Simple PHP Login

admin.php

<?php session_start();

if(isset($_SESSION['username'])){
  echo "Hi Admin, user kamu ".$_SESSION["username"];
}else{
  header('Location: index.php');
}

?>

index.php

<?php session_start();
error_reporting(0);
// Login Logic

$post_user = $_POST["user"];
$post_pass = $_POST["pass"];

if(isset($post_user) && isset($post_pass)){
  check_login($post_user,$post_pass);
}

// Jika Logout
if(isset($_GET["logout"])){
  session_destroy();
  header('Location: index.php');
}

// Chek user udah login belum
if(isset($_SESSION["username"])){
  echo "Anda login sebagai ".$_SESSION["username"]." <a href='?logout=true'>Metu</a>";
}


// Function
function check_login($username,$pass){
  $base_user = "admin";
  $base_pass = "admin";

  if($username == $base_user && $pass == $base_pass){
    // Set sesi login
    $_SESSION["username"] = $username;
  }else{
    echo "Wadefak, lali password e?";
  }

}
?>

<form action="index.php" method="post">
  <input type="text" name="user"/>
  <input type="password" name="pass"/>
  <input type="submit" name="Login"/>

</form>