Card Expiration Parsing PD-2814

expiration.go

// Expiration wraps month and year of card expiration.
type Expiration struct {
	Month time.Month
	Year  int
}

// LocalDate returns LocalDate that is equal to expiration date.
func (e Expiration) LocalDate() LocalDate {
	return Date(e.Year, e.Month, 1)
}

func (e Expiration) String() string {
	return fmt.Sprintf("%02d/%d", e.Month, e.Year)
}

// StringShort returns short format of expiration date, e.g. 0422 for April
// 2022.
func (e Expiration) StringShort() string {
	return fmt.Sprintf("%02d%02d", e.Month, e.Year%expirationDefaultYear)
}

// ParseShort parses s as short format of expiration date returning error
// if any.
func (e *Expiration) ParseShort(s string) error {
	if len(s) != 4 {
		return errors.Errorf("unexpected length of expiration date %q", len(s))
	}
	m, err := strconv.Atoi(s[:2])
	if err != nil {
		return errors.Wrap(err, "bad month value")
	}
	y, err := strconv.Atoi(s[2:])
	if err != nil {
		return errors.Wrap(err, "bad year value")
	}
	e.Month = time.Month(m)
	e.Year = y + expirationDefaultYear
	return nil
}