public static function grant_access_to_download() {

		check_ajax_referer( 'grant-access', 'security' );

		if ( ! current_user_can( 'edit_shop_orders' ) || ! isset( $_POST['loop'], $_POST['order_id'], $_POST['product_ids'] ) ) {
			wp_die( -1 );
		}

		global $wpdb;

		$wpdb->hide_errors();

		$order_id     = intval( $_POST['order_id'] );
		$product_ids  = array_filter( array_map( 'absint', (array) wp_unslash( $_POST['product_ids'] ) ) );
		$loop         = intval( $_POST['loop'] );
		$file_counter = 0;
		$order        = wc_get_order( $order_id );

		foreach ( $product_ids as $product_id ) {
			$product = wc_get_product( $product_id );
			$files   = $product->get_downloads();

			if ( ! $order->get_billing_email() ) {
				wp_die();
			}

			if ( ! empty( $files ) ) {
				foreach ( $files as $download_id => $file ) {
					$inserted_id = wc_downloadable_file_permission( $download_id, $product_id, $order );
					if ( $inserted_id ) {
						$download = new WC_Customer_Download( $inserted_id );
						$loop ++;
						$file_counter ++;

						if ( $file->get_name() ) {
							$file_count = $file->get_name();
						} else {
							/* translators: %d file count */
							$file_count = sprintf( __( 'File %d', 'woocommerce' ), $file_counter );
						}
						include 'admin/meta-boxes/views/html-order-download-permission.php';
					}
				}
			}
		}
		wp_die();
	}