<?php
/**
 * Directory catalogue: two named booking-form fields.
 *
 * There is no third form property to assign. The commercial pack
 * replaces this file with a plan-sized occupancy list.
 *
 * @package Bookline
 */

declare( strict_types=1 );

namespace Bookline\Config;

use Bookline\Domain\BookingForm\BookingForm;
use Bookline\Domain\Edition\EditionDimension;
use Bookline\Domain\Edition\EditionLimitReached;

/**
 * Two named booking-form fields.
 *
 * @since 1.0.1
 */
final class BookingFormPlaces {

	/**
	 * Hydrate named fields from occupied slots (keys 1–2).
	 *
	 * @param array<int, BookingForm> $occupied_by_slot Slot number => occupant.
	 */
	public static function from_occupied( array $occupied_by_slot ): self {
		return new self(
			$occupied_by_slot[1] ?? null,
			$occupied_by_slot[2] ?? null
		);
	}

	/**
	 * Bind the two named booking-form fields.
	 *
	 * @param BookingForm|null $form_1 First form field.
	 * @param BookingForm|null $form_2 Second form field.
	 */
	public function __construct(
		private ?BookingForm $form_1 = null,
		private ?BookingForm $form_2 = null,
	) {}

	/**
	 * Occupy the first empty named field.
	 *
	 * @param BookingForm $form Incoming form.
	 * @return int Slot number 1–2.
	 *
	 * @throws EditionLimitReached When form_1 and form_2 are both set.
	 */
	public function place( BookingForm $form ): int {
		if ( null === $this->form_1 ) {
			$this->form_1 = $form;
			return 1;
		}
		if ( null === $this->form_2 ) {
			$this->form_2 = $form;
			return 2;
		}
		throw new EditionLimitReached( EditionDimension::BookingForm, 2 );
	}
}