package segments

import (
	"bytes"
	"context"
	"encoding/binary"
	"io"
	"strconv"

	"github.com/milvus-io/milvus-proto/go-api/v3/schemapb"
	"github.com/milvus-io/milvus/internal/querycoordv2/params"
	"github.com/milvus-io/milvus/internal/querynodev2/segments/metricsutil"
	"github.com/milvus-io/milvus/internal/storage"
	"github.com/milvus-io/milvus/internal/util/indexparamcheck"
	"github.com/milvus-io/milvus/internal/util/vecindexmgr"
	"github.com/milvus-io/milvus/pkg/v3/common"
	"github.com/milvus-io/milvus/pkg/v3/mlog"
	"github.com/milvus-io/milvus/pkg/v3/mq/msgstream"
	"github.com/milvus-io/milvus/pkg/v3/proto/datapb"
	"github.com/milvus-io/milvus/pkg/v3/proto/internalpb"
	"github.com/milvus-io/milvus/pkg/v3/proto/querypb"
	"github.com/milvus-io/milvus/pkg/v3/util/merr"
	"github.com/milvus-io/milvus/pkg/v3/util/typeutil"
)

func GetPkField(schema *schemapb.CollectionSchema) *schemapb.FieldSchema {
	for _, field := range schema.GetFields() {
		if field.GetIsPrimaryKey() {
			return field
		}
	}
	return nil
}

// TODO: remove this function to proper file
// GetPrimaryKeys would get primary keys by insert messages
func GetPrimaryKeys(msg *msgstream.InsertMsg, schema *schemapb.CollectionSchema) ([]storage.PrimaryKey, error) {
	if msg.IsRowBased() {
		return getPKsFromRowBasedInsertMsg(msg, schema)
	}
	return getPKsFromColumnBasedInsertMsg(msg, schema)
}

func getPKsFromRowBasedInsertMsg(msg *msgstream.InsertMsg, schema *schemapb.CollectionSchema) ([]storage.PrimaryKey, error) {
	offset := 0
	for _, field := range schema.Fields {
		if field.IsPrimaryKey {
			break
		}
		switch field.DataType {
		case schemapb.DataType_Bool:
			offset++
		case schemapb.DataType_Int8:
			offset++
		case schemapb.DataType_Int16:
			offset += 2
		case schemapb.DataType_Int32:
			offset += 4
		case schemapb.DataType_Timestamptz, schemapb.DataType_Int64:
			offset += 8
		case schemapb.DataType_Float:
			offset += 4
		case schemapb.DataType_Double:
			offset += 8
		case schemapb.DataType_FloatVector:
			for _, t := range field.TypeParams {
				if t.Key == common.DimKey {
					dim, err := strconv.Atoi(t.Value)
					if err != nil {
						return nil, merr.WrapErrParameterInvalidMsg("strconv wrong on get dim, err = %s", err)
					}
					offset += dim * 4
					break
				}
			}
		case schemapb.DataType_BinaryVector:
			for _, t := range field.TypeParams {
				if t.Key == common.DimKey {
					dim, err := strconv.Atoi(t.Value)
					if err != nil {
						return nil, merr.WrapErrParameterInvalidMsg("strconv wrong on get dim, err = %s", err)
					}
					offset += dim / 8
					break
				}
			}
		case schemapb.DataType_Float16Vector:
			for _, t := range field.TypeParams {
				if t.Key == common.DimKey {
					dim, err := strconv.Atoi(t.Value)
					if err != nil {
						return nil, merr.WrapErrParameterInvalidMsg("strconv wrong on get dim, err = %s", err)
					}
					offset += dim * 2
					break
				}
			}
		case schemapb.DataType_BFloat16Vector:
			for _, t := range field.TypeParams {
				if t.Key == common.DimKey {
					dim, err := strconv.Atoi(t.Value)
					if err != nil {
						return nil, merr.WrapErrParameterInvalidMsg("strconv wrong on get dim, err = %s", err)
					}
					offset += dim * 2
					break
				}
			}
		case schemapb.DataType_SparseFloatVector:
			return nil, merr.WrapErrParameterInvalidMsg("SparseFloatVector not support in row based message")
		}
	}

