{
  description = "systemd-networkd Web UI (Go + HTML/JS)";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
    flake-utils.url = "github:numtide/flake-utils";
  };

  outputs = { self, nixpkgs, flake-utils, ... }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs { inherit system; };
      in
      {
        # Kehitysympäristö
        devShells.default = pkgs.mkShell {
          buildInputs = with pkgs; [
            go_1_24
            gopls          # LSP-tuki
          ];

          shellHook = ''
            echo "Development shell for systemd-networkd Web UI"
            echo "Go version: $(go version)"
          '';
        };

        # Sovelluksen buildattava paketti
        packages.default = pkgs.buildGoModule {
          pname = "networkd-webui";
          version = "0.1.0";

          src = ./.;

          vendorHash = null; # täytetään `nix develop` -> `go mod vendor` -> `nix hash`
          subPackages = [ "." ];

          ldflags = [ "-s" "-w" ];
        };

        # Deploymenttiin tarkoitettu NixOS service module
        nixosModules.default = { config, pkgs, lib, ... }: {
          options.services.networkd-webui = {
            enable = lib.mkEnableOption "systemd-networkd Web UI";
            port = lib.mkOption {
              type = lib.types.port;
              default = 8080;
              description = "Port for the web UI.";
            };
          };

          config = lib.mkIf config.services.networkd-webui.enable {
            systemd.services.networkd-webui = {
              description = "systemd-networkd Web UI";
              after = [ "network.target" ];
              wantedBy = [ "multi-user.target" ];

              serviceConfig = {
                ExecStart = "${self.packages.${system}.default}/bin/networkd-webui -port ${toString config.services.networkd-webui.port}";
                Restart = "on-failure";
                DynamicUser = true;
                ProtectSystem = "strict";
                ProtectHome = true;
                NoNewPrivileges = true;
              };
            };
          };
        };
      });
}