getModelFilePaths method

Implementation

@override
Future<Map<String, String>?> getModelFilePaths(ModelSpec spec) async {
  await _ensureInitialized();

  // Phase 5: Delegate to Modern API
  final registry = ServiceRegistry.instance;
  final repository = registry.modelRepository;
  final fileSystem = registry.fileSystemService as WebFileSystemService;

  // Check installation via repository
  bool allFilesInstalled = true;
  for (final file in spec.files) {
    if (!await repository.isInstalled(file.filename)) {
      allFilesInstalled = false;
      break;
    }
  }

  if (!allFilesInstalled) {
    return null;
  }

  final filePaths = <String, String>{};

  for (final file in spec.files) {
    // Get URL from WebFileSystemService based on source type
    final String path;

    if (file.source is NetworkSource) {
      // Web: Get registered URL (blob URL for auth downloads)
      // If URL lost (page reload), restore from Cache API
      var url = fileSystem.getUrl(file.filename);
      if (url == null) {
        gemmaLog(
            '[WebModelManager] Blob URL lost for ${file.filename}, restoring from cache...');

        // Try to restore from Cache API
        final networkSource = file.source as NetworkSource;
        final downloadService =
            registry.downloadService as WebDownloadService;
        final cacheService = downloadService.cacheService;

        // Get cached blob URL (cache service handles URL normalization internally)
        final cachedBlobUrl =
            await cacheService.getCachedBlobUrl(networkSource.url);
        if (cachedBlobUrl != null) {
          gemmaLog(
              '[WebModelManager] ✅ Restored blob URL from cache: $cachedBlobUrl');
          // Re-register the blob URL
          fileSystem.registerUrl(file.filename, cachedBlobUrl);
          url = cachedBlobUrl;
        } else {
          // Cached blob is gone and the auth token is not persisted across
          // restarts (ModelSource.encode drops it). Falling back to the
          // original URL works for PUBLIC models but a GATED model will fail
          // the fetch later with an opaque network error. Surface it now at a
          // visible level so the cause (re-auth / re-install needed) is clear.
          gemmaLog(
              '[WebModelManager] ⚠️  "${file.filename}" not in cache; falling back to original URL ${networkSource.url}. '
              'If this model is gated/private, the load will fail (auth token is not restored) — re-install the model to re-authenticate.');
        }
      }
      path = url ?? (file.source as NetworkSource).url;
    } else if (file.source is BundledSource) {
      // Web: Bundled resources
      path = await fileSystem.getBundledResourcePath(
          (file.source as BundledSource).resourceName);
    } else if (file.source is AssetSource) {
      // Web: Get registered Blob URL (created by WebAssetSourceHandler)
      // If URL lost (page reload), recreate it
      var url = fileSystem.getUrl(file.filename);
      if (url == null) {
        gemmaLog(
            '[WebModelManager] Blob URL lost for ${file.filename}, recreating from asset...');
        // Recreate Blob URL by reinstalling
        final handler =
            registry.sourceHandlerRegistry.getHandler(file.source);
        if (handler != null) {
          await handler.install(file.source);
          url = fileSystem.getUrl(file.filename);
        }
      }
      path = url ?? (file.source as AssetSource).normalizedPath;
    } else if (file.source is FileSource) {
      // Web: External URL or registered path
      final fileSource = file.source as FileSource;
      path = fileSystem.getUrl(file.filename) ?? fileSource.path;
    } else {
      // Fallback: use getTargetPath
      path = await fileSystem.getTargetPath(file.filename);
    }

    filePaths[file.prefsKey] = path;
  }

  return filePaths.isNotEmpty ? filePaths : null;
}