downloadModel function

Future<String> downloadModel({ required WhisperModel model, required String destinationPath, String? downloadHost, dynamic onDownloadProgress(int received, int total)?, })

Download model to destinationPath

Throws ModelException if download fails.

Implementation

Future<String> downloadModel({
  required WhisperModel model,
  required String destinationPath,
  String? downloadHost,
  Function(int received, int total)? onDownloadProgress,
}) async {
  if (kDebugMode) {
    debugPrint('Download model ${model.modelName}');
  }

  final httpClient = HttpClient();
  File? file;

  try {
    Uri modelUri;

    if (downloadHost == null || downloadHost.isEmpty) {
      /// Huggingface url to download model
      modelUri = Uri.parse(
        'https://huggingface.co/ggerganov/whisper.cpp/resolve/main/ggml-${model.modelName}.bin',
      );
    } else {
      modelUri = Uri.parse(
        '$downloadHost/ggml-${model.modelName}.bin',
      );
    }

    final request = await httpClient.getUrl(modelUri);
    final response = await request.close();

    // Check for HTTP errors
    if (response.statusCode != 200) {
      throw ModelException.downloadFailed(
        model.modelName,
        'HTTP ${response.statusCode}',
      );
    }

    final contentLength = response.contentLength;
    if (kDebugMode) {
      debugPrint('Content length: $contentLength bytes');
    }

    file = File('$destinationPath/ggml-${model.modelName}.bin');
    final raf = file.openSync(mode: FileMode.write);

    int receivedBytes = 0;
    await for (var chunk in response) {
      raf.writeFromSync(chunk);
      receivedBytes += chunk.length;

      // Call progress callback if provided
      if (onDownloadProgress != null && contentLength > 0) {
        onDownloadProgress(receivedBytes, contentLength);
      }
    }

    await raf.close();

    // Validate downloaded file
    if (!file.existsSync() || file.lengthSync() == 0) {
      throw ModelException.downloadFailed(
        model.modelName,
        'Downloaded file is empty or missing',
      );
    }

    if (kDebugMode) {
      debugPrint('Download Done . Path = ${file.path}');
    }
    return file.path;
  } on ModelException {
    rethrow;
  } on SocketException catch (e) {
    throw ModelException.downloadFailed(
        model.modelName, 'Network error: ${e.message}');
  } on HttpException catch (e) {
    throw ModelException.downloadFailed(
        model.modelName, 'HTTP error: ${e.message}');
  } catch (e) {
    // Clean up partial download on failure
    if (file != null && file.existsSync()) {
      try {
        file.deleteSync();
      } catch (_) {}
    }
    throw ModelException.downloadFailed(model.modelName, e.toString());
  }
}