upload :: Verbosity -> [Repo] -> Maybe Username -> Maybe Password -> [FilePath] -> IO ()
upload verbosity repos mUsername mPassword paths = do
          let uploadURI = if isOldHackageURI targetRepoURI
                          then legacyUploadURI
                          else targetRepoURI{uriPath = uriPath targetRepoURI `FilePath.Posix.combine` "upload"}
          Username username <- maybe promptUsername return mUsername
          Password password <- maybe promptPassword return mPassword
          let auth = addAuthority AuthBasic {
                       auRealm    = "Hackage",
                       auUsername = username,
                       auPassword = password,
                       auSite     = uploadURI
                     }
          flip mapM_ paths $ \path -> do
            notice verbosity $ "Uploading " ++ path ++ "... "
            handlePackage verbosity uploadURI auth path
  where
    targetRepoURI = remoteRepoURI $ last [ remoteRepo | Left remoteRepo <- map repoKind repos ] --FIXME: better error message when no repos are given