package db_executor

import (
	"fmt"
	"xg_fetl/internal/models"

	_ "github.com/go-sql-driver/mysql"

	"xorm.io/xorm"
)

type DBExecutor interface {
	InitDB(dsn string) error
	QueryRowsAsMaps(sqlStr string) ([]map[string]string, error)
	GetColumnsAndRows(query string) ([]string, []map[string]interface{}, error)
	Close() error

	// 定义其他通用的方法
	GetDatabaseInfo(database string) (*models.DatabaseInfo, error)
	ReadTableFromDBWithPagination(tableName string, offset int, pageSize int) ([]string, [][]string, error)
	InsertRecordsToDB(tableName string, headers []string, records [][]string) error
}

type BaseExecutor struct {
	Engine *xorm.Engine
}

func (b *BaseExecutor) Close() error {
	return b.Engine.Close()
}

// InitDB 初始化数据库连接
func (b *BaseExecutor) InitDB(dsn string) error {
	engine, err := xorm.NewEngine("mysql", dsn)
	if err != nil {
		return fmt.Errorf("failed to initialize DB: %v", err)
	}
	b.Engine = engine
	return nil
}

// QueryRowsAsMaps 通用的查询方法，返回每行结果的映射
func (b *BaseExecutor) QueryRowsAsMaps(sqlStr string) ([]map[string]string, error) {
	results, err := b.Engine.QueryString(sqlStr)
	if err != nil {
		return nil, err
	}
	return results, nil // xorm 已经将每行结果映射为 map[string]interface{}
}

// GetColumnsAndRows 执行查询并返回字段名和结果集
func (b *BaseExecutor) GetColumnsAndRows(query string) ([]string, []map[string]interface{}, error) {
	rows, err := b.Engine.QueryInterface(query)
	if err != nil {
		return nil, nil, err
	}

	// 获取列名
	if len(rows) == 0 {
		return nil, nil, fmt.Errorf("no results found")
	}
	columns := make([]string, 0, len(rows[0]))
	for col := range rows[0] {
		columns = append(columns, col)
	}

	// 返回列名和结果集
	return columns, rows, nil
}

// 工厂函数，根据数据库类型创建相应的执行器
func NewDBExecutor(dbType string, dsn string) (DBExecutor, error) {
	switch dbType {
	case "mysql":
		engine, err := xorm.NewEngine("mysql", dsn)
		if err != nil {
			return nil, fmt.Errorf("failed to initialize DB: %v", err)
		}

		return &MySQLExecutor{BaseExecutor: BaseExecutor{Engine: engine}}, nil

	default:
		return nil, fmt.Errorf("unsupported database type: %s", dbType)
	}
}