enable declarative flatpak

configuration.nix

@@ -127,6 +127,16 @@ in
   # xdg.portal.extraPortals = [ pkgs.xdg-desktop-portal-kde ];
   xdg.portal.extraPortals = [ pkgs.xdg-desktop-portal-gtk ];
 
+  services.flatpak.packages = [
+    "com.discordapp.Discord"
+    "com.spotify.Client"
+    "com.visualstudio.code"
+    "it.mijorus.gearlever"
+    "org.libreoffice.LibreOffice"
+    "net.davidotek.pupgui2" # Proton-Up Qt
+    "io.github.prateekmedia.appimagepool"
+  ];
+
   # Enable AppImage
   boot.binfmt.registrations.appimage = {
     wrapInterpreterInShell = false;

flake.lock

@@ -213,6 +213,21 @@
         "type": "github"
       }
     },
+    "nix-flatpak": {
+      "locked": {
+        "lastModified": 1706716715,
+        "narHash": "sha256-aoUh0585v3mMkqGV+aggvs9uZQdZWSqMEGGVUT1jX38=",
+        "owner": "gmodena",
+        "repo": "nix-flatpak",
+        "rev": "30f6cb66a1be2a350b08b13e820122b0f3d4bd81",
+        "type": "github"
+      },
+      "original": {
+        "owner": "gmodena",
+        "repo": "nix-flatpak",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1706672657,
@@ -340,6 +355,7 @@
       "inputs": {
         "kde": "kde",
         "lanzaboote": "lanzaboote",
+        "nix-flatpak": "nix-flatpak",
         "nixpkgs": "nixpkgs_2"
       }
     },

flake.nix

@@ -4,6 +4,7 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     kde.url = "github:nix-community/kde2nix";
+    nix-flatpak.url = "github:gmodena/nix-flatpak";
 #    impermanence.url = "github:nix-community/impermanence";
     lanzaboote = {
       url = "github:nix-community/lanzaboote/v0.3.0";
@@ -12,14 +13,15 @@
   };
 
 #  outputs = { self, nixpkgs, impermanence, lanzaboote } @ inputs: {
-  outputs = { self, nixpkgs, lanzaboote, kde } @ inputs: {
+  outputs = { self, nixpkgs, lanzaboote, kde, nix-flatpak } @ inputs: {
     nixosConfigurations = {
       "matt-nixos" = nixpkgs.lib.nixosSystem {
         system = "x86_64-linux";
         modules = [
-#          inputs.impermanence.nixosModules.impermanence
-          inputs.lanzaboote.nixosModules.lanzaboote
-          inputs.kde.nixosModules.plasma6
+#          impermanence.nixosModules.impermanence
+          lanzaboote.nixosModules.lanzaboote
+          kde.nixosModules.plasma6
+          nix-flatpak.nixosModules.nix-flatpak
           ./configuration.nix
  #         ./impermanence.nix
         ];