public function check_response() {
		if ( empty( $_REQUEST['cm'] ) || empty( $_REQUEST['tx'] ) || empty( $_REQUEST['st'] ) ) { // WPCS: Input var ok, CSRF ok, sanitization ok.
			return;
		}

		$order_id    = wc_clean( wp_unslash( $_REQUEST['cm'] ) ); // WPCS: input var ok, CSRF ok, sanitization ok.
		$status      = wc_clean( strtolower( wp_unslash( $_REQUEST['st'] ) ) ); // WPCS: input var ok, CSRF ok, sanitization ok.
		$amount      = isset( $_REQUEST['amt'] ) ? wc_clean( wp_unslash( $_REQUEST['amt'] ) ) : 0; // WPCS: input var ok, CSRF ok, sanitization ok.
		$transaction = wc_clean( wp_unslash( $_REQUEST['tx'] ) ); // WPCS: input var ok, CSRF ok, sanitization ok.
		$order       = $this->get_paypal_order( $order_id );

		if ( ! $order || ! $order->needs_payment() ) {
			return false;
		}

		$transaction_result = $this->validate_transaction( $transaction );

		if ( $transaction_result ) {
			WC_Gateway_Paypal::log( 'PDT Transaction Status: ' . wc_print_r( $status, true ) );

			$order->add_meta_data( '_paypal_status', $status );
			$order->set_transaction_id( $transaction );

			if ( 'completed' === $status ) {
				if ( number_format( $order->get_total(), 2, '.', '' ) !== number_format( $amount, 2, '.', '' ) ) {
					WC_Gateway_Paypal::log( 'Payment error: Amounts do not match (amt ' . $amount . ')', 'error' );
					/* translators: 1: Payment amount */
					$this->payment_on_hold( $order, sprintf( __( 'Validation error: PayPal amounts do not match (amt %s).', 'woocommerce' ), $amount ) );
				} else {
					// Log paypal transaction fee and payment type.
					if ( ! empty( $transaction_result['mc_fee'] ) ) {
						$order->add_meta_data( 'PayPal Transaction Fee', wc_clean( $transaction_result['mc_fee'] ) );
					}
					if ( ! empty( $transaction_result['payment_type'] ) ) {
						$order->add_meta_data( 'Payment type', wc_clean( $transaction_result['payment_type'] ) );
					}

					$this->payment_complete( $order, $transaction, __( 'PDT payment completed', 'woocommerce' ) );
				}
			} else {
				if ( 'authorization' === $transaction_result['pending_reason'] ) {
					$this->payment_on_hold( $order, __( 'Payment authorized. Change payment status to processing or complete to capture funds.', 'woocommerce' ) );
				} else {
					/* translators: 1: Pending reason */
					$this->payment_on_hold( $order, sprintf( __( 'Payment pending (%s).', 'woocommerce' ), $transaction_result['pending_reason'] ) );
				}
			}
		} else {
			WC_Gateway_Paypal::log( 'Received invalid response from PayPal PDT' );
		}
	}