Automatically set event categories as post categories for The Events Calendar

/**
 * Automatically set event categories as post categories for the Events Calendar.
 */
function set_event_categories_as_post_categories( $post_id ) {
    // Check if the post is an event post type
    if ( 'tribe_events' === get_post_type( $post_id ) ) {
        // Get the event categories
        $event_categories = wp_get_post_terms( $post_id, 'tribe_events_cat', array( 'fields' => 'names' ) );

        // Set event categories as post categories
        $post_categories = array();
        foreach ( $event_categories as $event_category_name ) {
            // Check if the category exists, and if not, create it
            $existing_category = get_category_by_slug( sanitize_title( $event_category_name ) );

            if ( ! $existing_category ) {
                $category_args = array(
                    'cat_name' => $event_category_name,
                    'category_nicename' => sanitize_title( $event_category_name ),
                );
                $existing_category = wp_insert_category( $category_args );
            }

            // Add the category ID to the post categories
            if ( $existing_category ) {
                $post_categories[] = $existing_category->term_id;
            }
        }

        // Set the post categories
        wp_set_post_categories( $post_id, $post_categories );
    }
}
add_action( 'save_post', 'set_event_categories_as_post_categories' );