<?php
// Start session to manage user login state
session_start();

// Define a hardcoded user for demonstration purposes (In a real app, use a database)
$valid_username = "admin";
$valid_password = "password123"; 

$error_msg = "";

// Check if form is submitted
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $username = trim($_POST['username']);
    $password = trim($_POST['password']);

    if ($username === $valid_username && $password === $valid_password) {
        // Successful login
        $_SESSION['loggedin'] = true;
        $_SESSION['username'] = $username;
        // Redirect to the dashboard page
        header("Location: dashboard.php"); 
        exit;
    } else {
        $error_msg = "Invalid username or password.";
    }
}
?>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Login | WAHTTEX 2026</title>
    <!-- Favicon Placeholder -->
    <link rel="shortcut icon" href="images/favicon.ico" type="image/x-icon">
    <!-- Tailwind CSS -->
    <script src="https://cdn.tailwindcss.com"></script>
    <link href="https://fonts.googleapis.com/css2?family=Montserrat:wght@600;700&family=Open+Sans:wght@400;600&display=swap" rel="stylesheet">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css">
    
    <style>
         :root {
            --primary-red: #B91C1C; 
            --accent-gold: #F59E0B; 
            --accent-green: #15803D; 
        }
        body { font-family: 'Open Sans', sans-serif; background-color: #f3f4f6; }
        h1, h2 { font-family: 'Montserrat', sans-serif; }
        
        /* Subtle background pattern */
        .bg-pattern {
             background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23B91C1C' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
        }
    </style>
</head>
<body class="min-h-screen flex items-center justify-center bg-pattern">

    <div class="bg-white w-full max-w-md rounded-2xl shadow-2xl overflow-hidden border-t-8 border-yellow-500">
        
        <!-- Header Section -->
        <div class="bg-red-700 p-8 text-center relative overflow-hidden">
            <div class="absolute top-0 right-0 w-24 h-24 bg-yellow-500 rounded-full mix-blend-multiply filter blur-xl opacity-50 animate-blob"></div>
            <div class="absolute -bottom-8 -left-8 w-24 h-24 bg-green-600 rounded-full mix-blend-multiply filter blur-xl opacity-50 animate-blob"></div>
            
            <h2 class="text-3xl font-bold text-white relative z-10">Welcome Back</h2>
            <p class="text-red-100 mt-2 relative z-10 font-medium">Exhibitor & Partner Login</p>
        </div>

        <!-- Login Form -->
        <div class="p-8">
            <?php if(!empty($error_msg)): ?>
                <div class="bg-red-50 border-l-4 border-red-500 text-red-700 p-4 mb-6 text-sm rounded-r" role="alert">
                    <p class="font-bold">Error</p>
                    <p><?php echo $error_msg; ?></p>
                </div>
            <?php endif; ?>

            <form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="POST">
                <div class="mb-6">
                    <label class="block text-gray-700 text-sm font-bold mb-2" for="username">
                        Username
                    </label>
                    <div class="relative group">
                        <span class="absolute inset-y-0 left-0 flex items-center pl-3 text-gray-400 group-focus-within:text-red-600 transition">
                            <i class="fa-solid fa-user"></i>
                        </span>
                        <input class="w-full border-gray-300 border-2 rounded-lg py-3 pl-10 pr-3 focus:outline-none focus:border-red-600 focus:ring-0 transition bg-gray-50 focus:bg-white" 
                               id="username" name="username" type="text" placeholder="Enter your username" required>
                    </div>
                </div>

                <div class="mb-8">
                    <label class="block text-gray-700 text-sm font-bold mb-2" for="password">
                        Password
                    </label>
                    <div class="relative group">
                        <span class="absolute inset-y-0 left-0 flex items-center pl-3 text-gray-400 group-focus-within:text-red-600 transition">
                            <i class="fa-solid fa-lock"></i>
                        </span>
                        <input class="w-full border-gray-300 border-2 rounded-lg py-3 pl-10 pr-3 focus:outline-none focus:border-red-600 focus:ring-0 transition bg-gray-50 focus:bg-white" 
                               id="password" name="password" type="password" placeholder="******************" required>
                    </div>
                </div>

                <div class="flex items-center justify-between mb-6">
                    <a href="index.html" class="text-sm text-gray-500 hover:text-red-600 font-semibold transition">
                        <i class="fa-solid fa-arrow-left mr-1"></i> Back to Home
                    </a>
                    <button class="bg-red-700 hover:bg-red-800 text-white font-bold py-3 px-8 rounded-full focus:outline-none shadow-lg transform active:scale-95 transition duration-150 ease-in-out" 
                            type="submit">
                        Sign In
                    </button>
                </div>
            </form>
        </div>
        
        <div class="bg-gray-50 px-8 py-4 border-t border-gray-200 text-center">
            <p class="text-xs text-gray-600">
                Don't have an account? <a href="#" class="text-green-700 font-bold hover:underline">Register for WAHTTEX 2026</a>
            </p>
        </div>
    </div>

</body>
</html>