}

	if valuesRead != r.numRows {
		return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expect %d rows, but got valuesRead = %d", r.numRows, valuesRead)
	}

	ret := make([]byte, int64(dim)*r.numRows)
	for i := 0; i < int(r.numRows); i++ {
		copy(ret[i*dim:(i+1)*dim], values[i])
	}
	return ret, dim * 8, nil, int(r.numRows), nil
}

// GetFloat16VectorFromPayload returns vector, dimension, validData, numRows, error
func (r *PayloadReader) GetFloat16VectorFromPayload() ([]byte, int, []bool, int, error) {
	if r.colType != schemapb.DataType_Float16Vector {
		return nil, -1, nil, 0, merr.WrapErrServiceInternalMsg("failed to get float16 vector from datatype %v", r.colType.String())
	}
	if r.nullable {
		fileReader, err := pqarrow.NewFileReader(r.reader, pqarrow.ArrowReadProperties{}, memory.DefaultAllocator)
		if err != nil {
			return nil, -1, nil, 0, err
		}

		arrowSchema, err := fileReader.Schema()
		if err != nil {
			return nil, -1, nil, 0, err
		}

		if arrowSchema.NumFields() != 1 {
			return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expected 1 field, got %d", arrowSchema.NumFields())
		}

		field := arrowSchema.Field(0)
		var dim int

		if field.Type.ID() == arrow.BINARY {
			if !field.HasMetadata() {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("nullable float16 vector field is missing metadata")
			}
			metadata := field.Metadata
			dimStr, ok := metadata.GetValue("dim")
			if !ok {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("nullable float16 vector metadata missing required 'dim' field")
			}
			var err error
			dim, err = strconv.Atoi(dimStr)
			if err != nil {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("invalid dim value in metadata: %v", err)
			}
		} else {
			col, err := r.reader.RowGroup(0).Column(0)
			if err != nil {
				return nil, -1, nil, 0, err
			}
			dim = col.Descriptor().TypeLength() / 2
		}

		table, err := fileReader.ReadTable(context.Background())
		if err != nil {
			return nil, -1, nil, 0, err
		}
		defer table.Release()

		if table.NumCols() != 1 {
			return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expected 1 column, got %d", table.NumCols())
		}

		column := table.Column(0)
		ret, validData, err := readNullableVectorData(column, r.numRows, dim*2)
		if err != nil {
			return nil, -1, nil, 0, err
		}

		return ret, dim, validData, int(r.numRows), nil
	}

	col, err := r.reader.RowGroup(0).Column(0)
	if err != nil {
		return nil, -1, nil, 0, err
	}

	dim := col.Descriptor().TypeLength() / 2

	values := make([]parquet.FixedLenByteArray, r.numRows)
	valuesRead, err := ReadDataFromAllRowGroups[parquet.FixedLenByteArray, *file.FixedLenByteArrayColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, -1, nil, 0, err
	}

	if valuesRead != r.numRows {
		return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expect %d rows, but got valuesRead = %d", r.numRows, valuesRead)
	}

	ret := make([]byte, int64(dim*2)*r.numRows)
	for i := 0; i < int(r.numRows); i++ {
		copy(ret[i*dim*2:(i+1)*dim*2], values[i])
	}
	return ret, dim, nil, int(r.numRows), nil
}

// GetBFloat16VectorFromPayload returns vector, dimension, validData, numRows, error
func (r *PayloadReader) GetBFloat16VectorFromPayload() ([]byte, int, []bool, int, error) {
	if r.colType != schemapb.DataType_BFloat16Vector {
		return nil, -1, nil, 0, merr.WrapErrServiceInternalMsg("failed to get bfloat16 vector from datatype %v", r.colType.String())
	}
	if r.nullable {
		fileReader, err := pqarrow.NewFileReader(r.reader, pqarrow.ArrowReadProperties{}, memory.DefaultAllocator)
		if err != nil {
			return nil, -1, nil, 0, err
		}

