{
  description = "Infinsweeper";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
  };

  outputs =
    { nixpkgs, ... }:
    let
      system = "x86_64-linux";
      pkgs = nixpkgs.legacyPackages.${system};

      ruby = pkgs.ruby.withPackages (
        p: with p; [
          sqlite3
          sequel
          rackup
          puma
          sinatra
        ]
      );

      app = pkgs.stdenv.mkDerivation {
        pname = "infinsweeper";
        version = "0.1.0";
        src = ./.;
        buildInputs = [ ruby ];
        installPhase = ''
          mkdir -p $out
          cp -r . $out/
        '';
      };

      server = pkgs.writeShellApplication {
        name = "infinsweeper";
        runtimeInputs = [ ruby ];
        text = ''
          set -euo pipefail
          data_dir="''${INFINSWEEPER_DATA_DIR:-/var/lib/infinsweeper}"
          DB="$data_dir/infinsweeper.db"
          mkdir -p "$data_dir"
          exec ruby ${app}/main.rb
        '';
      };
    in
    {
      packages.${system}.default = app;

      apps.${system}.default = {
        type = "app";
        program = "${server}/bin/infinsweeper";
      };

      devShells.${system}.default = pkgs.mkShell {
        packages = [
          ruby
          pkgs.sqlite
        ];
      };
    };
}