Related posts in WordPress, using few queries

<?
    function ns_get_related_posts($post, $post_type = 'post', $taxonomy = 'tag', $max_posts = null) {
        $terms = get_the_terms($post->ID , $taxonomy);
        $term_ids = array();
        $result = array();

        # If max_posts isn't provided, fall back to global posts_per_page option
        if ($max_posts == null) {
            $max_posts = get_option('posts_per_page');
        }

        # Map array of term ojects to an array of term ID's
        if (!empty($terms)) foreach ($terms as $term) {
            array_push($term_ids, $term->term_id);
        }

        if (!empty($term_ids)) {
            $related_posts = new WP_Query(array(
                'post_type' => $post_type,
                'posts_per_page' => $max_posts,
                'post__not_in' => array($post->ID),
                'tax_query' => array(array(
                    'taxonomy' => $taxonomy,
                    'field' => 'id',
                    'terms' => $term_ids
                ))
            ));

            if($related_posts->have_posts()) {
                foreach ($related_posts->posts as $related_post) {
                    array_push($result, $related_post);
                }
            }
        }

        return $result;
    }