<?php
function custom_search_where($where){

	global $wpdb;

	if (is_search() && get_search_query())
	  $where .= "OR ((t.name LIKE '%".get_search_query()."%' OR t.slug LIKE '%".get_search_query()."%') AND {$wpdb->posts}.post_status = 'publish')";

	// WPML
	if (function_exists('icl_get_languages')) {
		$lang_code = 'it'; // better set a default lang code as fallback here
		if(defined('ICL_LANGUAGE_CODE') && ICL_LANGUAGE_CODE != '') {
			$lang_code = ICL_LANGUAGE_CODE;
		}
		$where .= "AND language_code = '".$lang_code."'";
	}

	return $where;
  }
  
  function custom_search_join($join){

	global $wpdb;
	if (is_search()&& get_search_query())
	  $join .= "LEFT JOIN {$wpdb->term_relationships} tr ON {$wpdb->posts}.ID = tr.object_id INNER JOIN {$wpdb->term_taxonomy} tt ON tt.term_taxonomy_id=tr.term_taxonomy_id INNER JOIN {$wpdb->terms} t ON t.term_id = tt.term_id";

	return $join;
  }
  
  function custom_search_groupby($groupby){

	//if(is_admin()) return;

	global $wpdb;
  
	// we need to group on post ID
	$groupby_id = "{$wpdb->posts}.ID";
	if(!is_search() || strpos($groupby, $groupby_id) !== false || !get_search_query()) return $groupby;
  
	// groupby was empty, use ours
	if(!strlen(trim($groupby))) return $groupby_id;
 
	// wasn't empty, append ours
	return $groupby.", ".$groupby_id;
  }
  
if(!is_admin()) {
	add_filter('posts_where','custom_search_where');
	add_filter('posts_join', 'custom_search_join');
	add_filter('posts_groupby', 'custom_search_groupby');
}

?>