<?php
declare(strict_types=1);

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

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

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

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

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