
<?php
// Show PHP errors (for testing)
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

// Handle form submission
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $email = filter_var(trim($_POST["email"]), FILTER_SANITIZE_EMAIL);

    if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
        $file = "emails.txt";

        // Check for duplicates before writing
        if (file_exists($file)) {
            $existingEmails = file($file, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
            if (in_array($email, $existingEmails)) {
                echo "This email is already subscribed.";
                exit;
            }
        }

        // Save email to file
        file_put_contents($file, $email . PHP_EOL, FILE_APPEND);
        echo "Thanks for subscribing!";
    } else {
        echo "Please enter a valid email address.";
    }
}
?>