package classes

import (
	"strings"
	"unicode/utf8"

	"git.golem15.com/golem15/sm-quizzes-plugin/models"
)

// MaxLength is the longest answer an open question accepts, in characters:
// its MaxLength when set and positive, else models.DefaultMaxLength.
func MaxLength(q models.Question) int {
	if q.MaxLength != nil && *q.MaxLength > 0 {
		return *q.MaxLength
	}
	return models.DefaultMaxLength
}

// CheckOpenText cleans a student's answer to an open question (D-04): it
// removes every NUL character (Postgres text refuses them) and the
// surrounding whitespace. A blank text is a FieldError text_required and a
// text longer than MaxLength(q) characters (runes, not bytes) is a
// FieldError text_too_long.
func CheckOpenText(text string, q models.Question) (string, error) {
	text = strings.TrimSpace(strings.ReplaceAll(text, "\x00", ""))
	if text == "" {
		return "", &FieldError{Field: "text", Key: "text_required"}
	}
	if utf8.RuneCountInString(text) > MaxLength(q) {
		return "", &FieldError{Field: "text", Key: "text_too_long"}
	}
	return text, nil
}