<?php

declare(strict_types=1);

namespace App\Config;

/**
 * How far ahead a booking may be made.
 *
 * Measured from **today**, not from the day being booked: a cap relative to the chosen start date
 * can be pushed out simply by starting later, which is exactly what the previous
 * BookingSeries::MAX_MONTHS rule allowed (a series starting in six months could run to month
 * nine). It governs single bookings and series alike, which is why it lives here rather than on
 * BookingSeries.
 *
 * ROLE_ADMIN is exempt -- see BookingRequest::$unlimitedHorizon.
 */
final class BookingHorizon
{
    public const MONTHS = 3;

    /**
     * The last day that may still be booked. Inclusive.
     */
    public static function latest(?\DateTimeImmutable $today = null): \DateTimeImmutable
    {
        return ($today ?? new \DateTimeImmutable('today'))
            ->setTime(0, 0)
            ->modify(\sprintf('+%d months', self::MONTHS));
    }
}