	mlog.Info(context.TODO(), strconv.FormatInt(int64(offset), 10))
	blobReaders := make([]io.Reader, len(msg.RowData))
	for i, blob := range msg.RowData {
		blobReaders[i] = bytes.NewReader(blob.GetValue()[offset : offset+8])
	}
	pks := make([]storage.PrimaryKey, len(blobReaders))

	for i, reader := range blobReaders {
		var int64PkValue int64
		err := binary.Read(reader, common.Endian, &int64PkValue)
		if err != nil {
			mlog.Warn(context.TODO(), "binary read blob value failed", mlog.Err(err))
			return nil, err
		}
		pks[i] = storage.NewInt64PrimaryKey(int64PkValue)
	}

	return pks, nil
}

func getPKsFromColumnBasedInsertMsg(msg *msgstream.InsertMsg, schema *schemapb.CollectionSchema) ([]storage.PrimaryKey, error) {
	primaryFieldSchema, err := typeutil.GetPrimaryFieldSchema(schema)
	if err != nil {
		return nil, err
	}

	primaryFieldData, err := typeutil.GetPrimaryFieldData(msg.GetFieldsData(), primaryFieldSchema)
	if err != nil {
		return nil, err
	}

	pks, err := storage.ParseFieldData2PrimaryKeys(primaryFieldData)
	if err != nil {
		return nil, err
	}

	return pks, nil
}

// mergeRequestCost merge the costs of request, the cost may come from different worker in same channel
// or different channel in same collection, for now we just choose the part with the highest response time
func mergeRequestCost(requestCosts []*internalpb.CostAggregation) *internalpb.CostAggregation {
	var result *internalpb.CostAggregation
	for _, cost := range requestCosts {
		if result == nil || result.ResponseTime < cost.ResponseTime {
			result = cost
		}
	}

	return result
}

// getSegmentMetricLabel returns the label for segment metrics.
func getSegmentMetricLabel(segment Segment) metricsutil.SegmentLabel {
	return metricsutil.SegmentLabel{
		DatabaseName:  segment.DatabaseName(),
		ResourceGroup: segment.ResourceGroup(),
	}
}

func FilterZeroValuesFromSlice(intVals []int64) []int64 {
	var result []int64
	for _, value := range intVals {
		if value != 0 {
			result = append(result, value)
		}
	}
	return result
}

func GetSegmentRelatedDataSize(segment Segment) int64 {
	if segment.Type() == SegmentTypeSealed {
		return calculateSegmentLogSize(segment.LoadInfo())
	}
	return segment.MemSize()
}

func calculateSegmentLogSize(segmentLoadInfo *querypb.SegmentLoadInfo) int64 {
	segmentSize := int64(0)

	for _, fieldBinlog := range segmentLoadInfo.BinlogPaths {
		segmentSize += getFieldSizeFromFieldBinlog(fieldBinlog)
	}

	// Get size of state data
	for _, fieldBinlog := range segmentLoadInfo.Statslogs {
		segmentSize += getFieldSizeFromFieldBinlog(fieldBinlog)
	}

