package onlinestore

import (

"context"

"fmt"

"github.com/feast-dev/feast/go/internal/feast/registry"

"github.com/golang/protobuf/ptypes/timestamp"

"github.com/feast-dev/feast/go/protos/feast/serving"

"github.com/feast-dev/feast/go/protos/feast/types"

)

type FeatureData struct {

Reference serving.FeatureReferenceV2

Timestamp timestamp.Timestamp

Value types.Value

}

type OnlineStore interface {

// OnlineRead reads multiple features (specified in featureReferences) for multiple

// entity keys (specified in entityKeys) and returns an array of array of features,

// where each feature contains 3 fields:

// 1. feature Reference

// 2. feature event timestamp

// 3. feature value

// The inner array will have the same size as featureReferences,

// while the outer array will have the same size as entityKeys.

// TODO: Can we return [][]FeatureData, []timstamps, error

// instead and remove timestamp from FeatureData struct to mimic Python's code

// and reduces repeated memory storage for the same timstamp (which is stored as value and not as a pointer).

// Should each attribute in FeatureData be stored as a pointer instead since the current

// design forces value copied in OnlineRead + GetOnlineFeatures

// (array is destructed so we cannot use the same fields in each

// Feature object as pointers in GetOnlineFeaturesResponse)

// => allocate memory for each field once in OnlineRead

// and reuse them in GetOnlineFeaturesResponse?

OnlineRead(ctx context.Context, entityKeys []*types.EntityKey, featureViewNames []string, featureNames []string) ([][]FeatureData, error)

// Destruct must be call once user is done using OnlineStore

// This is to comply with the Connector since we have to close the plugin

Destruct()

}

func getOnlineStoreType(onlineStoreConfig map[string]interface{}) (string, bool) {

if onlineStoreType, ok := onlineStoreConfig["type"]; !ok {

// If online store type isn't specified, default to sqlite

return "sqlite", true

} else {

result, ok := onlineStoreType.(string)

return result, ok

}

}

func NewOnlineStore(config *registry.RepoConfig) (OnlineStore, error) {

onlineStoreType, ok := getOnlineStoreType(config.OnlineStore)

if !ok {

return nil, fmt.Errorf("could not get online store type from online store config: %+v", config.OnlineStore)

} else if onlineStoreType == "sqlite" {

onlineStore, err := NewSqliteOnlineStore(config.Project, config, config.OnlineStore)

return onlineStore, err

} else if onlineStoreType == "redis" {

onlineStore, err := NewRedisOnlineStore(config.Project, config, config.OnlineStore)

return onlineStore, err

} else {

return nil, fmt.Errorf("%s online store type is currently not supported; only redis and sqlite are supported", onlineStoreType)

}

}