		arrowSchema, err := fileReader.Schema()
		if err != nil {
			return nil, -1, nil, 0, err
		}

		if arrowSchema.NumFields() != 1 {
			return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expected 1 field, got %d", arrowSchema.NumFields())
		}

		field := arrowSchema.Field(0)
		var dim int

		if field.Type.ID() == arrow.BINARY {
			if !field.HasMetadata() {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("nullable bfloat16 vector field is missing metadata")
			}
			metadata := field.Metadata
			dimStr, ok := metadata.GetValue("dim")
			if !ok {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("nullable bfloat16 vector metadata missing required 'dim' field")
			}
			var err error
			dim, err = strconv.Atoi(dimStr)
			if err != nil {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("invalid dim value in metadata: %v", err)
			}
		} else {
			col, err := r.reader.RowGroup(0).Column(0)
			if err != nil {
				return nil, -1, nil, 0, err
			}
			dim = col.Descriptor().TypeLength() / 2
		}

		table, err := fileReader.ReadTable(context.Background())
		if err != nil {
			return nil, -1, nil, 0, err
		}
		defer table.Release()

		if table.NumCols() != 1 {
			return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expected 1 column, got %d", table.NumCols())
		}

		column := table.Column(0)
		ret, validData, err := readNullableVectorData(column, r.numRows, dim*2)
		if err != nil {
			return nil, -1, nil, 0, err
		}

		return ret, dim, validData, int(r.numRows), nil
	}

	col, err := r.reader.RowGroup(0).Column(0)
	if err != nil {
		return nil, -1, nil, 0, err
	}

	dim := col.Descriptor().TypeLength() / 2

	values := make([]parquet.FixedLenByteArray, r.numRows)
	valuesRead, err := ReadDataFromAllRowGroups[parquet.FixedLenByteArray, *file.FixedLenByteArrayColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, -1, nil, 0, err
	}

	if valuesRead != r.numRows {
		return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expect %d rows, but got valuesRead = %d", r.numRows, valuesRead)
	}

	ret := make([]byte, int64(dim*2)*r.numRows)
	for i := 0; i < int(r.numRows); i++ {
		copy(ret[i*dim*2:(i+1)*dim*2], values[i])
	}
	return ret, dim, nil, int(r.numRows), nil
}

// GetFloatVectorFromPayload returns vector, dimension, validData, numRows, error
func (r *PayloadReader) GetFloatVectorFromPayload() ([]float32, int, []bool, int, error) {
	if r.colType != schemapb.DataType_FloatVector {
		return nil, -1, nil, 0, merr.WrapErrServiceInternalMsg("failed to get float vector from datatype %v", r.colType.String())
	}
	if r.nullable {
		fileReader, err := pqarrow.NewFileReader(r.reader, pqarrow.ArrowReadProperties{}, memory.DefaultAllocator)
		if err != nil {
			return nil, -1, nil, 0, err
		}

		arrowSchema, err := fileReader.Schema()
		if err != nil {
			return nil, -1, nil, 0, err
		}

		if arrowSchema.NumFields() != 1 {
			return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expected 1 field, got %d", arrowSchema.NumFields())
		}

		field := arrowSchema.Field(0)
		var dim int

		if field.Type.ID() == arrow.BINARY {
			if !field.HasMetadata() {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("nullable float vector field is missing metadata")
			}
			metadata := field.Metadata
			dimStr, ok := metadata.GetValue("dim")
			if !ok {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("nullable float vector metadata missing required 'dim' field")
			}
			var err error
			dim, err = strconv.Atoi(dimStr)
			if err != nil {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("invalid dim value in metadata: %v", err)
			}
		} else {
			col, err := r.reader.RowGroup(0).Column(0)
			if err != nil {
				return nil, -1, nil, 0, err
			}
			dim = col.Descriptor().TypeLength() / 4
		}

		table, err := fileReader.ReadTable(context.Background())
		if err != nil {
			return nil, -1, nil, 0, err
		}
		defer table.Release()

		if table.NumCols() != 1 {
			return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expected 1 column, got %d", table.NumCols())
		}

