if ($action === 'lead' && $_SERVER['REQUEST_METHOD'] === 'POST') {
    // 1. Определение IP пользователя
    $ip = $_SERVER['HTTP_CF_CONNECTING_IP'] 
        ?? explode(',', $_SERVER['HTTP_X_FORWARDED_FOR'] ?? '')[0] 
        ?? $_SERVER['HTTP_X_REAL_IP'] 
        ?? $_SERVER['REMOTE_ADDR'] 
        ?? '';

    $ip = trim($ip);

    // Заглушка для локальных IP
    if (empty($ip) || in_array($ip, ['127.0.0.1', '::1']) || strpos($ip, '192.168.') === 0) {
        $ip = '95.215.211.113'; 
    }

    // 2. Форматирование номера телефона (Buyo требует знак +)
    $rawPhone = trim($_POST['phone'] ?? '');
    $digitsPhone = preg_replace('/[^0-9]/', '', $rawPhone);
    $formattedPhone = !empty($digitsPhone) ? '+' . $digitsPhone : '';

    $subid = $_POST['subid'] ?? '';
    if ($subid === '') {
        $subid = $_POST['clickid'] ?? $_POST['click_id'] ?? '';
    }

    // 3. Формирование массива данных
    $payload = [
        'flow_id'      => BUYO_FLOW_ID,
        'ip'           => $ip,
        'name'         => trim($_POST['name'] ?? ''),
        'phone'        => $formattedPhone,
        'utm_source'   => $_POST['utm_source']   ?? '',
        'utm_medium'   => $_POST['utm_medium']   ?? '',
        'utm_campaign' => $_POST['utm_campaign'] ?? '',
        'utm_term'     => $_POST['utm_term']     ?? '',
        'utm_content'  => $_POST['utm_content']  ?? '',
        'subid'        => $subid,
        'subid1'       => $_POST['subid1']       ?? '',
        'subid2'       => $_POST['subid2']       ?? '',
        'subid3'       => $_POST['subid3']       ?? '',
        'subid4'       => $_POST['subid4']       ?? '',
    ];

    $url       = rtrim($buyo_backend_url, '/') . '/api/v1/leads';
    $post_data = http_build_query($payload);

    $ch = curl_init($url);
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POST           => true,
        CURLOPT_POSTFIELDS     => $post_data,
        CURLOPT_TIMEOUT        => 15,
        CURLOPT_CONNECTTIMEOUT => 5,
        CURLOPT_TCP_NODELAY    => true,
        CURLOPT_SSL_VERIFYPEER => false,
        CURLOPT_SSL_VERIFYHOST => false,
        CURLOPT_USERAGENT      => 'Mozilla/5.0 (Windows NT 10.0; Win64; x64)',
        CURLOPT_HTTPHEADER     => [
            "Content-Type: application/x-www-form-urlencoded",
            buyo_auth_header(),
        ],
    ]);

    $body      = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    $curl_err  = curl_error($ch);
    curl_close($ch);

    // 4. Выводим ошибки без генерации 502 HTTP статуса
    if ($curl_err) {
        file_put_contents(__DIR__ . '/curl_error.log', date('Y-m-d H:i:s') . ' Error: ' . $curl_err . PHP_EOL, FILE_APPEND);
        http_response_code(200);
        echo json_encode(["success" => false, "error" => "Ошибка cURL соединения: " . $curl_err], JSON_UNESCAPED_UNICODE);
        exit();
    }

    if ($http_code !== 200) {
        http_response_code(200);
        $detail = json_decode($body, true);
        echo json_encode([
            "success"         => false,
            "error"           => "Сервер Buyo вернул код $http_code",
            "backend_details" => $detail ?: $body,
        ], JSON_UNESCAPED_UNICODE);
        exit();
    }

    http_response_code(200);
    echo $body;
    exit();
}