{
  description = "Python env for HaFaS-Fumbling";

  inputs.nixpkgs.url = github:nixos/nixpkgs;

  outputs = { self, nixpkgs, ... }: let 
    pipPackages = ''
      pyhafas
    '';
    system = "x86_64-linux";
  in {
    devShells."${system}".default = let
      pkgs = import nixpkgs { inherit system; };
    in pkgs.mkShell {
      buildInputs = [
        pkgs.python312
        pkgs.python312Packages.pip
      ];
      shellHook = ''
        if [ ! -d ".venv" ]; then
          python -m venv .venv
        fi
        source .venv/bin/activate
        pip install ${pipPackages}
        exec zsh || true
      '';
    };
  };
}