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

{
  lib,
  pkgs,
  inputs,

  namespace, # The flake namespace, set in flake.nix. If not set, defaults to "internal".
  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.

  config,
  ...
}: with lib; with lib.${namespace};
let
  cfg = config.${namespace}.common.shell;
in {
  options.${namespace}.common.shell = {
    enable = mkEnableOption "Modify the standard shell options";
  };

  config = mkIf cfg.enable {
    environment.shells = with pkgs; [ fish ];
    users.defaultUserShell = pkgs.fish;
    programs.fish.enable = true;
  };
}