private function buildStatistics($board)
 {
     $board_statistics = $board->getBoardStatistics();
     $statistics = array();
     $statistics['title'] = $board->get_title();
     $statistics['description'] = $board->get_description();
     $statistics['type'] = $board->get_type() . " board";
     $statistics['created_at'] = $board->get_created_at();
     switch ($board->get_type()) {
         case PaForumBoard::network_board:
             $net_id = $board->get_owner_id();
             if ($net_id == 1) {
                 // mother network - owner_id always is '1' !
                 $owner_id = 1;
             } else {
                 $owner_id = Network::get_network_owner((int) $board->get_owner_id());
             }
             break;
         case PaForumBoard::group_board:
             $owner_id = Group::get_owner_id((int) $board->get_owner_id());
             break;
         case PaForumBoard::personal_board:
             $owner_id = $board->get_owner_id();
             break;
     }
     $user = new User();
     $user->load((int) $owner_id);
     $statistics['owner'] = $user;
     $statistics['nb_categories'] = $board_statistics['nb_categories'];
     $nb_forums = 0;
     $nb_threads = 0;
     $nb_posts = 0;
     $threads = array();
     $last_posts = array();
     foreach ($board_statistics['categories'] as $category) {
         if ($category->statistics['nb_forums'] > 0) {
             $nb_forums += $category->statistics['nb_forums'];
             foreach ($category->statistics['forums'] as $forum) {
                 if (!empty($forum->statistics['threads']) and count($forum->statistics['threads']) > 0) {
                     foreach ($forum->statistics['threads'] as &$thr) {
                         $thr->forum = $forum;
                     }
                     $threads = array_merge($threads, $forum->statistics['threads']);
                     $nb_threads += $forum->statistics['nb_threads'];
                     $nb_posts += $forum->statistics['nb_posts'];
                     if (!empty($forum->statistics['last_post'])) {
                         $last_posts[] = $forum->statistics['last_post'];
                     }
                 }
             }
         }
     }
     if (count($threads) > 1) {
         usort($threads, "cmpThreadCreated");
     }
     $statistics['threads'] = $threads;
     $statistics['nb_forums'] = $nb_forums;
     $statistics['nb_threads'] = $nb_threads;
     $statistics['nb_posts'] = $nb_posts;
     $statistics['last_posts'] = $last_posts;
     $statistics['nb_users'] = PaForumsUsers::countPaForumsUsers("board_id = " . $board->get_id());
     return $statistics;
 }