index.php

<?php 
session_start();

// Check if the user is logged in, then redirect them to the welcome page directly
if (!isset($_SESSION["loggedin"])) {


include 'db.php'; // Include your database connection

include 'header.php'; // Include your header.php file
?>

<!-- empty div to make the theme works -->
<div id="subjectForm"></div>

<div class="container">
    <select onchange="saveThemePreference(this.value)">
        <option value="system">Theme | System Default</option>
        <option value="light">Light</option>
        <option value="dark">Dark</option>
    </select>
    <h1>Study Reminder</h1>

    <!-- Toggling Forms for Login and Registration -->
    <div>
        <button onclick="showForm('login')">Login</button>
        <button onclick="showForm('register')">Register</button>
    </div>

    <div id="loginForm" style="display:none;">
        <h2>Login</h2>
        <form method="post" action="login.php">
            Username: <input type="text" name="username" required><br>
            Password: <input type="password" name="password" required><br>
            <button type="submit">Login</button>
        </form>
    </div>

    <div id="registerForm" style="display:none;">
        <h2>Register</h2>
        <form method="post" action="register.php">
            Username: <input type="text" name="username" required><br>
            Email: <input type="email" name="email" required><br>
            Password: <input type="password" name="password" required><br>
            <button type="submit">Register</button>
        </form>
    </div>

    <div id="subjectsContainer"></div>

    <footer>
        <p>Copyright &copy; Mohammed Q.Sattar Services</p>
    </footer>
</div>

<script src="script.js"></script>

<script>
function showForm(form) {
    document.getElementById('loginForm').style.display = form === 'login' ? 'block' : 'none';
    document.getElementById('registerForm').style.display = form === 'register' ? 'block' : 'none';
    document.getElementById('subjectForm').style.display = form === 'login' || form === 'register' ? 'none' :
        'block';
}
</script>
</body>

</html>

<?php
}else{
    header("location: welcome.php");
    exit;
}
?>