dwm.service.nix

{ config, lib, pkgs, ... }:

with lib;

let

  cfg = config.services.xserver.windowManager.dwm;
  dwm =
    if cfg.configFile
    then (pkgs.dwm.overrideAttrs (old: { postPatch = "cp ${cfg.configFile} config.h"; }))
    else pkgs.dwm;

in

{

  ###### interface

  options = {
    services.xserver.windowManager.dwm.enable = mkEnableOption "dwm";

    # TODO: what constructor to use?
    services.xserver.windowManager.dwm.configFile = "mkConfigFileOption?";

    # TODO: consider allowing an inline config as well
  };


  ###### implementation

  config = mkIf cfg.enable {

    services.xserver.windowManager.session = singleton
      { name = "dwm";
        start =
          ''
            dwm &
            waitPID=$!
          '';
      };

    environment.systemPackages = [ dwm ];
  };
}