package heartwood

import (
	"github.com/boltdb/bolt"
)

// Interface

type BoltDB interface {
	Setup() error
	BatchCheckEventsExist(eventIDs []string) map[string]bool
	BatchWriteEvents(events []EventBlob) error
}

func NewKVDB(boltdb *bolt.DB) BoltDB {
	return &boltDB{db: boltdb}
}

type boltDB struct {
	db *bolt.DB
}

func (b *boltDB) Setup() error {
	return SetupBoltDB(b.db)
}

func (b *boltDB) BatchCheckEventsExist(eventIDs []string) map[string]bool {
	return BatchCheckEventsExist(b.db, eventIDs)
}

func (b *boltDB) BatchWriteEvents(events []EventBlob) error {
	return BatchWriteEvents(b.db, events)
}

func SetupBoltDB(boltdb *bolt.DB) error {
	return boltdb.Update(func(tx *bolt.Tx) error {
		_, err := tx.CreateBucketIfNotExists([]byte(BucketName))
		return err
	})
}

// Functions

const BucketName string = "events"

type EventBlob struct {
	ID   string
	JSON string
}

func BatchCheckEventsExist(boltdb *bolt.DB, eventIDs []string) map[string]bool {
	existsMap := make(map[string]bool)

	boltdb.View(func(tx *bolt.Tx) error {
		bucket := tx.Bucket([]byte(BucketName))
		if bucket == nil {
			return nil
		}
		for _, id := range eventIDs {
			existsMap[id] = bucket.Get([]byte(id)) != nil
		}
		return nil
	})

	return existsMap
}

func BatchWriteEvents(boltdb *bolt.DB, events []EventBlob) error {
	return boltdb.Update(func(tx *bolt.Tx) error {
		bucket := tx.Bucket([]byte(BucketName))
		for _, event := range events {
			if err := bucket.Put(
				[]byte(event.ID), []byte(event.JSON),
			); err != nil {
				return err
			}
		}
		return nil
	})
}