	// Get size of delete data
	for _, fieldBinlog := range segmentLoadInfo.Deltalogs {
		segmentSize += getFieldSizeFromFieldBinlog(fieldBinlog)
	}

	return segmentSize
}

func calculateSegmentMemorySize(segmentLoadInfo *querypb.SegmentLoadInfo) int64 {
	segmentSize := int64(0)

	for _, fieldBinlog := range segmentLoadInfo.BinlogPaths {
		segmentSize += getBinlogDataMemorySize(fieldBinlog)
	}

	for _, fieldBinlog := range segmentLoadInfo.Statslogs {
		segmentSize += getBinlogDataMemorySize(fieldBinlog)
	}

	for _, fieldBinlog := range segmentLoadInfo.Deltalogs {
		segmentSize += getBinlogDataMemorySize(fieldBinlog)
	}

	return segmentSize
}

func getFieldSizeFromFieldBinlog(fieldBinlog *datapb.FieldBinlog) int64 {
	fieldSize := int64(0)
	for _, binlog := range fieldBinlog.Binlogs {
		fieldSize += binlog.LogSize
	}

	return fieldSize
}

func getFieldSchema(schema *schemapb.CollectionSchema, fieldID int64) (*schemapb.FieldSchema, error) {
	for _, field := range schema.Fields {
		if field.FieldID == fieldID {
			return field, nil
		}
	}
	for _, structArrayField := range schema.StructArrayFields {
		for _, subField := range structArrayField.Fields {
			if subField.FieldID == fieldID {
				return subField, nil
			}
		}
	}
	return nil, merr.WrapErrFieldNotFound(fieldID, "not in schema")
}

func isIndexMmapEnable(fieldSchema *schemapb.FieldSchema, indexInfo *querypb.FieldIndexInfo) bool {
	enableMmap, exist := common.IsMmapIndexEnabled(indexInfo.IndexParams...)
	// fast path for returning disabled, need to perform index type check for enabled case
	if exist && !enableMmap {
		return enableMmap
	}
	indexType := common.GetIndexType(indexInfo.IndexParams)
	var indexSupportMmap bool
	// var defaultEnableMmap bool
	if typeutil.IsVectorType(fieldSchema.GetDataType()) {
		indexSupportMmap = vecindexmgr.GetVecIndexMgrInstance().IsMMapSupported(indexType)
		enableMmap = params.Params.QueryNodeCfg.MmapVectorIndex.GetAsBool() || enableMmap
	} else {
		indexSupportMmap = indexparamcheck.IsScalarMmapIndex(indexType)
		enableMmap = params.Params.QueryNodeCfg.MmapScalarIndex.GetAsBool() || enableMmap
	}
	return indexSupportMmap && enableMmap
}

// Except accepting whether the raw data is loaded in mmap or not, it also affects the stats index such as
// text match index and json key stats index.
func isDataMmapEnable(fieldSchema *schemapb.FieldSchema) bool {
	enableMmap, exist := common.IsMmapDataEnabled(fieldSchema.GetTypeParams()...)
	if exist {
		return enableMmap
	}
	if typeutil.IsVectorType(fieldSchema.GetDataType()) {
		return params.Params.QueryNodeCfg.MmapVectorField.GetAsBool()
	}
	return params.Params.QueryNodeCfg.MmapScalarField.GetAsBool()
}

func isGrowingMmapEnable() bool {
	return params.Params.QueryNodeCfg.GrowingMmapEnabled.GetAsBool()
}

// getFieldWarmupPolicy returns the warmup policy for field data loading.
// Priority: field TypeParams (propagated from collection-level by QueryCoord, including autoWarmupForNonPKIsolationCollection) > global config
func getFieldWarmupPolicy(fieldSchema *schemapb.FieldSchema) string {
	// Check field TypeParams (collection-level warmup.scalarField/warmup.vectorField
	// and autoWarmupForNonPKIsolationCollection are propagated to field TypeParams by QueryCoord)
	policy, exist := common.GetWarmupPolicy(fieldSchema.GetTypeParams()...)
	if exist {
		return policy
	}
	// Fall back to global config
	if typeutil.IsVectorType(fieldSchema.GetDataType()) {
		return params.Params.QueryNodeCfg.TieredWarmupVectorField.GetValue()
	}
	return params.Params.QueryNodeCfg.TieredWarmupScalarField.GetValue()
}

