package util

import (
	"errors"
	"regexp"
	"unicode"

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

var (
	emailRegex = regexp.MustCompile(`^[a-zA-Z0-9._%+\-]+@[a-zA-Z0-9.\-]+\.[a-zA-Z]{2,}$`)
	phoneRegex = regexp.MustCompile(`^\+?[1-9]\d{6,14}$`)
)

func IsValidEmail(email string) bool {
	return emailRegex.MatchString(email)
}

func IsValidPhone(phone string) bool {
	return phoneRegex.MatchString(phone)
}

// ValidatePassword 校验密码强度：至少 8 位，且包含大写字母、小写字母和数字。
func ValidatePassword(password string) string {
	if len(password) < 8 {
		return "密码长度不能少于8个字符"
	}
	if len(password) > 72 {
		return "密码长度不能超过72个字符"
	}
	var hasUpper, hasLower, hasDigit bool
	for _, c := range password {
		switch {
		case unicode.IsUpper(c):
			hasUpper = true
		case unicode.IsLower(c):
			hasLower = true
		case unicode.IsDigit(c):
			hasDigit = true
		}
	}
	if !hasUpper || !hasLower || !hasDigit {
		return "密码必须包含大写字母、小写字母和数字"
	}
	return ""
}

// IsDuplicateEntryErr 判断是否为 MySQL 唯一索引冲突错误 (errno 1062)。
func IsDuplicateEntryErr(err error) bool {
	var me *mysql.MySQLError
	return errors.As(err, &me) && me.Number == 1062
}

func NormalizePage(page, pageSize int64) (int64, int64) {
	if page <= 0 {
		page = 1
	}
	if pageSize <= 0 {
		pageSize = 20
	}
	if pageSize > 100 {
		pageSize = 100
	}
	return page, pageSize
}