<?php
/**
 * Server-side validation for the Checkout block.
 *
 * @package Extrova
 */

declare( strict_types=1 );

namespace Extrova\StoreApi;

use Extrova\Core\ContextFactory;
use Extrova\Core\ExtraService;

defined( 'ABSPATH' ) || exit;

/**
 * Adds extra validation errors to `woocommerce_store_api_cart_errors`, which makes WooCommerce
 * refuse the order. Errors are only added while processing `POST /wc/store/v1/checkout`
 * (including express payments); in regular cart responses they travel as
 * `extensions['extrova'].errors` so the block shows them inline without
 * flagging the whole cart as invalid.
 *
 * @since 1.0.0
 */
final class CartValidation {

	/**
	 * Whether the current REST request is a checkout submission.
	 *
	 * @var bool
	 */
	private bool $is_checkout_request = false;

	/**
	 * Constructor.
	 *
	 * @param ExtraService   $service  Engine.
	 * @param ContextFactory $contexts Contexts.
	 */
	public function __construct(
		private ExtraService $service,
		private ContextFactory $contexts
	) {}

	/**
	 * Tracks the REST request (`rest_request_before_callbacks`).
	 *
	 * @param mixed $response Response (unchanged).
	 * @param mixed $handler  Handler.
	 * @param mixed $request  Request.
	 * @return mixed
	 */
	public function track_request( mixed $response, mixed $handler, mixed $request ): mixed {
		if ( $request instanceof \WP_REST_Request ) {
			$this->is_checkout_request = 'POST' === $request->get_method()
				&& 1 === preg_match( '#^/wc/store(?:/v\d+)?/checkout/?$#', (string) $request->get_route() );
		}
		return $response;
	}

	/**
	 * Adds errors on checkout submission.
	 *
	 * @param \WP_Error $errors Errors.
	 * @param \WC_Cart  $cart   Cart.
	 */
	public function validate( \WP_Error $errors, \WC_Cart $cart ): void {
		if ( ! $this->is_checkout_request ) {
			return;
		}
		$result = $this->service->validate_all( $this->contexts->from_cart( $cart, 'checkout_block' ) );
		if ( $result->has_errors() ) {
			$errors->merge_from( $result );
		}
	}
}