{ nixpkgs }:
with nixpkgs.lib; {
  # list nix files from a specific directory dir
  nixFilesIn = dir:
    { filterRule ? (name: _: name) }:
    builtins.attrValues (builtins.mapAttrs (name: _: name)
      (filterAttrs filterRule (builtins.readDir dir)));

  importModulesIn = dir:
    let
      modules = nixFilesIn dir { filterRule = (name: _: (lib.hasSuffix ".nix" name)); };
    in
    builtins.foldl'
      (imports: mod: imports // (import (./. + "/${dir}/${mod}")
        #{
        #  pkgs = pkgs;
        #}
      ))
      { }
      modules;

}