Resolve "Backend code update"

Closes #4 (closed)

lib/SessionStatistics.php

-<?php
-
-declare(strict_types=1);
-
-/**
- * SPDX-FileCopyrightText: 2016 Nextcloud GmbH and Nextcloud contributors
- * SPDX-License-Identifier: AGPL-3.0-or-later
- */
-
-namespace OCA\SccuotNC;
-
-use OCP\AppFramework\Utility\ITimeFactory;
-use OCP\IDBConnection;
-
-/**
- * Class SessionStatistics
- *
- * get active users
- *
- * @group DB
- * @package OCA\ServerInfo
- */
-class SessionStatistics {
-	private const OFFSET_5MIN = 300;
-	private const OFFSET_1HOUR = 3600;
-	private const OFFSET_1DAY = 86400;
-	private const OFFSET_7DAYS = 604800;
-	private const OFFSET_1MONTH = 2592000;
-	private const OFFSET_3MONTHS = 7776000;
-	private const OFFSET_6MONTHS = 15552000;
-	private const OFFSET_1YEAR = 31536000;
-
-	private IDBConnection $connection;
-	private ITimeFactory $timeFactory;
-
-	public function __construct(IDBConnection $connection, ITimeFactory $timeFactory) {
-		$this->connection = $connection;
-		$this->timeFactory = $timeFactory;
-	}
-
-	public function getSessionStatistics(): array {
-		return [
-			'last5minutes' => $this->getNumberOfActiveUsers(self::OFFSET_5MIN),
-			'last1hour' => $this->getNumberOfActiveUsers(self::OFFSET_1HOUR),
-			'last24hours' => $this->getNumberOfActiveUsers(self::OFFSET_1DAY),
-			'last7days' => $this->getNumberOfActiveUsers(self::OFFSET_7DAYS),
-			'last1month' => $this->getNumberOfActiveUsers(self::OFFSET_1MONTH),
-			'last3months' => $this->getNumberOfActiveUsers(self::OFFSET_3MONTHS),
-			'last6months' => $this->getNumberOfActiveUsers(self::OFFSET_6MONTHS),
-			'lastyear' => $this->getNumberOfActiveUsers(self::OFFSET_1YEAR),
-		];
-	}
-
-	/**
-	 * get number of active user in a given time span
-	 *
-	 * @param int $offset seconds
-	 */
-	private function getNumberOfActiveUsers(int $offset): int {
-		$query = $this->connection->getQueryBuilder();
-		$query->select('uid')
-			->from('authtoken')
-			->where($query->expr()->gte(
-				'last_activity',
-				$query->createNamedParameter($this->timeFactory->getTime() - $offset)
-			))->groupBy('uid');
-
-		$result = $query->executeQuery();
-		$activeUsers = $result->fetchAll();
-		$result->closeCursor();
-
-		return count($activeUsers);
-	}
-}