		column := table.Column(0)
		retBytes, validData, err := readNullableVectorData(column, r.numRows, dim*4)
		if err != nil {
			return nil, -1, nil, 0, err
		}

		return arrow.Float32Traits.CastFromBytes(retBytes), dim, validData, int(r.numRows), nil
	}

	col, err := r.reader.RowGroup(0).Column(0)
	if err != nil {
		return nil, -1, nil, 0, err
	}

	dim := col.Descriptor().TypeLength() / 4

	values := make([]parquet.FixedLenByteArray, r.numRows)
	valuesRead, err := ReadDataFromAllRowGroups[parquet.FixedLenByteArray, *file.FixedLenByteArrayColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, -1, nil, 0, err
	}

	if valuesRead != r.numRows {
		return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expect %d rows, but got valuesRead = %d", r.numRows, valuesRead)
	}

	ret := make([]float32, int64(dim)*r.numRows)
	for i := 0; i < int(r.numRows); i++ {
		copy(arrow.Float32Traits.CastToBytes(ret[i*dim:(i+1)*dim]), values[i])
	}
	return ret, dim, nil, int(r.numRows), nil
}

// GetSparseFloatVectorFromPayload returns fieldData, dimension, validData, error
func (r *PayloadReader) GetSparseFloatVectorFromPayload() (*SparseFloatVectorFieldData, int, []bool, error) {
	if !typeutil.IsSparseFloatVectorType(r.colType) {
		return nil, -1, nil, merr.WrapErrServiceInternalMsg("failed to get sparse float vector from datatype %v", r.colType.String())
	}

	if r.nullable {
		fieldData := &SparseFloatVectorFieldData{}
		validData := make([]bool, r.numRows)

		fileReader, err := pqarrow.NewFileReader(r.reader, pqarrow.ArrowReadProperties{}, memory.DefaultAllocator)
		if err != nil {
			return nil, -1, nil, err
		}

		table, err := fileReader.ReadTable(context.Background())
		if err != nil {
			return nil, -1, nil, err
		}
		defer table.Release()

		if table.NumCols() != 1 {
			return nil, -1, nil, merr.WrapErrDataIntegrityMsg("expected 1 column, got %d", table.NumCols())
		}

		column := table.Column(0)
		offset := 0
		for _, chunk := range column.Data().Chunks() {
			binaryArray, ok := chunk.(*array.Binary)
			if !ok {
				return nil, -1, nil, merr.WrapErrDataIntegrityMsg("expected Binary array, got %T", chunk)
			}

			for i := 0; i < binaryArray.Len(); i++ {
				validData[offset+i] = binaryArray.IsValid(i)
				if validData[offset+i] {
					value := binaryArray.Value(i)
					if len(value)%8 != 0 {
						return nil, -1, nil, merr.WrapErrDataIntegrityMsg("invalid bytesData length")
					}
					fieldData.Contents = append(fieldData.Contents, append([]byte{}, value...))
					rowDim := typeutil.SparseFloatRowDim(value)
					if rowDim > fieldData.Dim {
						fieldData.Dim = rowDim
					}
				}
			}
			offset += binaryArray.Len()
		}

		return fieldData, int(fieldData.Dim), validData, nil
	}

	values := make([]parquet.ByteArray, r.numRows)
	valuesRead, err := ReadDataFromAllRowGroups[parquet.ByteArray, *file.ByteArrayColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, -1, nil, err
	}
	if valuesRead != r.numRows {
		return nil, -1, nil, merr.WrapErrDataIntegrityMsg("expect %d binary, but got = %d", r.numRows, valuesRead)
	}

	fieldData := &SparseFloatVectorFieldData{}

	for _, value := range values {
		if len(value)%8 != 0 {
			return nil, -1, nil, merr.WrapErrDataIntegrityMsg("invalid bytesData length")
		}

		fieldData.Contents = append(fieldData.Contents, value)
		rowDim := typeutil.SparseFloatRowDim(value)
		if rowDim > fieldData.Dim {
			fieldData.Dim = rowDim
		}
	}

