{
  description = "Home Manager configuration of john";

  inputs = {
    # Specify the source of Home Manager and Nixpkgs.
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    home-manager = {
      url = "github:nix-community/home-manager";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs =
    { nixpkgs, home-manager, ... }:
    let
      system = "x86_64-linux";
      pkgs = nixpkgs.legacyPackages.${system};
      lib = pkgs.lib;
      
      # Define a module that contains the user option
      userModule = { config, ... }: {
        options.user = lib.mkOption {
          type = lib.types.str;
          description = "The username for the Home Manager configuration.";
          default = "john";
        };
      };
      
      # Evaluate the module to get the config
      moduleEval = lib.evalModules {
        modules = [ userModule ];
      };
      
      username = moduleEval.config.user;
    in
    {
      homeConfigurations.${username} = home-manager.lib.homeManagerConfiguration {
        inherit pkgs;

        # Specify your home configuration modules here, for example,
        # the path to your home.nix.
        modules = [ 
          ./home.nix 
          userModule  # Include the user module in Home Manager modules too
        ];

        # Optionally use extraSpecialArgs
        # to pass through arguments to home.nix
      };
    };
}