package factory

import (
	"fmt"
	"io"
	"sync"

	"git.x2erp.com/qdy/go-base/config"
	"git.x2erp.com/qdy/go-base/types"
	"git.x2erp.com/qdy/go-db/drivers"
	"git.x2erp.com/qdy/go-db/functions"

	"github.com/jmoiron/sqlx"
)

type DBFactory struct {
	db *sqlx.DB
}

var (
	instanceDBFactory *DBFactory
	once              sync.Once
)

// GetDBFactory 创建数据库工厂单例
func GetDBFactory() (*DBFactory, error) {
	var initErr error
	var msg = "DBFactory instance retrieved from memory.\n"

	once.Do(func() {
		// 使用配置单例
		cfg := config.GetConfig()

		// 检查配置初始化是否有错误
		if err := config.GetInitError(); err != nil {
			initErr = fmt.Errorf("failed to load config: %v", err)
			return
		}

		// 检查数据库配置是否完整
		if !cfg.IsDatabaseConfigured() {
			initErr = fmt.Errorf("database configuration is incomplete")
			return
		}

		// 显示所支持的数据库驱动
		driversStr := drivers.GetAllDrivers()
		fmt.Printf("Available database drivers: %v\n", driversStr)

		dbConfig := cfg.GetDatabase()
		dbType := dbConfig.Type

		// 获取对应的驱动
		dbDriver, err := drivers.Get(dbType)
		if err != nil {
			initErr = fmt.Errorf("failed to get database driver: %v", err)
			return
		}

		// 将内部 DBConfig 转换为 drivers.DBConfig
		driverConfig := drivers.DBConfig{
			Type:            dbConfig.Type,
			Host:            dbConfig.Host,
			Port:            dbConfig.Port,
			Username:        dbConfig.Username,
			Password:        dbConfig.Password,
			Database:        dbConfig.Database,
			MaxOpenConns:    dbConfig.MaxOpenConns,
			MaxIdleConns:    dbConfig.MaxIdleConns,
			ConnMaxLifetime: dbConfig.ConnMaxLifetime,
		}

		// 创建数据库连接
		db, err := dbDriver.Open(driverConfig)
		if err != nil {
			initErr = fmt.Errorf("failed to open database connection: %v", err)
			return
		}

		// 测试连接
		if err := functions.TestConnection(db, dbType); err != nil {
			db.Close()
			initErr = fmt.Errorf("database connection test failed: %v", err)
			return
		}

		msg = "DBFactory is successfully created.\n"
		instanceDBFactory = &DBFactory{db: db}
	})

	if initErr != nil {
		return nil, initErr
	}

	fmt.Print(msg)

	return instanceDBFactory, nil
}

// GetDB 获取数据库连接（线程安全）
func (f *DBFactory) GetDB() *sqlx.DB {
	return f.db
}

// Close 关闭数据库连接
func (f *DBFactory) Close() error {
	if f.db != nil {
		err := f.db.Close()
		f.db = nil
		fmt.Println("Database connection closed gracefully")
		return err
	}
	return nil
}

// QueryToJSON 快捷查询，直接返回 JSON 字节流
func (f *DBFactory) QueryToJSON(sql string) *types.QueryResult {
	return functions.QueryToJSON(f.db, sql)
}

// QueryToCSV 快捷查询，直接返回 CSV 字符串（包含表头）
func (f *DBFactory) QueryToCSV(sql string) ([]byte, error) {
	return functions.QueryToCSV(f.db, sql)
}

// QueryWithColumns 快捷查询，返回完整结果（含列信息）
func (f *DBFactory) QueryWithColumns(sql string) *types.QueryResult {
	return functions.QueryWithColumns(f.db, sql)
}

// QueryDataOnly 快捷查询，返回纯数据（性能优先）
func (f *DBFactory) QueryDataOnly(sql string) *types.QueryResult {
	return functions.QueryDataOnly(f.db, sql)
}

// QueryCSV 快捷查询，返回 CSV 格式结果（支持自定义是否包含表头）
func (f *DBFactory) QueryCSV(sql string, includeHeader bool) *types.QueryResult {
	return functions.QueryCSV(f.db, sql, includeHeader)
}

// QueryCSVStream 快捷流式输出 CSV（直接写入 io.Writer，适合大文件）
func (f *DBFactory) QueryCSVStream(sql string, w io.Writer, includeHeader bool) (int, error) {
	return functions.QueryCSVStream(f.db, sql, w, includeHeader)
}

// ExecuteDDL 快捷执行DDL语句
func (f *DBFactory) ExecuteDDL(ddlSQL string) error {
	return functions.ExecuteDDL(f.db, ddlSQL)
}

// ExecuteDDLWithTx 快捷在事务中执行DDL语句
func (f *DBFactory) ExecuteDDLWithTx(ddlSQL string) error {
	return functions.ExecuteDDLWithTx(f.db, ddlSQL)
}

// ExecuteMultipleDDL 快捷执行多个DDL语句
func (f *DBFactory) ExecuteMultipleDDL(ddlSQLs []string) error {
	return functions.ExecuteMultipleDDL(f.db, ddlSQLs)
}

// GetAvailableDrivers 获取可用的数据库驱动
func (f *DBFactory) GetAvailableDrivers() []string {
	return drivers.GetAllDrivers()
}

func (f *DBFactory) TestConnection(dbType string) error {
	return functions.TestConnection(f.db, dbType)
}