function acl_autocomplete()
    {
        $this->load_config();

        $search = rcube_utils::get_input_value('_search', rcube_utils::INPUT_GPC, true);
        $reqid  = rcube_utils::get_input_value('_reqid', rcube_utils::INPUT_GPC);
        $users  = array();
        $keys   = array();

        if ($this->init_ldap()) {
            $max  = (int) $this->rc->config->get('autocomplete_max', 15);
            $mode = (int) $this->rc->config->get('addressbook_search_mode');

            $this->ldap->set_pagesize($max);
            $result = $this->ldap->search('*', $search, $mode);

            foreach ($result->records as $record) {
                $user = $record['uid'];

                if (is_array($user)) {
                    $user = array_filter($user);
                    $user = $user[0];
                }

                if ($user) {
                    $display = rcube_addressbook::compose_search_name($record);
                    $user    = array('name' => $user, 'display' => $display);
                    $users[] = $user;
                    $keys[]  = $display ?: $user['name'];
                }
            }

            if ($this->rc->config->get('acl_groups')) {
                $prefix      = $this->rc->config->get('acl_group_prefix');
                $group_field = $this->rc->config->get('acl_group_field', 'name');
                $result      = $this->ldap->list_groups($search, $mode);

                foreach ($result as $record) {
                    $group    = $record['name'];
                    $group_id = is_array($record[$group_field]) ? $record[$group_field][0] : $record[$group_field];

                    if ($group) {
                        $users[] = array('name' => ($prefix ?: '') . $group_id, 'display' => $group, 'type' => 'group');
                        $keys[]  = $group;
                    }
                }
            }
        }

        if (count($users)) {
            // sort users index
            asort($keys, SORT_LOCALE_STRING);
            // re-sort users according to index
            foreach ($keys as $idx => $val) {
                $keys[$idx] = $users[$idx];
            }
            $users = array_values($keys);
        }

        $this->rc->output->command('ksearch_query_results', $users, $search, $reqid);
        $this->rc->output->send();
    }