รบกวนช่วยดู code Login แบบมี level user โดยใช้ OOP PHP PDO แบบไม่ต้องเลือก select option ทีนะครับ

<?php 

    session_start();
    include_once('php-plugins/class_admin.php');
    $admin = new Admin();
    if(isset($_POST['btn_login']))
    {
        $user = trim(strip_tags($_POST['log_user']));
        $pass = trim(strip_tags($_POST['log_pass']));
        //$level = trim(strip_tags($_POST['log_level']));
        if($admin->login($user, $pass)) // ไม่ต้องเช็ค level
        {
            $_SESSION['m_id'] = $user;
            //$_SESSION['m_level'] = $level; // ย้ายไป class Admin
            header('location:it-management/index.php');
        }
        else
        {
            $msg = '
            <div class="alert alert-warning alert-dismissible fade show text-center" role="alert"> 
                <strong>Error!</strong> : Username or Password.
                <button type="button" class="close" data-dismiss="alert" aria-label="Close">
                <i class="ik ik-x"></i>
                </button>
            </div>';
        }
    }
    if(isset($_GET['logout']))
    {
        session_destroy();
        header('location:index.php');
    }
    if(!$admin->cekSession())
    {

?>

<?php 
class Admin
{
	private $db;
	public function __construct()
	{
		try 
		{
			$conn = new PDO('mysql:host=localhost;dbname=itmaster_db', 'root', '');
			$this->db = $conn;
		}
		catch(PDOException $e)
		{
			print $e->getMessage();
			die();
		}
	}
	public function login($user, $pass)
	{
		// ตัด level ออกจาก query
		$select_stmt = $this->db->prepare("SELECT * FROM tbl_usermaster WHERE m_username = :user");
		$select_stmt->bindParam(':user', $user);
		//$select_stmt->bindParam(':level', $level); // ไม่ต้อง bind
		try
		{
			$select_stmt->execute();
			if($select_stmt->rowCount() > 0)
			{
				$row = $select_stmt->fetch(PDO::FETCH_ASSOC);
				$hashed = $row['m_password'];
				if( crypt($pass, $hashed) == $hashed )
				{
					$_SESSION['m_level'] = $row['m_level']; // ย้ายมาไว้ตรงนี้
					return true;
				}
				else
				{
					return false;
				}
			}
			else
			{
				return false;
			}
		}
		catch(PDOException $e)
		{
			print $e->getMessage();
			die();
		}
	}
	public function cekSession()
	{
			if(isset($_SESSION['m_id']) && $_SESSION['m_level'] == 1 )
			{
				header('location:it-management/index.php');
				return true;
			} 
			else if(isset($_SESSION['m_id']) && $_SESSION['m_level'] == 4 )
			{
				header('location:it-management/index.php');
				return true;
			} 
			else
			{
				return false;
			}
	}
}


?>