PHP联系人表单失败

<form action="submit_form.php" method="post">
    <input type="text" name="name" placeholder="Your Name">
    <input type="email" name="email" placeholder="Your Email">
    <textarea name="message" placeholder="Your Message"></textarea>
    <button type="submit">Submit</button>
</form>

<?php
error_reporting(E_ALL);
ini_set('display_errors', 1);

$name = $_POST['name'];
$email = $_POST['email'];
$message = $_POST['message'];

// 简单的验证
if (empty($name) || empty($email) || empty($message)) {
    die("All fields are required.");
}

// 发送邮件
$to = "admin@example.com";
$subject = "New Contact Form Submission";
$body = "Name: $name\nEmail: $email\nMessage: $message";

if (mail($to, $subject, $body)) {
    echo "Thank you for your message!";
} else {
    echo "There was an error sending your message.";
}
?>

<?php
require 'PHPMailer/src/PHPMailer.php';
require 'PHPMailer/src/SMTP.php';
require 'PHPMailer/src/Exception.php';

$mail = new PHPMailer\PHPMailer\PHPMailer();
$mail->isSMTP();
$mail->Host = 'smtp.example.com';
$mail->SMTPAuth = true;
$mail->Username = 'your_email@example.com';
$mail->Password = 'your_password';
$mail->SMTPSecure = 'tls';
$mail->Port = 587;

$mail->setFrom('from@example.com', 'Mailer');
$mail->addAddress('admin@example.com', 'Admin');

$mail->Subject = 'New Contact Form Submission';
$mail->Body    = "Name: $name\nEmail: $email\nMessage: $message";

if(!$mail->send()) {
    echo 'Message could not be sent.';
    echo 'Mailer Error: ' . $mail->ErrorInfo;
} else {
    echo 'Message has been sent';
}
?>

<form action="submit_form.php" method="post">
    <input type="hidden" name="csrf_token" value="<?php echo generate_csrf_token(); ?>">
    <input type="text" name="name" placeholder="Your Name">
    <input type="email" name="email" placeholder="Your Email">
    <textarea name="message" placeholder="Your Message"></textarea>
    <button type="submit">Submit</button>
</form>

<?php
session_start();

function generate_csrf_token() {
    if (empty($_SESSION['csrf_token'])) {
        $_SESSION['csrf_token'] = bin2hex(random_bytes(32));
    }
    return $_SESSION['csrf_token'];
}

if ($_POST['csrf_token'] !== $_SESSION['csrf_token']) {
    die("Invalid CSRF token.");
}

// 继续处理表单数据...
?>