创建用户个人资料页面

I am creating profile page I will distinguish if user is visiting own profile or other users with this simple code

if(isset($_GET['username']) && !empty($_GET['username'])) { 
$username = $_GET['username'];
}
else {
$username = $_SESSION['username'];
}

Now the problem is I am using session and cookies both for auto-login feature. On header.php and accountsettings.php I am defining username like this:

if(isset($_SESSION['username'])) {
  $username = $_SESSION['username'];
}
else if(isset($_COOKIE['username'])){
  $username = $_COOKIE['username'];
}
else
{
 //invalid ---
}

This code works fine for both pages, so how to set username on profile page where it checks if $_GET['username'], or if $_SESSION['username'] or $_COOKIE['username']

Try this code

if(!empty($_GET['username'])) { 
$username = $_GET['username'];
}
else if(!empty($_SESSION['username'])) { 
$username = $_SESSION['username'];
}
else if(!empty($_COOKIE['username'])) { 
$username = $_COOKIE['username'];
}else{
echo 'username not found';die;
}