From f2f4990779ddbe27a2e51be851fb72240c54b8e0 Mon Sep 17 00:00:00 2001
From: KKlochko <KKlochko@protonmail.com>
Date: Fri, 7 Mar 2025 13:47:15 +0200
Subject: [PATCH] Update the create action for Author to set
 AuthorAliasRegistry.

---
 lib/decentralised_book_index/metadata.ex      |  2 +-
 .../metadata/author.ex                        | 19 +++++++++++++++++++
 .../metadata/author_test.exs                  | 18 ++++++++++++++++++
 3 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 test/decentralised_book_index/metadata/author_test.exs

diff --git a/lib/decentralised_book_index/metadata.ex b/lib/decentralised_book_index/metadata.ex
index c64ef4b..c5663b1 100644
--- a/lib/decentralised_book_index/metadata.ex
+++ b/lib/decentralised_book_index/metadata.ex
@@ -6,7 +6,7 @@ defmodule DecentralisedBookIndex.Metadata do
     resource DecentralisedBookIndex.Metadata.Book
 
     resource DecentralisedBookIndex.Metadata.Author do
-      define :create_author, action: :create, args: [:name, :description, :author_alias_registry_id]
+      define :create_author, action: :create, args: [:name, :description, {:optional, :author_alias_registry_id}]
       define :add_author_to_alias_registry, action: :add_author_to_alias_registry, args: [:author_alias_registry_id]
       define :list_authors, action: :read
       define :get_author_by_id, args: [:id], action: :by_id
diff --git a/lib/decentralised_book_index/metadata/author.ex b/lib/decentralised_book_index/metadata/author.ex
index 545c8b6..a880cae 100644
--- a/lib/decentralised_book_index/metadata/author.ex
+++ b/lib/decentralised_book_index/metadata/author.ex
@@ -20,6 +20,25 @@ defmodule DecentralisedBookIndex.Metadata.Author do
       primary? true
       accept [:name, :description, :author_alias_registry_id]
 
+      change fn changeset, _ ->
+        registry_id = Ash.Changeset.get_attribute(changeset, :author_alias_registry_id)
+
+        if registry_id == nil do
+          {:ok, registry} = DecentralisedBookIndex.Metadata.create_author_alias_registry()
+
+          Ash.Changeset.force_change_attribute(changeset, :author_alias_registry_id, registry.id)
+        else
+          changeset
+        end
+      end
+    end
+
+    read :by_id do
+      argument :id, :uuid, allow_nil?: false
+      get? true
+      filter expr(id == ^arg(:id))
+    end
+
     end
   end
 
diff --git a/test/decentralised_book_index/metadata/author_test.exs b/test/decentralised_book_index/metadata/author_test.exs
new file mode 100644
index 0000000..413a4ca
--- /dev/null
+++ b/test/decentralised_book_index/metadata/author_test.exs
@@ -0,0 +1,18 @@
+defmodule DecentralisedBookIndex.Metadata.AuthorTest do
+  use DecentralisedBookIndex.DataCase, async: true
+
+  alias DecentralisedBookIndex.Metadata
+
+  describe "authors and registries relationship" do
+    test "a new author get new registry by default" do
+      assert {:ok, author} = Metadata.create_author("Author", "An description")
+      assert author.author_alias_registry_id != nil
+    end
+
+    test "a new author belongs to a registry if specified" do
+      assert {:ok, registry} = Metadata.create_author_alias_registry()
+      assert {:ok, author} = Metadata.create_author("Author", "An description", registry.id)
+      assert author.author_alias_registry_id == registry.id
+    end
+  end
+end