[Forminator Pro] - Rename the uploaded file name based on a text field

forminator-rename-uploaded-filename.php

<?php
/**
 * Plugin Name: [Forminator Pro] Rename the uploaded file name.
 * Description: Rename the file uploaded based on the text field in a multiupload field.
 * Author: Prashant @ WPMUDEV
 * Task: SLS-6496
 * Author URI: https://premium.wpmudev.org
 * License: GPLv2 or later
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly.
}

function wpmudev_modify_uploaded_file_name( $filename ) {
	$prefix   = Forminator_CForm_Front_Action::$prepared_data['text-1'];
	$filename = ! empty( $prefix ) ? $prefix . '-' . $filename : $filename;
	return $filename;
}

add_action( 'forminator_form_before_handle_submit', 'wpmudev_uploaded_filename_fix', 10, 1 );
add_action( 'forminator_form_before_save_entry', 'wpmudev_uploaded_filename_fix', 10, 1 );
function wpmudev_uploaded_filename_fix( $form_id ) {
	if ( 2960 !== intval( $form_id ) ) { // Please change the form ID.
		return;
	}

	add_filter( 'wp_unique_filename', 'wpmudev_modify_uploaded_file_name', 10, 1 );
}