package utils

import (
	"errors"
	"fmt"
)

type Driver string

const (
	DM    Driver = "dm"
	MySql Driver = "mysql"
)

var supportDriverMap = map[string]Driver{
	"mysql": MySql,
	"dm":    DM,
}

func GroupUnitFunc(driver string, column, delimiter, tableAlia string) (sqlStr string) {
	dbDriver, _ := getDriverInstance(driver)
	if delimiter == "" {
		delimiter = ","
	}
	if column == "" {
		column = "[UNKNOWN COLUMN]"
	}
	if tableAlia != "" {
		column = fmt.Sprintf("%s.%s", tableAlia, column)
	}
	switch dbDriver {
	case MySql:
		sqlStr = fmt.Sprintf("GROUP_CONCAT(%s SEPARATOR '%s')", column, delimiter)
	case DM:
		sqlStr = fmt.Sprintf("LISTAGG(%s, '%s') WITHIN GROUP (ORDER BY %s)", column, delimiter, column)
	default:
		sqlStr = fmt.Sprintf("GROUP_CONCAT(%s SEPARATOR '%s')", column, delimiter) // 默认使用 MySQL 的语法
	}
	return sqlStr
}

func getDriverInstance(driver string) (dbDriver Driver, err error) {
	if driver == "" {
		dbDriver = supportDriverMap[DbDriverName]
	}
	if currentDriver, ok := supportDriverMap[driver]; !ok {
		err = errors.New("不支持的数据库驱动类型")
		return
	} else {
		dbDriver = currentDriver
	}
	return
}

func NeedDateOrTimeFormat(driver string) bool {
	var dbDriver Driver
	if driver == "" {
		dbDriver = supportDriverMap[DbDriverName]
	} else {
		dbDriver, _ = getDriverInstance(driver)
	}
	if dbDriver == DM {
		return true
	}
	return false
}