class MongoDbSessionHandler

class MongoDbSessionHandler extends AbstractSessionHandler {
    private Manager $manager;
    private string $namespace;
    private array $options;
    private int|\Closure|null $ttl;
    
    /**
     * Constructor.
     *
     * List of available options:
     *  * database: The name of the database [required]
     *  * collection: The name of the collection [required]
     *  * id_field: The field name for storing the session id [default: _id]
     *  * data_field: The field name for storing the session data [default: data]
     *  * time_field: The field name for storing the timestamp [default: time]
     *  * expiry_field: The field name for storing the expiry-timestamp [default: expires_at]
     *  * ttl: The time to live in seconds.
     *
     * It is strongly recommended to put an index on the `expiry_field` for
     * garbage-collection. Alternatively it's possible to automatically expire
     * the sessions in the database as described below:
     *
     * A TTL collections can be used on MongoDB 2.2+ to cleanup expired sessions
     * automatically. Such an index can for example look like this:
     *
     *     db.<session-collection>.createIndex(
     *         { "<expiry-field>": 1 },
     *         { "expireAfterSeconds": 0 }
     *     )
     *
     * More details on: https://docs.mongodb.org/manual/tutorial/expire-data/
     *
     * If you use such an index, you can drop `gc_probability` to 0 since
     * no garbage-collection is required.
     *
     * @throws \InvalidArgumentException When "database" or "collection" not provided
     */
    public function __construct(Client|Manager $mongo, array $options) {
        if (!isset($options['database']) || !isset($options['collection'])) {
            throw new \InvalidArgumentException('You must provide the "database" and "collection" option for MongoDBSessionHandler.');
        }
        if ($mongo instanceof Client) {
            $mongo = $mongo->getManager();
        }
        $this->manager = $mongo;
        $this->namespace = $options['database'] . '.' . $options['collection'];
        $this->options = array_merge([
            'id_field' => '_id',
            'data_field' => 'data',
            'time_field' => 'time',
            'expiry_field' => 'expires_at',
        ], $options);
        $this->ttl = $this->options['ttl'] ?? null;
    }
    public function close() : bool {
        return true;
    }
    protected function doDestroy(string $sessionId) : bool {
        $write = new BulkWrite();
        $write->delete([
            $this->options['id_field'] => $sessionId,
        ], [
            'limit' => 1,
        ]);
        $this->manager
            ->executeBulkWrite($this->namespace, $write);
        return true;
    }
    public function gc(int $maxlifetime) : int|false {
        $write = new BulkWrite();
        $write->delete([
            $this->options['expiry_field'] => [
                '$lt' => $this->getUTCDateTime(),
            ],
        ]);
        $result = $this->manager
            ->executeBulkWrite($this->namespace, $write);
        return $result->getDeletedCount() ?? false;
    }
    protected function doWrite(string $sessionId, string $data) : bool {
        $ttl = ($this->ttl instanceof \Closure ? ($this->ttl)() : $this->ttl) ?? \ini_get('session.gc_maxlifetime');
        $expiry = $this->getUTCDateTime($ttl);
        $fields = [
            $this->options['time_field'] => $this->getUTCDateTime(),
            $this->options['expiry_field'] => $expiry,
            $this->options['data_field'] => new Binary($data, Binary::TYPE_GENERIC),
        ];
        $write = new BulkWrite();
        $write->update([
            $this->options['id_field'] => $sessionId,
        ], [
            '$set' => $fields,
        ], [
            'upsert' => true,
        ]);
        $this->manager
            ->executeBulkWrite($this->namespace, $write);
        return true;
    }
    public function updateTimestamp(string $sessionId, string $data) : bool {
        $ttl = ($this->ttl instanceof \Closure ? ($this->ttl)() : $this->ttl) ?? \ini_get('session.gc_maxlifetime');
        $expiry = $this->getUTCDateTime($ttl);
        $write = new BulkWrite();
        $write->update([
            $this->options['id_field'] => $sessionId,
        ], [
            '$set' => [
                $this->options['time_field'] => $this->getUTCDateTime(),
                $this->options['expiry_field'] => $expiry,
            ],
        ], [
            'multi' => false,
        ]);
        $this->manager
            ->executeBulkWrite($this->namespace, $write);
        return true;
    }
    protected function doRead(string $sessionId) : string {
        $cursor = $this->manager
            ->executeQuery($this->namespace, new Query([
            $this->options['id_field'] => $sessionId,
            $this->options['expiry_field'] => [
                '$gte' => $this->getUTCDateTime(),
            ],
        ], [
            'projection' => [
                '_id' => false,
                $this->options['data_field'] => true,
            ],
            'limit' => 1,
        ]));
        foreach ($cursor as $document) {
            return (string) $document->{$this->options['data_field']} ?? '';
        }
        // Not found
        return '';
    }
    private function getUTCDateTime(int $additionalSeconds = 0) : UTCDateTime {
        return new UTCDateTime((time() + $additionalSeconds) * 1000);
    }

}