Convert id attribute macro to Ash extension

lib/geo/geography/country.ex

@@ -2,10 +2,10 @@ defmodule Geo.Geography.Country do
   use Ash.Resource,
     otp_app: :geo,
     domain: Geo.Geography,
-    data_layer: AshPostgres.DataLayer
+    data_layer: AshPostgres.DataLayer,
+    extensions: [Geo.Resources.Attributes.Id]
 
   # === Attributes ===
-  use Geo.Resources.Attributes.Id
   use Geo.Resources.Attributes.Name, allow_nil?: false, unique?: true
   use Geo.Resources.Attributes.Slug, allow_nil?: false, unique?: true
   use Geo.Resources.Attributes.Timestamps

lib/geo/resources/attributes/id.ex

@@ -1,12 +1,32 @@
 defmodule Geo.Resources.Attributes.Id do
   @moduledoc """
+  An Ash extension that adds a UUID v7 primary key attribute to a resource.
   """
 
-  defmacro __using__(_opts) do
-    quote do
-      attributes do
-        uuid_v7_primary_key :id
-      end
+  use Spark.Dsl.Extension,
+    transformers: [
+      __MODULE__.Transformer
+    ]
+
+  defmodule Transformer do
+    @moduledoc false
+    use Spark.Dsl.Transformer
+
+    def before?(Ash.Resource.Transformers.BelongsToAttribute), do: true
+    def before?(_), do: false
+
+    def transform(dsl_state) do
+      attribute = %Ash.Resource.Attribute{
+        name: :id,
+        type: :uuid_v7,
+        allow_nil?: false,
+        writable?: false,
+        public?: true,
+        primary_key?: true,
+        default: &Ash.UUIDv7.generate/0
+      }
+
+      {:ok, Spark.Dsl.Transformer.add_entity(dsl_state, [:attributes], attribute)}
     end
   end
 end