package main

import (
	"fmt"
	"github.com/go-playground/locales/en"
	ut "github.com/go-playground/universal-translator"
	"github.com/go-playground/validator/v10"
	en_translations "github.com/go-playground/validator/v10/translations/en"
	"reflect"
	"regexp"
	"strings"
)


type Student struct {
	Name      string    `json:"name" validate:"omitempty,noSplChars"`
}
func main() {
	bob := &Student{
		Name: "*^*(&^*&",
	}

	appValidator := validator.New()
	_ = appValidator.RegisterValidation("noSplChars", validateNoSplChars)

	appValidator.RegisterTagNameFunc(func(fld reflect.StructField) string {
		name := strings.SplitN(fld.Tag.Get("json"), ",", 2)[0]

		if name == "-" {
			return ""
		}

		return name
	})

	err := appValidator.Struct(bob)
	if err != nil{

		validationErrors := err.(validator.ValidationErrors)
		fmt.Println("validationErrors",validationErrors)
	}


	english := en.New()
	uni := ut.New(english, english)
	translator, _ := uni.GetTranslator("en")
	_ = en_translations.RegisterDefaultTranslations(appValidator, translator)
	errStartsWith := "Field - `{0}` should starts with alpha numeric"
	addTranslation("should_start_with_alpha_numeric", errStartsWith, appValidator, &translator)
	print("done")
}

func addTranslation(tag string, errMessage string, appValidator *validator.Validate, translator *ut.Translator) {
	registerFn := func(ut ut.Translator) error {
		return ut.Add(tag, errMessage, true)
	}

	transFn := func(ut ut.Translator, fe validator.FieldError) string       {
		param := fe.Param()
		tag := fe.Tag()

		t, err := ut.T(tag, fe.Field(), param)
		if err != nil {
			return fe.(error).Error()
		}
		return t
	}

	_ = appValidator.RegisterTranslation(tag, *translator, registerFn, transFn)

}


func validateNoSplChars(fl validator.FieldLevel) bool {
	stringField := fl.Field().String()

	regex, _ := regexp.Compile("[a-zA-Z0-9].*$")
	result := regex.MatchString(stringField)
	return result
}