daily link click limit

add_filter( 'mycred_add', 'daily_link_click_limit', 10, 3 );
function daily_link_click_limit( $reply, $request, $mycred )
{
    if ( $request['ref'] != 'link_click' || $reply === false ) return $reply;

    $max_per_day = 25;
    $user_id = absint( $request['user_id'] );

    global $wpdb;
    $count = $wpdb->get_var( $wpdb->prepare( "
        SELECT COUNT( * )
        FROM {$mycred->log_table}
        WHERE ref = %s
            AND user_id = %d
            AND time > %d;", 'link_click', $user_id, date_i18n( 'U', strtotime( 'today midnight' ) ) ) );

    if ( $count >= $max_per_day )
        return false;

    return $reply;
}