<?php
/**
 * Selected service extra line for pricing.
 *
 * @package Bookline
 */

declare( strict_types=1 );

namespace Bookline\Domain\Pricing;

use Bookline\Domain\Shared\DomainException;

/**
 * Quantity × unit price for one extra on a booking draft.
 *
 * @since 0.1.0
 */
final class SelectedExtra {

	/**
	 * Constructor.
	 *
	 * @param Money $unit_price Unit price.
	 * @param int   $quantity   Quantity selected.
	 *
	 * @throws DomainException When quantity is invalid or price is negative.
	 */
	public function __construct(
		private Money $unit_price,
		private int $quantity,
	) {
		if ( $this->quantity < 1 ) {
			throw new DomainException( 'pricing.extra_quantity', 'Extra quantity must be at least 1.' );
		}
		if ( $this->unit_price->is_negative() ) {
			throw new DomainException( 'pricing.extra_price_negative', 'Extra unit price must not be negative.' );
		}
	}

	/**
	 * Unit price.
	 *
	 * @since 0.1.0
	 */
	public function unit_price(): Money {
		return $this->unit_price;
	}

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

	/**
	 * Line total.
	 *
	 * @since 0.1.0
	 */
	public function line_total(): Money {
		return $this->unit_price->multiply( $this->quantity );
	}
}