puzzlevision/modules/nixos/common/nix/default.nix

{
  lib,
  pkgs,
  inputs,
  namespace,
  config,
  ...
}: with lib; with lib.${namespace};
let
  cfg = config.${namespace}.common.nix;
in {
  options.${namespace}.common.nix = {
    enable = mkEnableOption "Overwrite the default Nix configuration.";
    use-lix = mkEnableOption "Enable Lix as an alternative to CppNix.";
  };

  config = mkIf cfg.enable {
    nix = {
      settings = {
        auto-optimise-store = true;
        builders-use-substitutes = true;
        experimental-features = [ "nix-command" "flakes" ];
        keep-derivations = true;
        keep-outputs = true;
        max-jobs = "auto";
      };

      # Garbage collection configuration.
      gc = {
        automatic = true;
        dates = "daily";
        options = "--delete-older-than 3d";
      };

      package = mkIf cfg.use-lix pkgs.lix; # Enable LIX
    };
  };
}