<?php
declare(strict_types=1);

class DbSessionHandler implements SessionHandlerInterface
{
    private const TTL = 86400 * 30; // 30 days

    public function open($path, $name): bool { return true; }
    public function close(): bool { return true; }

    public function read($id): string
    {
        $stmt = db()->prepare("SELECT data FROM sessions WHERE id = ? AND updated_at > DATE_SUB(NOW(), INTERVAL " . self::TTL . " SECOND)");
        $stmt->execute([$id]);
        $row = $stmt->fetch();
        return $row ? $row['data'] : '';
    }

    public function write($id, $data): bool
    {
        db()->prepare("INSERT INTO sessions (id, data) VALUES (?, ?) ON DUPLICATE KEY UPDATE data = VALUES(data), updated_at = NOW()")
            ->execute([$id, $data]);
        return true;
    }

    public function destroy($id): bool
    {
        db()->prepare("DELETE FROM sessions WHERE id = ?")->execute([$id]);
        return true;
    }

    public function gc($max_lifetime): int
    {
        $stmt = db()->prepare("DELETE FROM sessions WHERE updated_at < DATE_SUB(NOW(), INTERVAL ? SECOND)");
        $stmt->execute([self::TTL]);
        return (int)$stmt->rowCount();
    }
}