PHP を使用して、電子メール検証機能を備えた安全なログインおよび登録システムを作成するにはどうすればよいですか?

CREATE TABLE users (
id INT(11) AUTO_INCREMENT PRIMARY KEY,
username VARCHAR(255) NOT NULL,
email VARCHAR(255) NOT NULL,
password VARCHAR(255) NOT NULL,
verified INT(1) NOT NULL DEFAULT 0
);

<?php
// 获取表单输入数据
$username = $_POST['username'];
$email = $_POST['email'];
$password = $_POST['password'];

// 验证用户输入

// 检查用户名是否已被注册

// 检查邮箱格式是否正确

// 生成一个随机验证码字符串
$verificationCode = bin2hex(random_bytes(16));

// 将用户信息保存到数据库
$query = "INSERT INTO users (username, email, password, verification_code) VALUES ('$username', '$email', '$password', '$verificationCode')";
mysqli_query($connection, $query);

// 发送验证邮件
$to = $email;
$subject = '账号激活邮件';
$message = '请点击以下链接激活您的账号：https://example.com/verify.php?code=' . $verificationCode;
$headers = 'From: noreply@example.com' . "
" .
'Reply-To: noreply@example.com' . "
" .
'X-Mailer: PHP/' . phpversion();

mail($to, $subject, $message, $headers);

// 提示用户验证邮件已发送
echo '注册成功！请检查您的邮箱并点击验证链接进行账号激活。';
?>

<?php
$verificationCode = $_GET['code'];

// 在数据库中查找匹配的验证代码
$query = "SELECT * FROM users WHERE verification_code = '$verificationCode' LIMIT 1";
$result = mysqli_query($connection, $query);

// 如果找到匹配的验证代码，更新用户的“verified”字段
if (mysqli_num_rows($result) > 0) {
    $user = mysqli_fetch_assoc($result);
    $userId = $user['id'];

    $updateQuery = "UPDATE users SET verified = 1 WHERE id = '$userId'";
    mysqli_query($connection, $updateQuery);

    echo '邮箱验证成功！您可以登录了。';
} else {
    echo '无效的验证链接。';
}
?>

<?php
$email = $_POST['email'];
$password = $_POST['password'];

// 在数据库中查找匹配的邮箱和密码
$query = "SELECT * FROM users WHERE email = '$email' AND password = '$password' LIMIT 1";
$result = mysqli_query($connection, $query);

// 如果找到匹配的记录，表示登录成功
if (mysqli_num_rows($result) > 0) {
    $user = mysqli_fetch_assoc($result);
    $verified = $user['verified'];

    if ($verified) {
        echo '登录成功！';
    } else {
        echo '账号尚未激活，请检查您的邮箱并点击验证链接进行账号激活。';
    }
} else {
    echo '邮箱或密码输入错误。';
}
?>