nix-config-v2/modules/desktop/default.nix

{
  config,
  lib,
  pkgs,
  ...
}: let
  cfg = config.desktop;

  defaultWaylandPackages = with pkgs; [
    brightnessctl
    cliphist
    foot
    grim
    libnotify
    mako
    networkmanagerapplet
    playerctl
    polkit_gnome
    pavucontrol
    rofi
    slurp
    waybar
    wl-clipboard
    xdg-utils
  ];

  defaultSwayPackages =
    defaultWaylandPackages
    ++ (with pkgs; [
      pulseaudio
      swayidle
      swaylock
      wmenu
    ]);

  resolvedDisplayManager =
    if cfg.displayManager != "auto"
    then cfg.displayManager
    else if cfg.gnome.enable
    then "gdm"
    else if cfg.xfce.enable
    then "lightdm"
    else "none";
in {
  options.desktop = {
    displayManager = lib.mkOption {
      type = lib.types.enum ["auto" "none" "gdm" "lightdm" "ly"];
      default = "auto";
      description = ''
        Display manager to enable. In auto mode, GDM is used when GNOME is
        enabled, LightDM is used when XFCE is enabled, and no display manager
        is enabled for compositor-only configurations.
      '';
    };

    gnome.enable = lib.mkEnableOption "the vanilla GNOME desktop environment";

    xfce.enable = lib.mkEnableOption "the vanilla XFCE desktop environment";

    sway = {
      enable = lib.mkEnableOption "the Sway Wayland compositor";

      extraPackages = lib.mkOption {
        type = with lib.types; listOf package;
        default = defaultSwayPackages;
        defaultText = lib.literalExpression ''
          with pkgs; [
            brightnessctl
            cliphist
            foot
            grim
            libnotify
            mako
            networkmanagerapplet
            playerctl
            polkit_gnome
            pulseaudio
            pavucontrol
            rofi
            slurp
            swayidle
            swaylock
            waybar
            wl-clipboard
            wmenu
            xdg-utils
          ]
        '';
        description = "Packages installed alongside Sway.";
      };
    };

    hyprland = {
      enable = lib.mkEnableOption "the Hyprland Wayland compositor";

      extraPackages = lib.mkOption {
        type = with lib.types; listOf package;
        default = defaultWaylandPackages;
        defaultText = lib.literalExpression ''
          with pkgs; [
            brightnessctl
            cliphist
            foot
            grim
            libnotify
            mako
            networkmanagerapplet
            playerctl
            polkit_gnome
            pavucontrol
            rofi
            slurp
            waybar
            wl-clipboard
            xdg-utils
          ]
        '';
        description = ''
          Packages installed alongside Hyprland. Hyprlock and Hypridle are
          enabled separately so their NixOS integration, including PAM, is
          configured as well.
        '';
      };
    };
  };

  config = lib.mkMerge [
    (lib.mkIf cfg.gnome.enable {
      services.desktopManager.gnome.enable = true;
    })

    (lib.mkIf cfg.xfce.enable {
      services.xserver = {
        enable = true;
        desktopManager.xfce.enable = true;
      };
    })

    (lib.mkIf cfg.sway.enable {
      programs.sway = {
        enable = true;
        wrapperFeatures.gtk = true;
        extraPackages = cfg.sway.extraPackages;
      };
    })

    (lib.mkIf cfg.hyprland.enable {
      programs = {
        hyprland.enable = true;
        hyprlock.enable = lib.mkDefault true;
      };

      environment.systemPackages = cfg.hyprland.extraPackages;
    })

    (lib.mkIf (resolvedDisplayManager == "gdm") {
      services.displayManager.gdm.enable = true;
    })

    (lib.mkIf (resolvedDisplayManager == "lightdm") {
      services.xserver = {
        enable = true;
        displayManager.lightdm.enable = true;
      };
    })

    (lib.mkIf (resolvedDisplayManager == "ly") {
      services.displayManager.ly.enable = true;
    })
  ];
}