package db

import . "github.com/tendermint/tmlibs/common"

type DB interface {
	Get([]byte) []byte
	Set([]byte, []byte)
	SetSync([]byte, []byte)
	Delete([]byte)
	DeleteSync([]byte)
	Close()
	NewBatch() Batch

	// For debugging
	Print()
	Iterator() Iterator
	Stats() map[string]string
}

type Batch interface {
	Set(key, value []byte)
	Delete(key []byte)
	Write()
}

type Iterator interface {
	Next() bool

	Key() []byte
	Value() []byte
}

//-----------------------------------------------------------------------------

const (
	LevelDBBackendStr   = "leveldb" // legacy, defaults to goleveldb.
	CLevelDBBackendStr  = "cleveldb"
	GoLevelDBBackendStr = "goleveldb"
	MemDBBackendStr     = "memdb"
)

type dbCreator func(name string, dir string) (DB, error)

var backends = map[string]dbCreator{}

func registerDBCreator(backend string, creator dbCreator, force bool) {
	_, ok := backends[backend]
	if !force && ok {
		return
	}
	backends[backend] = creator
}

func NewDB(name string, backend string, dir string) DB {
	db, err := backends[backend](name, dir)
	if err != nil {
		PanicSanity(Fmt("Error initializing DB: %v", err))
	}
	return db
}