Message::getFileIdsFromActivities

protected function getFileIdsFromActivities(int $messageId): array
{
	$activities = $this->getActivities(
		[
			'ID' => $messageId,
		],
		self::SUPPORTED_ACTIVITY_TYPE,
		[
			'STORAGE_ELEMENT_IDS',
		]
	);

	if (!$this->checkActivityPermission(self::PERMISSION_READ, $activities))
	{
		return [];
	}

	if ($activities[0])
	{
		$activity = $activities[0];

		$filesIDs = array_unique($activity['STORAGE_ELEMENT_IDS'], SORT_NUMERIC);

		$activityBFileIds = [];

		foreach ($filesIDs as $fileID)
		{
			$file = File::loadById($fileID);
			if ($file)
			{
				$activityBFileIds[] = (int)$file->getFileId();
			}
		}

		return $activityBFileIds;
	}

	return [];
}