package db

import (
	"fmt"
	"path"

	"github.com/syndtr/goleveldb/leveldb"
	"github.com/syndtr/goleveldb/leveldb/errors"
	"github.com/syndtr/goleveldb/leveldb/opt"

	. "github.com/tendermint/go-common"
)

func init() {
	dbCreator := func(name string, dir string) (DB, error) {
		return NewGoLevelDB(name, dir)
	}
	registerDBCreator(LevelDBBackendStr, dbCreator, false)
	registerDBCreator(GoLevelDBBackendStr, dbCreator, false)
}

type GoLevelDB struct {
	db *leveldb.DB
}

func NewGoLevelDB(name string, dir string) (*GoLevelDB, error) {
	dbPath := path.Join(dir, name+".db")
	db, err := leveldb.OpenFile(dbPath, nil)
	if err != nil {
		return nil, err
	}
	database := &GoLevelDB{db: db}
	return database, nil
}

func (db *GoLevelDB) Get(key []byte) []byte {
	res, err := db.db.Get(key, nil)
	if err != nil {
		if err == errors.ErrNotFound {
			return nil
		} else {
			PanicCrisis(err)
		}
	}
	return res
}

func (db *GoLevelDB) Set(key []byte, value []byte) {
	err := db.db.Put(key, value, nil)
	if err != nil {
		PanicCrisis(err)
	}
}

func (db *GoLevelDB) SetSync(key []byte, value []byte) {
	err := db.db.Put(key, value, &opt.WriteOptions{Sync: true})
	if err != nil {
		PanicCrisis(err)
	}
}

func (db *GoLevelDB) Delete(key []byte) {
	err := db.db.Delete(key, nil)
	if err != nil {
		PanicCrisis(err)
	}
}

func (db *GoLevelDB) DeleteSync(key []byte) {
	err := db.db.Delete(key, &opt.WriteOptions{Sync: true})
	if err != nil {
		PanicCrisis(err)
	}
}

func (db *GoLevelDB) DB() *leveldb.DB {
	return db.db
}

func (db *GoLevelDB) Close() {
	db.db.Close()
}

func (db *GoLevelDB) Print() {
	str, _ := db.db.GetProperty("leveldb.stats")
	fmt.Printf("%v\n", str)

	iter := db.db.NewIterator(nil, nil)
	for iter.Next() {
		key := iter.Key()
		value := iter.Value()
		fmt.Printf("[%X]:\t[%X]\n", key, value)
	}
}

func (db *GoLevelDB) Stats() map[string]string {
	keys := []string{
		"leveldb.num-files-at-level{n}",
		"leveldb.stats",
		"leveldb.sstables",
		"leveldb.blockpool",
		"leveldb.cachedblock",
		"leveldb.openedtables",
		"leveldb.alivesnaps",
		"leveldb.aliveiters",
	}

	stats := make(map[string]string)
	for _, key := range keys {
		str, err := db.db.GetProperty(key)
		if err == nil {
			stats[key] = str
		}
	}
	return stats
}

func (db *GoLevelDB) Iterator() Iterator {
	return db.db.NewIterator(nil, nil)
}

func (db *GoLevelDB) NewBatch() Batch {
	batch := new(leveldb.Batch)
	return &goLevelDBBatch{db, batch}
}

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

type goLevelDBBatch struct {
	db    *GoLevelDB
	batch *leveldb.Batch
}

func (mBatch *goLevelDBBatch) Set(key, value []byte) {
	mBatch.batch.Put(key, value)
}

func (mBatch *goLevelDBBatch) Delete(key []byte) {
	mBatch.batch.Delete(key)
}

func (mBatch *goLevelDBBatch) Write() {
	err := mBatch.db.db.Write(mBatch.batch, nil)
	if err != nil {
		PanicCrisis(err)
	}
}