nixos-config/home-manager/lib.nix

let
  inherit (import ../common/lib.nix) home-manager writeHaskellScript get-niv-path;
in
{
  update-home = configPath: writeHaskellScript
    {
      name = "update-home";
      bins = [
        get-niv-path
        home-manager
      ];
    }
    ''

    getNivPath = get_niv_path "${configPath}/nix/sources.nix"

    getNivAssign name = (tag <$>) . readTrim . getNivPath $ name
      where tag str = ["-I", [i|#{name}=#{str :: LBS.ByteString}|]]

    main = do
      args <- getArgs
      paths <- concat <$> mapM getNivAssign ["home-manager", "nixpkgs", "unstable"]
      home_manager $ paths ++ ["switch"] ++ args
    '';
}