nixos/configuration.nix

{lib, ...}:
with builtins;
with lib; let
  fn = import (toString ./fn.nix) {inherit lib;};
  # Cannot use <hostName> here as those evaluations only work with existing paths >.<
  # hostName and secretPtah can be set with -I hostName=$HOSTNAME and -I secretPath=$SECRETPATH respectively
  # , defaults to the contents of /secret/hostName
  secretPath =
    fn.ifelse ((tryEval (toString <secretPath>)).value != false)
    (toString <secretPath>)
    (toString /secret);
  hostName =
    (
      findFirst
      (elem: elem.prefix == "hostName")
      {path = fileContents "${secretPath}/hostName";}
      nixPath
    )
    .path;
  machinePath = builtins.toPath (./machines + ("/" + hostName));
  machineFiles = fn.lst {
    p = machinePath;
    b = true;
  };
  configFiles = fn.lst {
    p = toString ./config;
    b = true;
  };
  pkgsFiles = fn.lst {
    p = toString ./pkgs;
    b = true;
  };
  serviceFiles = fn.lst {
    p = toString ./services;
    b = true;
  };
in {
  imports =
    [
      ./options/machine.nix
      ./services/mailserver/default.nix
    ]
    ++ machineFiles
    ++ configFiles
    ++ pkgsFiles
    ++ serviceFiles;
}