nixos/cardboard: init

Copy-inspired from river.

nixos/modules/module-list.nix

@@ -268,6 +268,7 @@
   ./programs/usbtop.nix
   ./programs/vim.nix
   ./programs/wavemon.nix
+  ./programs/wayland/cardboard.nix
   ./programs/wayland/river.nix
   ./programs/wayland/sway.nix
   ./programs/wayland/waybar.nix

nixos/modules/programs/wayland/cardboard.nix

@@ -0,0 +1,31 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.programs.cardboard;
+in
+{
+  meta.maintainers = with lib.maintainers; [ AndersonTorres ];
+
+  options.programs.cardboard = {
+    enable = lib.mkEnableOption (lib.mdDoc "cardboard");
+
+    package = lib.mkOption {
+      type = with lib.types; nullOr package;
+      default = pkgs.cardboard;
+      defaultText = lib.literalExpression "pkgs.cardboard";
+      description = lib.mdDoc ''
+        cardboard package to use.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable (lib.mkMerge [
+    {
+      environment.systemPackages = [ cfg.package ];
+
+      # To make a cardboard session available for certain DMs like SDDM
+      services.xserver.displayManager.sessionPackages = [ cfg.package ];
+    }
+    (import ./wayland-session.nix { inherit lib pkgs; })
+  ]);
+}