FacetWP – treat number range like “max capacity”

<?php

function fwp_max_capacity( $return, $params ) {
    $facet_name = $params['facet']['name'];

    if ( 'max_capacity' == $facet_name ) {
        $values = $params['selected_values'];
        $max_capacity = ( '' == $values[0] ) ? false : $values[0];

        global $wpdb;

        if ( false !== $max_capacity ) {
            $where .= " AND (facet_value + 0) >= '$max_capacity'";
        }

        $sql = "
        SELECT DISTINCT post_id FROM {$wpdb->prefix}facetwp_index
        WHERE facet_name = '$facet_name' $where";
        return $wpdb->get_col( $sql );
    }
    return $return;
}
add_filter( 'facetwp_facet_filter_posts', 'fwp_max_capacity', 10, 2 );