//  Copyright (c) 2014 Couchbase, Inc.
//  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
//  except in compliance with the License. You may obtain a copy of the License at
//    http://www.apache.org/licenses/LICENSE-2.0
//  Unless required by applicable law or agreed to in writing, software distributed under the
//  License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
//  either express or implied. See the License for the specific language governing permissions
//  and limitations under the License.
package boltdb

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

type op struct {
	k []byte
	v []byte
}

type BoltDBBatch struct {
	store *BoltDBStore
	ops   []op
}

func newBoltDBBatch(store *BoltDBStore) *BoltDBBatch {
	rv := BoltDBBatch{
		store: store,
		ops:   make([]op, 0),
	}
	return &rv
}

func (i *BoltDBBatch) Set(key, val []byte) {
	i.ops = append(i.ops, op{key, val})
}

func (i *BoltDBBatch) Delete(key []byte) {
	i.ops = append(i.ops, op{key, nil})
}

func (i *BoltDBBatch) Execute() error {
	return i.store.db.Update(func(tx *bolt.Tx) error {
		b := tx.Bucket([]byte(i.store.bucket))

		for _, o := range i.ops {
			if o.v == nil {
				if err := b.Delete(o.k); err != nil {
					return err
				}
			} else {
				if err := b.Put(o.k, o.v); err != nil {
					return err
				}
			}
		}

		return nil
	})
}

func (i *BoltDBBatch) Close() error {
	return nil
}