{
  description = "Declaratively update your data.";
  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
  outputs = { self, nixpkgs, ... }: let
    system = "x86_64-linux";
    pkgs = import nixpkgs { inherit system; };
    package = pkgs.stdenv.mkDerivation rec {
      pname = "fooud";
      version = "1.0";

      src = ./.;
      deps = pkgs.callPackage ./build.zig.zon.nix {};
      nativeBuildInputs = [ pkgs.zig.hook pkgs.libgit2 pkgs.gpgme ];
      zigBuildFlags = [
        "--system" "${deps}"
        "-Doptimize=Debug"
      ];
    };
  in {
    lib = builtins.import ./lib.nix { pkgs = pkgs; };
    nixosModules = rec {
      fooud = { pkgs, lib, config, inputs, ... }: {
        options.programs.fooud.enable = lib.mkEnableOption ("fooud")
          // { default = true; };
        config = lib.mkIf config.programs.fooud.enable {
          environment.systemPackages = [
            pkgs.libgit2
            pkgs.gpgme
            pkgs.nix
            package
          ];
        };
      };
      default = fooud;
    };
    packages.${system} = rec { default = package; fooud = default; };

    checks.${system}.build = let
      package = self.packages.${system}.default;
    in pkgs.runCommand "fooud-build" { buildInputs = [
        pkgs.git
        pkgs.nix
      ]; } ''
        mkdir repo
        git -C repo init > /dev/null 2>&1
        echo "hi" > repo/README.md
        git -C repo config user.email "you@example.com" > /dev/null 2>&1
        git -C repo config user.name "Your Name" > /dev/null 2>&1
        git -C repo add . > /dev/null 2>&1
        git -C repo commit -m "initial commit" > /dev/null 2>&1

        # this check won't succeed until I find a way to run a chroot store
        ${package}/bin/fooud --git repo --dest test
        '';
  };
}