os/shell.nix

{ pkgs ? import <nixpkgs> { } }:
let
  configs = "${toString ./.}#nixosConfigurations";

  buildIso = pkgs.writeShellScriptBin "build-iso" ''
    nix build ${configs}.niximg.config.system.build.isoImage $@
  '';
in pkgs.mkShell {
  nativeBuildInputs = with pkgs; [ git git-crypt nixFlakes buildIso ];

  shellHook = ''
    mkdir -p secrets
  '';

  NIX_CONF_DIR = let
    current = pkgs.lib.optionalString (builtins.pathExists /etc/nix/nix.conf)
      (builtins.readFile /etc/nix/nix.conf);

    nixConf = pkgs.writeTextDir "opt/nix.conf" ''
      ${current}
      experimental-features = nix-command flakes ca-references
    '';
  in "${nixConf}/opt";
}