public function process_refund( $order_id, $amount = null, $reason = '' ) {
		$order = wc_get_order( $order_id );

		if ( ! $this->can_refund_order( $order ) ) {
			return new WP_Error( 'error', __( 'Refund failed.', 'woocommerce' ) );
		}

		$this->init_api();

		$result = WC_Gateway_Paypal_API_Handler::refund_transaction( $order, $amount, $reason );

		if ( is_wp_error( $result ) ) {
			$this->log( 'Refund Failed: ' . $result->get_error_message(), 'error' );
			return new WP_Error( 'error', $result->get_error_message() );
		}

		$this->log( 'Refund Result: ' . wc_print_r( $result, true ) );

		switch ( strtolower( $result->ACK ) ) { // phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
			case 'success':
			case 'successwithwarning':
				$order->add_order_note(
					/* translators: 1: Refund amount, 2: Refund ID */
					sprintf( __( 'Refunded %1$s - Refund ID: %2$s', 'woocommerce' ), $result->GROSSREFUNDAMT, $result->REFUNDTRANSACTIONID ) // phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
				);
				return true;
		}

		return isset( $result->L_LONGMESSAGE0 ) ? new WP_Error( 'error', $result->L_LONGMESSAGE0 ) : false; // phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
	}