package leveldb

import (
	"errors"

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

var _db *leveldb.DB
var config *Config

func Init(conf *Config) {
	config = conf
	if config == nil {
		config = &Config{
			Path: "./",
		}
	}
}

func New() (*leveldb.DB, error) {
	if _db != nil {
		return _db, nil
	}
	db, err := leveldb.OpenFile(config.Path, nil)
	if err != nil {
		return nil, err
	}
	_db = db
	return _db, nil
}

func Close() {
	if _db != nil {
		_db.Close()
	}
	_db = nil
}

func Get(key *string) (*[]byte, error) {
	db, err := New()
	if err != nil {
		return nil, err
	}
	if db == nil {
		return nil, errors.New("leveldb is nil")
	}
	ret, err := db.Has([]byte(*key), &opt.ReadOptions{
		DontFillCache: false,
		Strict:        0,
	})
	if err != nil {
		return nil, errors.New("key检查异常")
	}

	if !ret {
		return nil, errors.New("key不存在")
	}

	val, err := db.Get([]byte(*key), nil)
	if err != nil {
		return nil, err
	}

	if len(val) == 0 {
		return nil, errors.New("key empty")
	}
	return &val, nil
}

func Put(key *string, payload *[]byte) error {
	db, err := New()
	if err != nil {
		return err
	}
	if db == nil {
		return errors.New("leveldb is busy now")
	}

	if err := db.Put([]byte(*key), *payload, nil); err != nil {
		return err
	}
	return nil
}

func Delete(key *string) error {
	db, err := New()
	if err != nil {
		return err
	}
	if db == nil {
		return errors.New("leveldb is busy now")
	}

	ret, err := db.Has([]byte(*key), &opt.ReadOptions{
		DontFillCache: false,
		Strict:        0,
	})
	if err != nil {
		return err
	}

	if !ret {
		return nil
	}

	if err := db.Delete([]byte(*key), nil); err != nil {
		return err
	}
	return nil
}