Comment::processMentions

static function processMentions(array $fields): array
{
	$newMentionedUserIds = [];

	if (
		TaskLimit::isLimitExceeded()
		|| !is_array($fields)
		|| !isset($fields['MESSAGE']['POST_MESSAGE'], $fields['PARAMS']['AUX'])
		|| ($fields['PARAMS']['AUX'] === 'Y' && $fields['PARAMS']['IS_PING_COMMENT'] !== 'Y')
	)
	{
		return $newMentionedUserIds;
	}

	preg_match_all(
		"/[users*=s*([^]]*)](.+?)[/user]/is" . BX_UTF_PCRE_MODIFIER,
		$fields['MESSAGE']['POST_MESSAGE'],
		$matches
	);

	if (!is_array($matches) || empty($matches) || !is_array($matches[1]) || empty($matches[1]))
	{
		return $newMentionedUserIds;
	}

	$mentionedUserIds = array_filter(array_map('intval', $matches[1]));
	if (empty($mentionedUserIds))
	{
		return $newMentionedUserIds;
	}

	$task = false;
	$taskData = false;
	$taskMembers = [];

	if (isset($fields['PARAMS']['XML_ID']))
	{
		preg_match("/TASK_(d+)/is" . BX_UTF_PCRE_MODIFIER, $fields['PARAMS']['XML_ID'], $matches);
		if (is_array($matches) && !empty($matches[1]) && (int)$matches[1])
		{
			try
			{
				$task = new CTaskItem((int)$matches[1], User::getId());
				$taskData = $task->getData();
				$taskMembers = CTaskNotifications::getRecipientsIDs($taskData, false);
			}
			catch (TasksException | CTaskAssertException $e)
			{

			}
		}
	}

	if (!empty($taskMembers))
	{
		foreach ($mentionedUserIds as $userId)
		{
			if (!in_array($userId, $taskMembers))
			{
				$newMentionedUserIds[] = (int)$userId;
			}
		}
	}

	if ($task && $taskData)
	{
		if (!empty($newMentionedUserIds))
		{
			static::addNewAuditorsFromMentions($task, $newMentionedUserIds);
			static::sendUpdateNotificationToOldMembers($taskData, $newMentionedUserIds);
		}
		static::unmuteMentionedUsers($task, $mentionedUserIds);
	}

	return $newMentionedUserIds;
}