	return fieldData, int(fieldData.Dim), nil, nil
}

// GetInt8VectorFromPayload returns vector, dimension, validData, numRows, error
func (r *PayloadReader) GetInt8VectorFromPayload() ([]int8, int, []bool, int, error) {
	if r.colType != schemapb.DataType_Int8Vector {
		return nil, -1, nil, 0, merr.WrapErrServiceInternalMsg("failed to get int8 vector from datatype %v", r.colType.String())
	}
	if r.nullable {
		fileReader, err := pqarrow.NewFileReader(r.reader, pqarrow.ArrowReadProperties{}, memory.DefaultAllocator)
		if err != nil {
			return nil, -1, nil, 0, err
		}

		arrowSchema, err := fileReader.Schema()
		if err != nil {
			return nil, -1, nil, 0, err
		}

		if arrowSchema.NumFields() != 1 {
			return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expected 1 field, got %d", arrowSchema.NumFields())
		}

		field := arrowSchema.Field(0)
		var dim int

		if field.Type.ID() == arrow.BINARY {
			if !field.HasMetadata() {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("nullable int8 vector field is missing metadata")
			}
			metadata := field.Metadata
			dimStr, ok := metadata.GetValue("dim")
			if !ok {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("nullable int8 vector metadata missing required 'dim' field")
			}
			var err error
			dim, err = strconv.Atoi(dimStr)
			if err != nil {
				return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("invalid dim value in metadata: %v", err)
			}
		} else {
			col, err := r.reader.RowGroup(0).Column(0)
			if err != nil {
				return nil, -1, nil, 0, err
			}
			dim = col.Descriptor().TypeLength()
		}

		table, err := fileReader.ReadTable(context.Background())
		if err != nil {
			return nil, -1, nil, 0, err
		}
		defer table.Release()

		if table.NumCols() != 1 {
			return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expected 1 column, got %d", table.NumCols())
		}

		column := table.Column(0)
		retBytes, validData, err := readNullableVectorData(column, r.numRows, dim)
		if err != nil {
			return nil, -1, nil, 0, err
		}

		return arrow.Int8Traits.CastFromBytes(retBytes), dim, validData, int(r.numRows), nil
	}

	col, err := r.reader.RowGroup(0).Column(0)
	if err != nil {
		return nil, -1, nil, 0, err
	}

	dim := col.Descriptor().TypeLength()

	values := make([]parquet.FixedLenByteArray, r.numRows)
	valuesRead, err := ReadDataFromAllRowGroups[parquet.FixedLenByteArray, *file.FixedLenByteArrayColumnChunkReader](r.reader, values, 0, r.numRows)
	if err != nil {
		return nil, -1, nil, 0, err
	}

	if valuesRead != r.numRows {
		return nil, -1, nil, 0, merr.WrapErrDataIntegrityMsg("expect %d rows, but got valuesRead = %d", r.numRows, valuesRead)
	}

	ret := make([]int8, int64(dim)*r.numRows)
	for i := 0; i < int(r.numRows); i++ {
		int8Vals := arrow.Int8Traits.CastFromBytes(values[i])
		copy(ret[i*dim:(i+1)*dim], int8Vals)
	}
	return ret, dim, nil, int(r.numRows), nil
}

func (r *PayloadReader) GetPayloadLengthFromReader() (int, error) {
	return int(r.numRows), nil
}

// Close closes the payload reader
func (r *PayloadReader) Close() error {
	return r.reader.Close()
}

