{ lib, ... }:
let
  machineOpts = { config, ... }: {
    options = {
      arch = lib.mkOption {
        default = null;
        type = with lib.types; nullOr str;
        description = ''
          CPU architecture of this machine.
        '';
      };

      isRaspberryPi = lib.mkOption {
        default = false;
        type = lib.types.bool;
      };

      nixosModule = lib.mkOption {
        default = { ... }: { };
        type = lib.types.anything;
        description = ''
          Customized configuration for this machine in the form of a NixOS module.
        '';
      };
    };
  };
in
{
  imports = [
    ./warwick.nix
    ./atlas.nix
    ./jefke.nix
    ./lewis.nix
  ];

  options = {
    machines = lib.mkOption {
      type = with lib.types; attrsOf (submodule machineOpts);
    };
  };
}