{
  lib,
  self,
  stdenv,
  callPackage,
  zig,
  pkg-config,
  wayland,
  wayland-protocols,
  wayland-scanner,
  libxkbcommon,
  # Path to a replacement src/config.zig. dwm-style compile-time configuration:
  #   att_wm.override { configFile = ./my-config.zig; }
  # Deliberately not called `config`: callPackage would fill that from the
  # nixpkgs config set.
  configFile ? null,
}:

let
  deps = callPackage ./deps.nix { };
in
stdenv.mkDerivation {
  pname = "att_wm";
  version = "0.1.0";

  src = lib.cleanSource self;

  strictDeps = true;

  nativeBuildInputs = [
    zig
    pkg-config
    wayland-scanner
  ];

  buildInputs = [
    wayland
    wayland-protocols
    wayland-scanner
    libxkbcommon
  ];

  zigBuildFlags = [
    "--system"
    "${deps}"
    "-Dpie"
  ]
  ++ lib.optional (configFile != null) "-Dconfig=${configFile}";

  doCheck = true;

  # The check phase gets its own flag list, so it needs --system too; without
  # it `zig build test` tries to fetch the dependencies over the network and
  # fails in the sandbox.
  zigCheckFlags = [
    "--system"
    "${deps}"
  ];

  meta = {
    description = "A dwm-like window manager for the river Wayland compositor";
    longDescription = ''
      att_wm implements river-window-management-v1, providing dwm's window
      management model — tags, a master/stack layout, monocle and tabbed
      layouts — on top of river 0.4's non-monolithic compositor. Tag and window
      state is published over a JSON-lines unix socket for bars such as
      quickshell, and driven back the other way with the att_wmctl CLI.
    '';
    license = lib.licenses.gpl3Only;
    platforms = lib.platforms.linux;
    mainProgram = "att_wm";
  };
}