nixos/dunst: init module

Co-authored-by: Sandro <sandro.jaeckel@gmail.com>

nixos/doc/manual/release-notes/rl-2605.section.md

@@ -36,6 +36,8 @@
 
 - [dsearch](https://github.com/AvengeMedia/danksearch), a fast filesystem search service with fuzzy matching. Available as [programs.dsearch](#opt-programs.dsearch.enable).
 
+- [Dunst](https://github.com/dunst-project/dunst), a lightweight and customizable notification daemon. Available as [services.dunst](#opt-services.dunst.enable).
+
 - [Ente Auth](https://ente.io/auth/), an open source 2FA authenticator, with end-to-end encrypted backups. Available as [programs.ente-auth](#opt-programs.ente-auth.enable).
 
 - [Dawarich](https://dawarich.app/), a self-hostable location history tracker. Available as [services.dawarich](#opt-services.dawarich.enable).

nixos/modules/module-list.nix

@@ -558,6 +558,7 @@
   ./services/desktops/bonsaid.nix
   ./services/desktops/cpupower-gui.nix
   ./services/desktops/dleyna.nix
+  ./services/desktops/dunst.nix
   ./services/desktops/espanso.nix
   ./services/desktops/flatpak.nix
   ./services/desktops/geoclue2.nix

nixos/modules/services/desktops/dunst.nix

@@ -0,0 +1,79 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+let
+  toml = pkgs.formats.toml { };
+  cfg = config.services.dunst;
+in
+{
+  options.services.dunst = {
+    enable = lib.mkEnableOption "Dunst notification daemon";
+
+    package = lib.mkPackageOption pkgs "dunst" { } // {
+      apply =
+        p:
+        p.override {
+          withX11 = cfg.enableX11;
+          withWayland = cfg.enableWayland;
+        };
+    };
+
+    settings = lib.mkOption {
+      type = toml.type;
+      default = { };
+      description = "Dunst configuration, see dunst(5)";
+      example = lib.literalExpression ''
+        {
+          global = {
+            width = 300;
+            height = 300;
+            offset = "30x50";
+            origin = "top-right";
+            transparency = 10;
+            frame_color = "#eceff1";
+            font = "Droid Sans 9";
+          };
+
+          urgency_normal = {
+            background = "#37474f";
+            foreground = "#eceff1";
+            timeout = 10;
+          };
+        };
+      '';
+    };
+
+    enableX11 = lib.mkOption {
+      type = lib.types.bool;
+      default = true;
+      description = "Whether to enable X11 support.";
+    };
+
+    enableWayland = lib.mkOption {
+      type = lib.types.bool;
+      default = true;
+      description = "Whether to enable Wayland support.";
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = cfg.enableX11 || cfg.enableWayland;
+        message = "Dunst must be built with at least either X11 support or Wayland support";
+      }
+    ];
+
+    environment = {
+      systemPackages = [ cfg.package ];
+      etc."xdg/dunst/dunstrc".source = toml.generate "dunstrc" cfg.settings;
+    };
+
+    services.dbus.packages = [ cfg.package ];
+  };
+
+  meta.maintainers = with lib.maintainers; [ nyukuru ];
+}