add nix module

flake.nix

@@ -16,67 +16,12 @@
       ...
     }@inputs:
     flake-parts.lib.mkFlake { inherit inputs; } {
+      imports = [ ./linux/nix ];
       systems = [
         "x86_64-linux"
         "aarch64-linux"
         "aarch64-darwin"
         "x86_64-darwin"
       ];
-
-      perSystem =
-        {
-          lib,
-          pkgs,
-          system,
-          ...
-        }:
-
-        {
-          _module.args.pkgs = import nixpkgs {
-            inherit system;
-            config = {
-              android_sdk.accept_license = true;
-              allowUnfree = true;
-            };
-          };
-
-          packages =
-            let
-              default = pkgs.callPackage ./linux/nix/pkg {
-                src = self;
-              };
-            in
-            {
-              inherit default;
-
-              flatpak = inputs.nix2flatpak.lib.${system}.mkFlatpak {
-                appName = "Nexus";
-                developer = "QuadRadical";
-                appId = "nexus.federated.nexus";
-                package = default;
-                runtime = "org.gnome.Platform/49";
-                permissions = {
-                  share = [ "network" ];
-                  sockets = [
-                    "pulseaudio"
-                    "fallback-x11"
-                    "wayland"
-                  ];
-
-                  talk-names = [
-                    "org.unifiedpush.Distributor.*"
-                    "org.freedesktop.Notifications"
-                  ];
-                  devices = [ "dri" ];
-                };
-              };
-
-              gomuks = pkgs.callPackage ./linux/nix/pkg/gomuks.nix {
-                src = self;
-              };
-            };
-
-          devShells.default = pkgs.callPackage ./linux/nix/devshell.nix { };
-        };
     };
 }

lib/controllers/unified_push.dart

@@ -28,7 +28,7 @@ class UnifiedPushController extends AsyncNotifier<bool> {
         dbusName: "nexus.federated.nexus.UnifiedPush",
         storage: UnifiedPushStorageSharedPreferences(),
         background: isInBackground,
-        shouldWriteService: false,
+        shouldWriteService: true,
       ),
       onNewEndpoint: (endpoint, instance) async {
         final pushKey = endpoint.pubKeySet!.pubKey;

linux/nexus.federated.nexus.UnifiedPush.service

@@ -0,0 +1,3 @@
+[D-BUS Service]
+Name=nexus.federated.nexus.UnifiedPush
+Exec=/usr/bin/env FLUTTER_HEADLESS=1 nexus

linux/nix/default.nix

@@ -0,0 +1,59 @@
+{ self, inputs, ... }: {
+
+  perSystem =
+    {
+      pkgs,
+      system,
+      lib,
+      ...
+    }:
+    {
+      _module.args.pkgs = import inputs.nixpkgs {
+        inherit system;
+        config = {
+          android_sdk.accept_license = true;
+          allowUnfree = true;
+        };
+      };
+
+      packages =
+        let
+          default = pkgs.callPackage ./pkg {
+            src = self;
+          };
+        in
+        {
+          inherit default;
+
+          flatpak = inputs.nix2flatpak.lib.${system}.mkFlatpak {
+            appName = "Nexus";
+            developer = "QuadRadical";
+            appId = "nexus.federated.nexus";
+            package = default;
+            runtime = "org.gnome.Platform/49";
+            permissions = {
+              share = [ "network" ];
+              sockets = [
+                "pulseaudio"
+                "fallback-x11"
+                "wayland"
+              ];
+
+              talk-names = [
+                "org.unifiedpush.Distributor.*"
+                "org.freedesktop.Notifications"
+              ];
+              devices = [ "dri" ];
+            };
+          };
+
+          gomuks = pkgs.callPackage ./pkg/gomuks.nix {
+            src = self;
+          };
+        };
+
+      devShells.default = pkgs.callPackage ./devshell.nix { };
+    };
+
+  flake.nixosModules.default = import ./module.nix self;
+}

linux/nix/module.nix

@@ -0,0 +1,55 @@
+self:
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}:
+
+let
+  inherit (lib)
+    mkIf
+    mkMerge
+    mkOption
+    mkEnableOption
+    mkPackageOption
+    types
+    ;
+
+  cfg = config.programs.nexus;
+in
+{
+  options.programs.nexus = {
+    enable = mkEnableOption "Nexus, a simple and user-friendly Matrix client";
+    package = mkPackageOption self.packages.${pkgs.stdenv.hostPlatform.system} "nexus" { };
+
+    enableNotifications = mkOption {
+      description = ''
+        Whether to enable push notifications support via UnifiedPush, installing
+        {manpage}`kunifiedpush` and registering its systemd and D-Bus units.
+      '';
+      type = types.bool;
+      default = false;
+      example = true;
+    };
+  };
+
+  config = mkIf cfg.enable (mkMerge [
+    {
+      environment.systemPackages = [ cfg.package ];
+    }
+    (mkIf cfg.enableNotifications {
+      environment.systemPackages = [
+        pkgs.kdePackages.kunifiedpush
+      ];
+
+      systemd.packages = [
+        pkgs.kdePackages.kunifiedpush
+      ];
+
+      services.dbus.packages = [
+        cfg.package
+      ];
+    })
+  ]);
+}

linux/nix/pkg/default.nix

@@ -37,6 +37,7 @@ flutter.buildFlutterApplication {
   postInstall = ''
     install -D assets/bundled/icon.svg $out/share/icons/hicolor/scalable/apps/nexus.svg
     install -Dm755 linux/nexus.federated.nexus.desktop -t $out/share/applications
+    install -Dm644 linux/*.service -t $out/share/dbus-1/services
     wrapProgram $out/bin/nexus \
       --suffix LD_LIBRARY_PATH : $out/app/nexus/lib
   '';