Untitled

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>PHP - Login</title>
</head>
<body>
    <?php

    function isUserLogged() {
        if (isset($_SESSION['logged']) && $_SESSION['logged'] === 1)
            return true;
        return false;
    }

    function getUser() {
        return [
            'login' => 'admin',
            'password' => '123',
        ];
    }

    function login($login, $password) {
        $user = getUser();

        if ($login === $user['login'] && $password === $user['password']) {
            $_SESSION['login'] = $user['login'];
            $_SESSION['password'] = $user['password'];
            $_SESSION['logged'] = 1;
            return true;
        } else {
            return false;
        }
    }

    session_start();

    if (isset($_POST['submit'])) {
        $data = $_POST;

        // print_r($data); // DEBUG

        if (!login($data['login'], $data['password'])) {
            echo "Login e/ou senha incorreta!";
        }
    }

    ?>

    <?php if (isUserLogged()) : ?>
        <h1>User Panel</h1>
        <p>
            Login: <strong><?= getUser()['login'] ?></strong>
            <br> Password: <strong><?= getUser()['password'] ?></strong>
        </p>
    <?php else : ?>
        <form action="#" method="post">
            <label for="login">Login:</label>
            <input type="text" name="login" id="login" required>
            <br>
            <label for="password">Password:</label>
            <input type="password" name="password" id="password" required>
            <br>
            <button type="submit" name="submit">Login</button>
        </form>
    <?php endif; ?>
</body>
</html>