host = DB_HOST;
        $this->user = DB_USER;
        $this->pass = DB_PASS;
        $this->dbname = DB_NAME;
        $this->connect();
    }

    /**
     * Get singleton instance
     */
    public static function getInstance() {
        if (!self::$instance) {
            self::$instance = new Database();
        }
        return self::$instance;
    }

    /**
     * Connect to the database
     */
    private function connect() {
        try {
            $this->conn = new PDO(
                "mysql:host={$this->host};dbname={$this->dbname}",
                $this->user,
                $this->pass,
                array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8'")
            );
            $this->conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            $this->conn->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
        } catch (PDOException $e) {
            die("Database Connection Error: " . $e->getMessage());
        }
    }

    /**
     * Get database connection
     */
    public function getConnection() {
        return $this->conn;
    }

    /**
     * Execute a query with optional parameters
     */
    public function query($sql, $params = []) {
        try {
            $stmt = $this->conn->prepare($sql);
            $stmt->execute($params);
            return $stmt;
        } catch (PDOException $e) {
            die("Query Error: " . $e->getMessage());
        }
    }

    /**
     * Get a single record
     */
    public function single($sql, $params = []) {
        $stmt = $this->query($sql, $params);
        return $stmt->fetch();
    }

    /**
     * Get multiple records
     */
    public function resultSet($sql, $params = []) {
        $stmt = $this->query($sql, $params);
        return $stmt->fetchAll();
    }

    /**
     * Get row count
     */
    public function rowCount($sql, $params = []) {
        $stmt = $this->query($sql, $params);
        return $stmt->rowCount();
    }

    /**
     * Get last inserted ID
     */
    public function lastInsertId() {
        return $this->conn->lastInsertId();
    }
}