openPdf method

@override Future<String?> openPdf({ required String filePath, required String password, File? webFile, })

Implementation

@override
Future<String?> openPdf({
  required String
  filePath, // filePath is less relevant on web, we need the actual file bytes
  required String password,
  html.File? webFile, // This should be passed from file_picker on web
}) async {
  if (webFile == null) {
    throw PlatformException(
      code: "MISSING_FILE_WEB",
      message: "Web file data not provided for openPdf.",
    );
  }
  print('[Web] openPdf called for ${webFile.name}');

  final completer = Completer<String?>();
  final reader = html.FileReader();
  reader.readAsArrayBuffer(webFile); // Read file as ArrayBuffer

  reader.onLoadEnd.listen((event) async {
    if (reader.readyState == html.FileReader.DONE) {
      final Uint8List fileBytes = reader.result as Uint8List;
      print(
        '[Web] openPdf: File read, ${fileBytes.lengthInBytes} bytes. Password: "$password"',
      );
      try {
        // Call a JavaScript function that uses PDF.js
        // This JS function will take fileBytes and password,
        // and return a Blob URL of the (potentially decrypted) PDF.
        final jsPromise = js_util.callMethod(
          html.window,
          '_webDecryptPdfToBlobUrl',
          [fileBytes, password],
        );
        final String? blobUrl = await js_util.promiseToFuture(
          jsPromise as Object,
        );
        if (blobUrl != null) {
          print('[Web] openPdf: Success, Blob URL: $blobUrl');
          completer.complete(blobUrl);
        } else {
          print('[Web] openPdf: Failed, JS returned null Blob URL.');
          completer.completeError(
            PlatformException(
              code: 'WEB_DECRYPTION_FAILED',
              message: 'PDF.js processing failed to return a Blob URL.',
            ),
          );
        }
      } catch (e) {
        print('[Web] openPdf: Error during JS call: ${e.toString()}');
        completer.completeError(
          PlatformException(
            code: 'WEB_JS_CALL_ERROR',
            message:
                'Error calling PDF.js interop for openPdf: ${e.toString()}',
          ),
        );
      }
    } else {
      print('[Web] openPdf: FileReader not DONE.');
      completer.completeError(
        PlatformException(
          code: 'WEB_FILE_READ_INCOMPLETE',
          message: 'Web file reading was not completed.',
        ),
      );
    }
  });

  reader.onError.listen((event) {
    print('[Web] openPdf: FileReader error.');
    completer.completeError(
      PlatformException(
        code: 'WEB_FILE_READ_ERROR',
        message: 'Error reading web file for openPdf.',
      ),
    );
  });

  return completer.future;
}