// getIndexWarmupPolicy returns the warmup policy for index loading.
// Priority: index params (propagated from collection-level by QueryCoord, including autoWarmupForNonPKIsolationCollection) > global config
func getIndexWarmupPolicy(fieldSchema *schemapb.FieldSchema, indexInfo *querypb.FieldIndexInfo) string {
	// Check index params (collection-level warmup.scalarIndex/warmup.vectorIndex
	// and autoWarmupForNonPKIsolationCollection are propagated to index params by QueryCoord)
	policy, exist := common.GetWarmupPolicy(indexInfo.IndexParams...)
	if exist {
		return policy
	}
	// Fall back to global config
	if typeutil.IsVectorType(fieldSchema.GetDataType()) {
		return params.Params.QueryNodeCfg.TieredWarmupVectorIndex.GetValue()
	}
	return params.Params.QueryNodeCfg.TieredWarmupScalarIndex.GetValue()
}

// getScalarDataWarmupPolicy returns the warmup policy for scalar data, but also include json key stats and text match.
// Priority: field TypeParams (propagated from collection-level by QueryCoord, including autoWarmupForNonPKIsolationCollection) > global config
func getScalarDataWarmupPolicy(fieldSchema *schemapb.FieldSchema) string {
	// Check field TypeParams (collection-level warmup.scalarField and autoWarmupForNonPKIsolationCollection are propagated by QueryCoord)
	policy, exist := common.GetWarmupPolicy(fieldSchema.GetTypeParams()...)
	if exist {
		return policy
	}
	return params.Params.QueryNodeCfg.TieredWarmupScalarField.GetValue()
}

// isExternalCollectionLazyLoad checks if all external fields in the schema can
// avoid eager loading during segment load.
func isExternalCollectionLazyLoad(schema *schemapb.CollectionSchema) bool {
	resolver := typeutil.NewStorageColumnResolver(schema)
	if resolver.IsMilvusTable() && HasExternalPrimaryKey(schema) {
		// Real-PK milvus-table segments always load the source PK column and
		// source insert timestamps eagerly so source deltas preserve
		// delete/reinsert ordering.
		return false
	}
	for _, field := range schema.GetFields() {
		if !resolver.IsSourceDataField(field) {
			continue
		}
		policy := getFieldWarmupPolicy(field)
		if policy != common.WarmupDisable {
			return false
		}
	}
	return true
}

// GetVirtualPK generates a virtual primary key from segmentID and offset.
// Delegates to typeutil, the single source of truth for the virtual PK layout.
func GetVirtualPK(segmentID int64, offset int64) int64 {
	return typeutil.GetVirtualPK(segmentID, offset)
}

// ExtractSegmentIDFromVirtualPK extracts the segmentID from a virtual PK.
func ExtractSegmentIDFromVirtualPK(virtualPK int64) int64 {
	return typeutil.ExtractSegmentIDFromVirtualPK(virtualPK)
}

// ExtractOffsetFromVirtualPK extracts the offset from a virtual PK.
func ExtractOffsetFromVirtualPK(virtualPK int64) int64 {
	return typeutil.ExtractOffsetFromVirtualPK(virtualPK)
}

// IsVirtualPKFromSegment checks if a virtual PK belongs to the given segment.
func IsVirtualPKFromSegment(virtualPK int64, segmentID int64) bool {
	return typeutil.IsVirtualPKFromSegment(virtualPK, segmentID)
}

// IsExternalField checks if a field is an external field (data stored externally).
func IsExternalField(field *schemapb.FieldSchema) bool {
	return field.GetExternalField() != ""
}

// HasExternalPrimaryKey reports whether the loaded collection schema uses a
// user primary key instead of the milvus-table virtual primary key.
func HasExternalPrimaryKey(schema *schemapb.CollectionSchema) bool {
	if schema == nil {
		return false
	}
	for _, field := range schema.GetFields() {
		if field.GetIsPrimaryKey() {
			return field.GetName() != common.VirtualPKFieldName
		}
	}
	return false
}