package http

import (
	"fmt"
	"reflect"

	"github.com/go-playground/validator/v10"
)

type fieldError struct {
	Field   string
	Message string
}

func NewValidator() *validator.Validate {
	validate := validator.New()
	validate.RegisterTagNameFunc(func(fld reflect.StructField) string {
		if fld.Tag.Get("validation_name") != "" {
			return fld.Tag.Get("validation_name")
		} else {
			return fld.Tag.Get("json")
		}
	})

	return validate
}

func validationErrorFormater(errs validator.ValidationErrors) []fieldError {
	fieldErrs := make([]fieldError, 0)

	if errs != nil {
		for _, err := range errs {
			fieldErrs = append(
				fieldErrs,
				fieldError{
					Field:   err.Field(),
					Message: msgForTag(err.Tag(), err.Field(), err.Param()),
				},
			)
		}
		return fieldErrs
	}

	return nil
}

func msgForTag(tag, field, param string) string {
	switch tag {
	case "required":
		return fmt.Sprintf("%s is required", field)
	case "email":
		return "email is invalid"
	case "min":
		return fmt.Sprintf("The length of %s must be at least %s", field, param)
	case "max":
		return fmt.Sprintf("The length of %s must be at most %s", field, param)
	default:
		return fmt.Sprintf("%s is invalid", field)
	}
}