$customer_id->get_error_message() ),
					400
				);
			}

			// Associate customer with the order.
			$order->set_customer_id( $customer_id );

			// Set the customer auth cookie.
			wc_set_customer_auth_cookie( $customer_id );
			wc_log_order_step( '[Store API #6::process_customer] Created new customer', array( 'customer_id' => $customer_id ) );
		}

		// Persist customer address data to account.
		$this->order_controller->sync_customer_data_with_order( $order );
		wc_log_order_step( '[Store API #6::process_customer] Synced customer data from order', array( 'customer_id' => $order->get_customer_id() ) );
	}

	/**
	 * Check request options and store (shop) config to determine if a user account should be created as part of order
	 * processing.
	 *
	 * @param \WP_REST_Request $request The current request object being handled.
	 * @return boolean True if a new user account should be created.
	 */
	private function should_create_customer_account( \WP_REST_Request $request ) {
		if ( is_user_logged_in() ) {
			return false;
		}

		// Return false if registration is not enabled for the store.
		if ( false === filter_var( WC()->checkout()->is_registration_enabled(), FILTER_VALIDATE_BOOLEAN ) ) {
			return false;
		}

		// Return true if the store requires an account for all purchases. Note - checkbox is not displayed to shopper in this case.
		if ( true === filter_var( WC()->checkout()->is_registration_required(), FILTER_VALIDATE_BOOLEAN ) ) {
			return true;
		}

		// Create an account if requested via the endpoint.
		if ( true === filter_var( $request['create_account'], FILTER_VALIDATE_BOOLEAN ) ) {
			// User has requested an account as part of checkout processing.
			return true;
		}

		return false;
	}

	/**
	 * Reject the order if what the customer is going to be charged at is higher from what they saw.
	 *
	 * Runs on POST /checkout only, before the draft order is materialised, so a mismatch leaves
	 * no order behind. The check only runs when the client sends the total it displayed; flows
	 * that cannot know the final total up front (e.g. some express payment methods) omit it and
	 * are unaffected.
	 *
	 * @phpstan-param \WP_REST_Request<array<string, mixed>> $request
	 *
	 * @param \WP_REST_Request $request Request object.
	 * @throws RouteException When the recalculated total is higher. Returns HTTP 409 with the refreshed cart so the client can display the updated total.
	 */
	private function validate_order_totals( \WP_REST_Request $request ): void {
		// The route schema constrains this to minor-unit digits, so the integer comparison below is exact.
		$expected_total = (string) ( $request['expected_total'] ?? '' );

		if ( '' === $expected_total ) {
			return;
		}

		// CartSchema::prepare_money_response() is not exported, so we use the money formatter directly here to match the total_price format.
		$decimals     = wc_get_price_decimals();
		$actual_total = woocommerce_store_api_get_formatter( 'money' )->format(
			$this->cart_controller->get_cart_instance()->get_total( 'edit' ),
			[ 'decimals' => $decimals ]
		);

		if ( (int) $actual_total <= (int) $expected_total ) {
			return;
		}

		$expected_amount = wc_remove_number_precision( absint( $expected_total ) );
		$actual_amount   = wc_remove_number_precision( absint( $actual_total ) );

		throw new RouteException(
			'woocommerce_rest_checkout_total_mismatch',
			sprintf(
				/* translators: %1$s: total the shopper confirmed, %2$s: updated, higher total */
				esc_html__( 'The order total changed from %1$s to %2$s while you were checking out. Please review the updated total and place your order again.', 'woocommerce' ),
				esc_html( wc_price( $expected_amount, [ 'in_span' => false ] ) ),
				esc_html( wc_price( $actual_amount, [ 'in_span' => false ] ) )
			),
			409,
			[
				'expected_total' => absint( $expected_total ),
				'actual_total'   => absint( $actual_total ),
			]
		);
	}

	/**
	 * This validates if the order can be placed regarding settings in WooCommerce > Settings > Accounts & Privacy
	 * If registration during checkout is disabled, guest checkout is disabled and the user is not logged in, prevent checkout.
	 *
	 * @throws RouteException If user cannot place order.
	 */
	private function validate_user_can_place_order() {
		if (
			// "woocommerce_enable_signup_and_login_from_checkout" === no.
			false === filter_var( WC()->checkout()->is_registration_enabled(), FILTER_VALIDATE_BOOLEAN ) &&
			// "woocommerce_enable_guest_checkout" === no.
			true === filter_var( WC()->checkout()->is_registration_required(), FILTER_VALIDATE_BOOLEAN ) &&
			! is_user_logged_in()
		) {
			throw new RouteException(
				'woocommerce_rest_guest_checkout_disabled',
				esc_html(
					/**
					 * Filter to customize the checkout message when a user must be logged in.
					 *
					 * @since 9.4.3
					 *
					 * @param string $message Message to display when a user must be logged in to check out.
					 */
					apply_filters(
						'woocommerce_checkout_must_be_logged_in_message',
						__( 'You must be logged in to checkout.', 'woocommerce' )
					)
				),
				403
			);
		}
	}
}