package storage

import (
	"fmt"
	"path/filepath"
)

// EngineConfig 存储引擎配置
type EngineConfig struct {
	// 持久化配置
	PersistenceType PersistenceType // 持久化类型
	PersistenceDir  string          // 持久化目录
	SyncEvery       int             // 每写入多少条数据同步一次
	// memory engine特有配置
	MemLen int
	// BoltDB特有配置
	BoltDBFilename string        // BoltDB文件名
	BoltDBOptions  *BoltDBConfig // BoltDB选项
}

// NewStorageEngine 创建一个新的存储引擎
func NewStorageEngine(config EngineConfig) (StorageEngine, error) {
	var engine StorageEngine
	var err error

	switch config.PersistenceType {
	case PersistenceTypeNone, PersistenceTypeWAL:
		// 创建内存存储引擎
		memEngine := NewMemoryEngine(config.MemLen)

		// 如果需要持久化，启用WAL
		if config.PersistenceType == PersistenceTypeWAL {
			err = memEngine.EnablePersistence(PersistenceConfig{
				Type:      PersistenceTypeWAL,
				Directory: config.PersistenceDir,
				SyncEvery: config.SyncEvery,
			})
			if err != nil {
				return nil, fmt.Errorf("failed to enable WAL persistence: %v", err)
			}
		}

		engine = memEngine

	case PersistenceTypeBoltDB:
		// 创建BoltDB存储引擎
		boltDBPath := filepath.Join(config.PersistenceDir, config.BoltDBFilename)
		if config.BoltDBFilename == "" {
			boltDBPath = filepath.Join(config.PersistenceDir, "gotidb.db")
		}

		boltDBConfig := config.BoltDBOptions
		if boltDBConfig == nil {
			boltDBConfig = &BoltDBConfig{
				FilePath: boltDBPath,
			}
		} else {
			boltDBConfig.FilePath = boltDBPath
		}

		boltEngine, err := NewBoltDBEngine(*boltDBConfig)
		if err != nil {
			return nil, fmt.Errorf("failed to create BoltDB engine: %v", err)
		}

		engine = boltEngine

	default:
		return nil, fmt.Errorf("unsupported persistence type: %s", config.PersistenceType)
	}

	return engine, nil
}