// ReadDataFromAllRowGroups iterates all row groups of file.Reader, and convert column to E.
// then calls ReadBatch with provided parameters.
func ReadDataFromAllRowGroups[T any, E interface {
	ReadBatch(int64, []T, []int16, []int16) (int64, int, error)
}](reader *file.Reader, values []T, columnIdx int, numRows int64) (int64, error) {
	var offset int64

	for i := 0; i < reader.NumRowGroups(); i++ {
		if columnIdx >= reader.RowGroup(i).NumColumns() {
			return -1, merr.WrapErrDataIntegrityMsg("try to fetch %d-th column of reader but row group has only %d column(s)", columnIdx, reader.RowGroup(i).NumColumns())
		}
		column, err := reader.RowGroup(i).Column(columnIdx)
		if err != nil {
			return -1, err
		}

		cReader, ok := column.(E)
		if !ok {
			return -1, merr.WrapErrDataIntegrityMsg("expect type %T, but got %T", *new(E), column)
		}

		_, valuesRead, err := cReader.ReadBatch(numRows, values[offset:], nil, nil)
		if err != nil {
			return -1, err
		}

		offset += int64(valuesRead)
	}

	return offset, nil
}

type DataSet[T any, E interface {
	ReadBatch(int64, []T, []int16, []int16) (int64, int, error)
}] struct {
	reader  *file.Reader
	cReader E

	cnt, numRows       int64
	groupID, columnIdx int
}

func NewDataSet[T any, E interface {
	ReadBatch(int64, []T, []int16, []int16) (int64, int, error)
}](reader *file.Reader, columnIdx int, numRows int64) *DataSet[T, E] {
	return &DataSet[T, E]{
		reader:    reader,
		columnIdx: columnIdx,
		numRows:   numRows,
	}
}

func (s *DataSet[T, E]) nextGroup() error {
	s.cnt = 0
	column, err := s.reader.RowGroup(s.groupID).Column(s.columnIdx)
	if err != nil {
		return err
	}

	cReader, ok := column.(E)
	if !ok {
		return merr.WrapErrDataIntegrityMsg("expect type %T, but got %T", *new(E), column)
	}
	s.groupID++
	s.cReader = cReader
	return nil
}

func (s *DataSet[T, E]) HasNext() bool {
	if s.groupID > s.reader.NumRowGroups() || (s.groupID == s.reader.NumRowGroups() && s.cnt >= s.numRows) || s.numRows == 0 {
		return false
	}
	return true
}

func (s *DataSet[T, E]) NextBatch(batch int64) ([]T, error) {
	if s.groupID > s.reader.NumRowGroups() || (s.groupID == s.reader.NumRowGroups() && s.cnt >= s.numRows) || s.numRows == 0 {
		return nil, merr.WrapErrServiceInternalMsg("has no more data")
	}

	if s.groupID == 0 || s.cnt >= s.numRows {
		err := s.nextGroup()
		if err != nil {
			return nil, err
		}
	}

	batch = Min(batch, s.numRows-s.cnt)
	result := make([]T, batch)
	_, _, err := s.cReader.ReadBatch(batch, result, nil, nil)
	if err != nil {
		return nil, err
	}

	s.cnt += batch
	return result, nil
}

func ReadData[T any, E interface {
	Value(int) T
	NullBitmapBytes() []byte
}](reader *file.Reader, value []T, validData []bool, numRows int64) (int64, error) {
	var offset int
	fileReader, err := pqarrow.NewFileReader(reader, pqarrow.ArrowReadProperties{}, memory.DefaultAllocator)
	// defer fileReader.ParquetReader().Close()
	if err != nil {
		mlog.Warn(context.TODO(), "create arrow parquet file reader failed", mlog.Err(err))
		return -1, err
	}
	schema, err := fileReader.Schema()
	if err != nil {
		mlog.Warn(context.TODO(), "can't schema from file", mlog.Err(err))
		return -1, err
	}
	for i, field := range schema.Fields() {
		// Spawn a new context to ignore cancellation from parental context.
		newCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer cancel()
		columnReader, err := fileReader.GetColumn(newCtx, i)
		if err != nil {
			mlog.Warn(context.TODO(), "get column reader failed", mlog.String("fieldName", field.Name), mlog.Err(err))
			return -1, err
		}
		chunked, err := columnReader.NextBatch(numRows)
		if err != nil {
			return -1, err
		}
		for _, chunk := range chunked.Chunks() {
			dataNums := chunk.Data().Len()
			reader, ok := chunk.(E)
			if !ok {
				mlog.Warn(context.TODO(), "the column data in parquet is not equal to field", mlog.String("fieldName", field.Name), mlog.String("actual type", chunk.DataType().Name()))
				return -1, merr.WrapErrImportFailedMsg("the column data in parquet is not equal to field: %s, but: %s", field.Name, chunk.DataType().Name())
			}
			nullBitset := bytesToBoolArray(dataNums, reader.NullBitmapBytes())
			for i := 0; i < dataNums; i++ {
				value[offset] = reader.Value(i)
				validData[offset] = nullBitset[i]
				offset++
			}
		}
	}
	return int64(offset), nil
}

