<?php
/**
 * Capacity used for a service slot start.
 *
 * @package Bookline
 */

declare( strict_types=1 );

namespace Bookline\Domain\Booking;

use DateTimeImmutable;

/**
 * Aggregate attendees at a given service start_utc.
 *
 * @since 0.1.0
 */
final class SlotCapacity {

	/**
	 * Constructor.
	 *
	 * @param DateTimeImmutable $start_utc Slot start.
	 * @param int               $attendees Sum of attendees.
	 *
	 * @throws \Bookline\Domain\Shared\DomainException When invariants fail.
	 */
	public function __construct(
		private DateTimeImmutable $start_utc,
		private int $attendees,
	) {
	}

	/**
	 * Start utc.
	 *
	 * @since 0.1.0
	 */
	public function start_utc(): DateTimeImmutable {
		return $this->start_utc;
	}

	/**
	 * Attendees.
	 *
	 * @since 0.1.0
	 */
	public function attendees(): int {
		return $this->attendees;
	}
}