MessageFolder::decreaseDirCounter

static function decreaseDirCounter($mailboxId, $dirWithMessagesId, $idsUnseenCount)
{
	if($dirWithMessagesId)
	{
		if(MailCounterTable::getCount([
			'=MAILBOX_ID' => $mailboxId,
			'=ENTITY_TYPE' => 'DIR',
			'=ENTITY_ID' => $dirWithMessagesId,
			'>=VALUE' => $idsUnseenCount
		]))
		{
			MailCounterTable::update(
				[
					'MAILBOX_ID' => $mailboxId,
					'ENTITY_TYPE' => 'DIR',
					'ENTITY_ID' => $dirWithMessagesId
				],
				[
					"VALUE" => new BitrixMainDBSqlExpression("?# - $idsUnseenCount", "VALUE")
				]
			);
		}
	}
}