login.php

<?php
	error_reporting(0);
    $koneksi = new mysqli("localhost","root","","a4_db");

    if($_SESSION['admin'] || $_SESSION['kasir'] ) {
        header("location:index.php");
    } else {
?>

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no" name="viewport">
    <title>Halaman Login</title>
</head>
<body>
    <h2>Halaman login</h2>
<form action="" method="POST">
    <ul>
        <li>
            <label>Username</label>
            <input type="text" name="username" placeholder="Username">
        </li>
    </ul>
    <ul>
        <li>
            <label>Password</label>
            <input type="password" name="password" placeholder="Password">
        </li>
    </ul>
</form>

<?php

    $username = $_POST['username'];
    $password = $_POST['password'];

    if( isset($_POST['login']) ) {

        $sql = $koneksi->query("select * from tb_user where user_id='$username' and pass='$password' ");

        $result = $sql->num_rows;
        $data = $sql->fetch_assoc();

            if( $result > 0 ) {

                if(password_verify($password, $data['pass'])) {

                    session_start();

                    $_SESSION['username'] = $data['user_id'];
                    $_SESSION['pass'] = $data['pass'];
                    $_SESSION['level'] = $data['level'];

                    if($data['level'] == "admin") {
                        $_SESSION['admin'] = $data[id];
                        header("location:index.php");

                    }else if($data['level'] == "kasir") {
                        $_SESSION['kasir'] = $data[id];
                        header("location:index.php");
            }

        } else {

                ?>
                    <script>
                        alert("Login Gagal Username dan Password Salah!!");
                    </script>
                <?php

            }

    }

?>

</body>
</html>

<?php } ?>