// todo(smellthemoon): use byte to store valid_data
func bytesToBoolArray(length int, bytes []byte) []bool {
	bools := make([]bool, 0, length)

	for i := 0; i < length; i++ {
		bit := (bytes[uint(i)/8] & BitMask[byte(i)%8]) != 0
		bools = append(bools, bit)
	}

	return bools
}

var (
	BitMask        = [8]byte{1, 2, 4, 8, 16, 32, 64, 128}
	FlippedBitMask = [8]byte{254, 253, 251, 247, 239, 223, 191, 127}
)

// readNullableVectorData reads nullable vector data stored as Arrow Binary chunks.
// bytesPerVector is the byte size of each vector entry.
// Returns compact byte data (only valid vector entries) and validData bitmap.
//
// Arrow Binary array has 3 buffers:
//   - Buffer 0 (validity bitmap): bit i indicates whether row i is valid (non-null).
//   - Buffer 1 (offsets, int32): length n+1, offsets[i] is the start position of row i
//     in the values buffer, offsets[n] is the total byte length.
//   - Buffer 2 (values): concatenated raw bytes of all entries.
//
// Milvus's PayloadWriter uses BinaryBuilder.AppendNull() for null entries, which advances
// the offset without appending any bytes (offsets[i] == offsets[i+1]). Therefore null entries
// contribute zero bytes to the values buffer, and ValueBytes() returns a contiguous block
// containing only valid entries' data. This allows us to bulk-copy ValueBytes() directly
// instead of iterating per element with Value(i).
// We add a length assertion to guard against any future change that breaks this invariant.
func readNullableVectorData(column *arrow.Column, numRows int64, bytesPerVector int) ([]byte, []bool, error) {
	chunks := column.Data().Chunks()
	validCount := column.Len() - column.NullN()

	ret := make([]byte, validCount*bytesPerVector)
	validData := make([]bool, numRows)
	logicalOffset := 0
	dataOffset := 0
	for _, chunk := range chunks {
		binaryArray, ok := chunk.(*array.Binary)
		if !ok {
			return nil, nil, merr.WrapErrDataIntegrityMsg("expected Binary array for nullable vector, got %T", chunk)
		}
		chunkLen := binaryArray.Len()

		// Bulk copy all non-null vector data from this chunk
		chunkValidCount := chunkLen - binaryArray.NullN()
		if chunkValidCount > 0 {
			valueBytes := binaryArray.ValueBytes()
			expected := chunkValidCount * bytesPerVector
			if len(valueBytes) != expected {
				return nil, nil, merr.WrapErrDataIntegrityMsg(
					"unexpected valueBytes length for nullable vector: got %d, expected %d", len(valueBytes), expected)
			}
			copy(ret[dataOffset:dataOffset+len(valueBytes)], valueBytes)
			dataOffset += len(valueBytes)
		}

		// Build validData
		if binaryArray.NullN() == 0 {
			// compiler optimizes this range-based fill pattern
			for i := range validData[logicalOffset : logicalOffset+chunkLen] {
				validData[logicalOffset+i] = true
			}
		} else {
			for i := 0; i < chunkLen; i++ {
				validData[logicalOffset+i] = binaryArray.IsValid(i)
			}
		}
		logicalOffset += chunkLen
	}
	return ret, validData, nil
}
