from data.database import ImageStorage, ManifestBlob
from data.model import BlobDoesNotExist
from data.model.storage import get_storage_by_subquery, InvalidImageException
from data.model.blob import get_repository_blob_by_digest as legacy_get

def get_repository_blob_by_digest(repository, blob_digest):
  """ Find the content-addressable blob linked to the specified repository and
      returns it or None if none.
  """
  try:
    storage_id_query = (ImageStorage
                        .select(ImageStorage.id)
                        .join(ManifestBlob)
                        .where(ManifestBlob.repository == repository,
                               ImageStorage.content_checksum == blob_digest,
                               ImageStorage.uploading == False)
                        .limit(1))

    return get_storage_by_subquery(storage_id_query)
  except InvalidImageException:
    # TODO(jschorr): Remove once we are no longer using the legacy tables.
    # Try the legacy call.
    try:
      return legacy_get(repository, blob_digest)
    except BlobDoesNotExist:
      return None