class MetadataBag

class MetadataBag implements SessionBagInterface {
    public const CREATED = 'c';
    public const UPDATED = 'u';
    public const LIFETIME = 'l';
    protected array $meta = [
        self::CREATED => 0,
        self::UPDATED => 0,
        self::LIFETIME => 0,
    ];
    private string $name = '__metadata';
    private int $lastUsed;
    
    /**
     * @param string $storageKey      The key used to store bag in the session
     * @param int    $updateThreshold The time to wait between two UPDATED updates
     */
    public function __construct(string $storageKey = '_sf2_meta', int $updateThreshold = 0) {
    }
    public function initialize(array &$array) : void {
        $this->meta =& $array;
        if (isset($array[self::CREATED])) {
            $this->lastUsed = $this->meta[self::UPDATED];
            $timeStamp = time();
            if ($timeStamp - $array[self::UPDATED] >= $this->updateThreshold) {
                $this->meta[self::UPDATED] = $timeStamp;
            }
        }
        else {
            $this->stampCreated();
        }
    }
    
    /**
     * Gets the lifetime that the session cookie was set with.
     */
    public function getLifetime() : int {
        return $this->meta[self::LIFETIME];
    }
    
    /**
     * Stamps a new session's metadata.
     *
     * @param int|null $lifetime Sets the cookie lifetime for the session cookie. A null value
     *                           will leave the system settings unchanged, 0 sets the cookie
     *                           to expire with browser session. Time is in seconds, and is
     *                           not a Unix timestamp.
     */
    public function stampNew(?int $lifetime = null) : void {
        $this->stampCreated($lifetime);
    }
    public function getStorageKey() : string {
        return $this->storageKey;
    }
    
    /**
     * Gets the created timestamp metadata.
     *
     * @return int Unix timestamp
     */
    public function getCreated() : int {
        return $this->meta[self::CREATED];
    }
    
    /**
     * Gets the last used metadata.
     *
     * @return int Unix timestamp
     */
    public function getLastUsed() : int {
        return $this->lastUsed;
    }
    public function clear() : mixed {
        // nothing to do
        return null;
    }
    public function getName() : string {
        return $this->name;
    }
    
    /**
     * Sets name.
     */
    public function setName(string $name) : void {
        $this->name = $name;
    }
    private function stampCreated(?int $lifetime = null) : void {
        $timeStamp = time();
        $this->meta[self::CREATED] = $this->meta[self::UPDATED] = $this->lastUsed = $timeStamp;
        $this->meta[self::LIFETIME] = $lifetime ?? (int) \ini_get('session.cookie_lifetime');
    }

}