// Copyright (C) 2018 Marius Schellenberger

package store

import "github.com/boltdb/bolt"

const defaultBoltBucket = "default"

type BoltStore struct {
	Marshaler
	db *bolt.DB
}

func NewBoltStore(file string, m Marshaler) (bs *BoltStore, err error) {
	if m == nil {
		m = NewGOB()
	}
	db, err := bolt.Open(file, 0666, nil)
	if err != nil {
		return
	}
	if err = db.Update(func(tx *bolt.Tx) error {
		if _, err := tx.CreateBucketIfNotExists([]byte(defaultBoltBucket)); err != nil {
			return err
		}
		return nil
	}); err != nil {
		return
	}
	bs = &BoltStore{m, db}
	return
}

func (bs *BoltStore) Get(key string, v interface{}) (err error) {
	err = bs.db.View(func(tx *bolt.Tx) error {
		b := tx.Bucket([]byte(defaultBoltBucket)).Get([]byte(key))
		if b == nil {
			return ErrKeyNotFound
		}
		if v != nil {
			return bs.Unmarshal(b, v)
		}
		return nil
	})
	return
}

func (bs *BoltStore) Set(key string, v interface{}) error {
	return bs.db.Update(func(tx *bolt.Tx) error {
		b, err := bs.Marshal(v)
		if err != nil {
			return err
		}
		return tx.Bucket([]byte(defaultBoltBucket)).Put([]byte(key), b)
	})
}

func (bs *BoltStore) ForEach(f func(string, []byte) error) error {
	return bs.db.View(func(tx *bolt.Tx) error {
		return tx.Bucket([]byte(defaultBoltBucket)).ForEach(func(k, v []byte) error {
			return f(string(k), v)
		})
	})
}

func (bs *BoltStore) Delete(key string) error {
	return bs.db.Update(func(tx *bolt.Tx) error {
		return tx.Bucket([]byte(defaultBoltBucket)).Delete([]byte(key))
	})
}

func (bs *BoltStore) Close() error {
	return bs.db.Close()
}