Refactor modules style

nixosModules/services/graphics/display_manager/default.nix

@@ -0,0 +1,23 @@
+{ config, pkgs, lib, ... }:
+
+{
+  options = {
+    tuigreet.enable = lib.mkEnableOption "enables tuigreet with greetd";
+  };
+
+  config = lib.mkIf config.tuigreet.enable {
+    services.greetd = {
+      enable = true;
+      package = pkgs.greetd.tuigreet;
+      settings = {
+        terminal = {
+          vt = 2;
+        };
+        default_session = lib.mkIf config.hyprland.enable {
+          command = "${pkgs.greetd.tuigreet}/bin/tuigreet --time --cmd Hyprland";
+          user = config.user.name;
+        };
+      };
+    };
+  };
+}