{
  # Snowfall Lib provides a customized `lib` instance with access to your flake's library
  # as well as the libraries available from your flake's inputs.
  lib,
  # An instance of `pkgs` with your overlays and packages applied is also available.
  pkgs,
  # You also have access to your flake's inputs.
  inputs,

  # Additional metadata is provided by Snowfall Lib.
  namespace, # The namespace used for your flake, defaulting to "internal" if not set.
  system, # The system architecture for this host (eg. `x86_64-linux`).
  target, # The Snowfall Lib target for this system (eg. `x86_64-iso`).
  format, # A normalized name for the system target (eg. `iso`).
  virtual, # A boolean to determine whether this system is a virtual target using nixos-generators.
  systems, # An attribute map of your defined hosts.

  # All other arguments come from the module system.
  config,
  ...
}:

let
  cfg = config.modules.virtualbox;
in
{
  options.modules.virtualbox = {
    enable = lib.mkOption { default = false; };
  };

  config = lib.mkIf cfg.enable {
    virtualisation.virtualbox.host.enable = true;
    # virtualisation.virtualbox.host.enableExtensionPack = true;
    # virtualisation.virtualbox.guest.enable = true;
    # virtualisation.virtualbox.guest.x11 = true;
    users.extraGroups.vboxusers.members = [ "julian" ];
  };
}
