package bolt

import (
	"fmt"
	"time"

	bolt "go.etcd.io/bbolt"
)

// Compact 实现 Engine 接口
func (b *BoltEngine) Compact() error {
	b.mu.Lock()
	defer b.mu.Unlock()

	if !b.opened || b.closed {
		return fmt.Errorf("bolt engine not open")
	}

	// 执行数据库压缩
	if err := b.db.Sync(); err != nil {
		return fmt.Errorf("failed to sync database: %v", err)
	}

	// 更新统计信息
	b.stats.CompactionCount++
	b.stats.LastCompaction = time.Now()

	return nil
}

// Cleanup 实现 Engine 接口
func (b *BoltEngine) Cleanup() error {
	b.mu.Lock()
	defer b.mu.Unlock()

	if !b.opened || b.closed {
		return fmt.Errorf("bolt engine not open")
	}

	// 清理空序列
	err := b.db.Update(func(tx *bolt.Tx) error {
		indexBucket := tx.Bucket([]byte(indexBucketName))
		if indexBucket == nil {
			return fmt.Errorf("index bucket not found")
		}

		return indexBucket.ForEach(func(k, v []byte) error {
			seriesID := string(k)
			bucket := tx.Bucket([]byte(seriesBucketPrefix + seriesID))
			if bucket == nil {
				return nil
			}

			// 如果序列为空，删除它
			if bucket.Stats().KeyN == 0 {
				if err := tx.DeleteBucket([]byte(seriesBucketPrefix + seriesID)); err != nil {
					return fmt.Errorf("failed to delete empty series bucket: %v", err)
				}

				// 从索引中删除
				if err := indexBucket.Delete(k); err != nil {
					return fmt.Errorf("failed to delete series from index: %v", err)
				}
			}

			return nil
		})
	})

	if err != nil {
		return fmt.Errorf("failed to cleanup: %v", err)
	}

	// 更新序列数
	if err := b.updateSeriesCount(); err != nil {
		return fmt.Errorf("failed to update series count: %v", err)
	}

	return nil
}