{ inputs, self, ... }: {
  flake.nixosModules.global = { config, pkgs, lib, ... }: {
    options.features.shells.defaultShell = lib.mkOption {
      type = lib.types.enum (map (name: lib.removeSuffix ".nix" name) (
        builtins.attrNames (builtins.readDir "${self}/modules/features/shells")
      ));
      default = "zsh";
    };

    config = {
      programs.${config.features.shells.defaultShell}.enable = true;

      users.defaultUserShell = pkgs.${config.features.shells.defaultShell};
      users.users."grey".shell = pkgs.${config.features.shells.defaultShell};
    };
  };
}