class DateHeader

final class DateHeader extends AbstractHeader {
    private \DateTimeImmutable $dateTime;
    public function __construct(string $name, \DateTimeInterface $date) {
        parent::__construct($name);
        $this->setDateTime($date);
    }
    
    /**
     * @param \DateTimeInterface $body
     */
    public function setBody(mixed $body) : void {
        $this->setDateTime($body);
    }
    public function getBody() : \DateTimeImmutable {
        return $this->getDateTime();
    }
    public function getDateTime() : \DateTimeImmutable {
        return $this->dateTime;
    }
    
    /**
     * Set the date-time of the Date in this Header.
     *
     * If a DateTime instance is provided, it is converted to DateTimeImmutable.
     */
    public function setDateTime(\DateTimeInterface $dateTime) : void {
        $this->dateTime = \DateTimeImmutable::createFromInterface($dateTime);
    }
    public function getBodyAsString() : string {
        return $this->dateTime
            ->format(\DateTimeInterface::RFC2822);
    }

}