os/modules/nix/default.nix

{
  config,
  pkgs,
  lib,
  flake,
  ...
}: {
  nixpkgs.config.allowUnfreePredicate = pkg: builtins.elem (lib.getName pkg) [
    "steam"
    "steam-original"
    "steam-run"
    "hplip"
    "cups-brother-hl3140cw"
  ];

  nix = {
    # Use default version alias for nix package
    package = pkgs.nix;
    gc.automatic = true;
    optimise.automatic = true;

    settings = {
      # Improve nix store disk usage
      auto-optimise-store = true;
      # Prevents impurities in builds
      sandbox = true;
      # Give root and @wheel special privileges with nix
      trusted-users = ["root" "@wheel"];
      # Allow only group wheel to connect to the nix daemon
      allowed-users = ["@wheel"];
    };

    # Generally useful nix option defaults
    extraOptions = lib.mkForce ''
      experimental-features = flakes nix-command
      min-free = 536870912
      keep-outputs = true
      keep-derivations = true
      fallback = true
    '';

    nixPath = [
      "nixpkgs=${flake.inputs.nixpkgs}"
      "nixos-config=${../../lib/compat/nixos}"
      "home-manager=${flake.inputs.home-manager}"
    ];
  };
}