+ $blocked = explode(',', $blocked_txt);
+ array_walk($blocked, function(&$value) { $value = "'" . DBA::escape(trim($value)) . "'";});
+ return " AND NOT `name` IN (" . implode(',', $blocked) . ")";
+ }
+
+ /**
+ * Creates a list of the most frequent global hashtags over the given period
+ *
+ * @param int $period Period in hours to consider posts
+ * @param int $limit Number of returned tags
+ * @return array
+ * @throws \Exception
+ */
+ public static function setGlobalTrendingHashtags(int $period, int $limit = 10)
+ {
+ // Get a uri-id that is at least X hours old.
+ // We use the uri-id in the query for the hash tags since this is much faster
+ $post = Post::selectFirstThread(['uri-id'], ["`uid` = ? AND `received` < ?", 0, DateTimeFormat::utc('now - ' . $period . ' hour')],
+ ['order' => ['received' => true]]);
+ if (empty($post['uri-id'])) {
+ return [];
+ }
+
+ $block_sql = self::getBlockedSQL();
+
+ $tagsStmt = DBA::p("SELECT `name` AS `term`, COUNT(*) AS `score`, COUNT(DISTINCT(`author-id`)) as `authors`
+ FROM `tag-search-view`
+ WHERE `private` = ? AND `uid` = ? AND `uri-id` > ? $block_sql
+ GROUP BY `term` ORDER BY `authors` DESC, `score` DESC LIMIT ?",
+ Item::PUBLIC, 0, $post['uri-id'], $limit);
+
+ if (DBA::isResult($tagsStmt)) {
+ $tags = DBA::toArray($tagsStmt);
+ DI::cache()->set('global_trending_tags-' . $period . '-' . $limit, $tags, Duration::DAY);
+ return $tags;
+ }
+
+ return [];