nixos-config/modules/desktop/gnome/default.nix

#
#  Gnome configuration
#
#  flake.nix
#   ├─ ./hosts
#   │   └─ ./laptop
#   │       └─ default.nix
#   └─ ./modules
#       └─ ./desktop
#           └─ ./gnome
#               └─ default.nix *
#
{ config, lib, user, pkgs, jovian-nixos, ... }:

{
    imports = [ 
      (jovian-nixos + "/modules")
    ];

    jovian = {
        steam.enable = true;
        devices.steamdeck = {
            enable = true;
        };
    };

    hardware.pulseaudio.enable = lib.mkForce false;

    hardware.opengl = {
      enable = true;
      driSupport = true;
      driSupport32Bit = true;
    };

    environment.systemPackages = with pkgs; [
      gnome.gnome-terminal
      gnomeExtensions.dash-to-dock
      steamdeck-firmware
      rocm-opencl-icd
      rocm-opencl-runtime
      clinfo
    ];

    services = {
      xserver = {
        enable = false;
        desktopManager.gnome.enable = true;
        displayManager = {
          gdm.wayland = true;
        #  defaultSession = "steam-wayland";
          autoLogin.enable = true;
          autoLogin.user = "kabbone";
        };
      };
    };

    systemd.services.gamescope-switcher = {
      wantedBy = [ "graphical.target" ];
      serviceConfig = {
        User = 2000;
        PAMName = "login";
        WorkingDirectory = "~";
  
        TTYPath = "/dev/tty7";
        TTYReset = "yes";
        TTYVHangup = "yes";
        TTYVTDisallocate = "yes";
  
        StandardInput = "tty-fail";
        StandardOutput = "journal";
        StandardError = "journal";
  
        UtmpIdentifier = "tty7";
        UtmpMode = "user";
  
        Restart = "always";
      };
  
      script = ''
        set-session () {
          mkdir -p ~/.local/state
          >~/.local/state/steamos-session-select echo "$1"
        }
        consume-session () {
          if [[ -e ~/.local/state/steamos-session-select ]]; then
            cat ~/.local/state/steamos-session-select
            rm ~/.local/state/steamos-session-select
          else
            echo "gamescope"
          fi
        }
        while :; do
          session=$(consume-session)
          case "$session" in
            plasma)
              dbus-run-session -- gnome-shell --display-server --wayland
              ;;
            gamescope)
              steam-session
              ;;
          esac
        done
      '';
    };
}