feat(home-manager): add gnomeShellTheme option for gtk (#161)

* feat(home-manager/gtk): add gnome option

Add an option to set the gtk theme as gnome shell's theme using the
user-theme gnome extension

* implemented feedbacks

* style(home-manager): format gtk module

---------

Co-authored-by: seth <getchoo@tuta.io>

modules/home-manager/gtk.nix

@@ -4,7 +4,7 @@
 , ...
 }:
 let
-  inherit (lib) ctp mkOption types;
+  inherit (lib) ctp mkOption mkEnableOption types;
   cfg = config.gtk.catppuccin;
   enable = cfg.enable && config.gtk.enable;
   # "dark" and "light" can be used alongside the regular accents
@@ -25,6 +25,7 @@ in
         default = [ "normal" ];
         description = "Catppuccin tweaks for gtk";
       };
+      gnomeShellTheme = mkEnableOption "Catppuccin gtk theme for GNOME Shell";
 
       cursor = ctp.mkCatppuccinOpt "gtk cursors"
       // {
@@ -34,7 +35,7 @@ in
 
   config = lib.mkIf enable {
     assertions = [
-      (lib.ctp.assertXdgEnabled "gtk")
+      (ctp.assertXdgEnabled "gtk")
     ];
 
     gtk = {
@@ -79,5 +80,25 @@ in
         "gtk-4.0/gtk.css".source = "${gtk4Dir}/gtk.css";
         "gtk-4.0/gtk-dark.css".source = "${gtk4Dir}/gtk-dark.css";
       };
+
+    home.packages = lib.mkIf cfg.gnomeShellTheme [ pkgs.gnomeExtensions.user-themes ];
+
+    dconf.settings = lib.mkIf cfg.gnomeShellTheme {
+      "org/gnome/shell" = {
+        disable-user-extensions = false;
+        enabled-extensions = [
+          "user-theme@gnome-shell-extensions.gcampax.github.com"
+        ];
+      };
+      "org/gnome/shell/extensions/user-theme" = {
+        name = config.gtk.theme.name;
+      };
+      "org/gnome/desktop/interface" = {
+        color-scheme =
+          if cfg.flavour == "latte"
+          then "default"
+          else "prefer-dark";
+      };
+    };
   };
 }