{
  config,
  inputs,
  lib,
  pkgs,
  ...
}:
{
  options.my.shell = {
    type = lib.mkOption {
      type = lib.types.enum [
        "bash"
        "zsh"
      ];
      default = "bash";
      description = "The shell to use system-wide (bash or zsh)";
    };
    users = lib.mkOption {
      type = lib.types.either lib.types.str (lib.types.listOf lib.types.str);
      default = config.my.toggleUsers.shell;
      merge = inputs.self.lib.mergeUsersOption lib;
      description = "Users to configure shell for";
    };
  };
  config = {
    users.users = lib.mkMerge (
      map (user: {
        ${user}.shell = pkgs.${config.my.shell.type};
      }) (inputs.self.lib.normalizeUsers config.my.shell.users)
    );
    programs.zsh.enable = config.my.shell.type == "zsh";
  };
}