Dynamically add Bootstrap column classes to footer widgets, depending on how many widgets are present

custom.php

<?php

// Dynamically add Bootstrap column classes to footer widgets, depending on how many widgets are present
add_filter('dynamic_sidebar_params','tibs_footer_sidebar_params'); 
function tibs_footer_sidebar_params($params) {

    $sidebar_id = $params[0]['id'];

    if ( $sidebar_id == 'sidebar-footer' ) {

        $total_widgets = wp_get_sidebars_widgets();
        $sidebar_widgets = count($total_widgets[$sidebar_id]);

        $params[0]['before_widget'] = str_replace('<section class="widget ', '<section class="widget col-md-' . floor(12 / $sidebar_widgets) . ' ', $params[0]['before_widget']);
    }

    return $params;
}