ViewedService::getLastViewedMessageId

public function getLastViewedMessageId(int $chatId): ?int
{
	$result = MessageViewedTable::query()
		->setSelect(['LAST_VIEWED' => new ExpressionField('LAST_VIEWED', 'MAX(%s)', ['MESSAGE_ID'])])
		->where('CHAT_ID', $chatId)
		->where('USER_ID', $this->getContext()->getUserId())
		->fetch()
	;

	return ($result && isset($result['LAST_VIEWED'])) ? (int)$result['LAST_VIEWED'] : null;
}