flutter:
  assets:
    - assets/html/

InAppWebView(
  onWebViewCreated: (controller) {
    _webViewController = controller;

    controller.addJavaScriptHandler(
      handlerName: 'adpxCallback',
      callback: (args) {
        if (args.length >= 2) {
          String event = args[0];
          String payload = args[1];
          _prefetchService.handleWebSDKEvent(event, payload);
        }
        return null;
      },
    );
  },
)

// prefetchWithWebSDK() replaces placeholders in prefetch.html
// with actual values, such as sdkId, payload, and config.
// It then loads the final HTML into the webview,
// which initializes the SDK in prefetch mode
Future<void> prefetchWithWebSDK(String sdkId, InAppWebViewController? webViewController) async {
  if (webViewController == null) throw Exception("WebView controller is not initialized");

  final payload = await createPayload();
  final htmlTemplate = await rootBundle.loadString('assets/html/prefetch.html');

  // Insert user config as window.AdpxUser
  String adpxUserConfigScript = '';
  if (payload.isNotEmpty) {
    adpxUserConfigScript = 'window.AdpxUser = {\n';
    payload.forEach((key, value) {
      adpxUserConfigScript += '  $key: "$value",\n';
    });
    adpxUserConfigScript = adpxUserConfigScript.replaceFirst(RegExp(r',\n$'), '\n') + '};\n';
  }

  // Inject into template
  String finalHtml = htmlTemplate
    .replaceAll('%%SDK_ID%%', sdkId)
    .replaceAll('%%SDK_CDN_URL%%', AppConfig.web.launcherScriptURL)
    .replaceFirst('window.AdpxUser = {};', adpxUserConfigScript);

  await webViewController.loadData(
    data: finalHtml,
    mimeType: 'text/html',
    encoding: 'utf-8',
    baseUrl: WebUri('https://myapp.local'), // Avoid using about:blank to prevent WebView security errors
  );

  debugPrint('WebSDK prefetch initialized with SDK ID: $sdkId');
}

POST https://api.adspostx.com/native/v4/offers.json

Future<Map<String, dynamic>> fetchOffers({
  required String sdkId,
  bool isDevelopment = false,
  Map<String, String>? payload,
  String? loyaltyboost,
  String? creative,
  String? campaignId,
}) async {
  if (loyaltyboost != null && !['0', '1', '2'].contains(loyaltyboost)) {
    throw NetworkException(NetworkError.invalidParameter, 'loyaltyboost must be 0, 1, or 2');
  }

  if (creative != null && !['0', '1'].contains(creative)) {
    throw NetworkException(NetworkError.invalidParameter, 'creative must be 0 or 1');
  }

  try {
    final uri = Uri.parse(AppConfig.api.baseURL);
    final queryParams = {
      'api_key': sdkId,
      if (loyaltyboost != null) 'loyaltyboost': loyaltyboost,
      if (creative != null) 'creative': creative,
      if (campaignId != null) 'campaignId': campaignId,
    };

    final url = Uri(
      scheme: uri.scheme,
      host: uri.host,
      path: uri.path,
      queryParameters: queryParams,
    );

    final requestBody = <String, dynamic>{};
    if (isDevelopment) requestBody['dev'] = '1';
    if (payload != null) requestBody.addAll(payload);

    final String userAgent = payload?['ua'] ?? await DeviceUtils.getUserAgent();
    final jsonBody = jsonEncode(requestBody);

    final response = await _client.post(
      url,
      headers: {
        'Content-Type': 'application/json',
        'User-Agent': userAgent,
      },
      body: jsonBody,
    );

    if (response.statusCode >= 200 && response.statusCode < 300) {
      return jsonDecode(response.body) as Map<String, dynamic>;
    } else {
      throw NetworkException(
        NetworkError.serverError,
        'Server returned error: ${response.statusCode}',
      );
    }
  } catch (e) {
    debugPrint('Network error: $e');
    throw NetworkException(
      NetworkError.connectionError,
      'Failed to connect: ${e.toString()}',
    );
  }
}

Navigator.push(
  context,
  MaterialPageRoute(
    builder: (context) => CheckoutScreen(
      sdkId: _sdkIdController.text.trim(),
      prefetchMethod: prefetchMethod, // you may not need this parameter as you are going to use only one of the approach.
      apiResponse: apiResponse, // Only required for API prefetch
      offerCount: _offerCount, // Optional, require only if you want to show no of offers in UI.
      payload: payload,
    ),
  ),
);

Future<NavigationActionPolicy> handleUrlNavigation(NavigationAction navigationAction) async {
  final uri = navigationAction.request.url;
  if (uri != null) {
    await Future.delayed(const Duration(seconds: 1));

    final url = uri.toString();
    final normalizedUrl = _normalizeUrl(url);
    debugPrint('Intercepted URL: $normalizedUrl');

    if (_externallyOpenedUrls.contains(normalizedUrl)) {
      debugPrint('Canceling navigation for externally opened URL: $normalizedUrl');
      return NavigationActionPolicy.CANCEL;
    }

    return NavigationActionPolicy.ALLOW;
  }

  return NavigationActionPolicy.CANCEL;
}