Add an action to add author to relative author's alias registry.

lib/decentralised_book_index/metadata.ex

@@ -7,7 +7,7 @@ defmodule DecentralisedBookIndex.Metadata do
 
     resource DecentralisedBookIndex.Metadata.Author do
       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 :add_author_to_related_alias_registry, action: :add_author_to_related_alias_registry, args: [:name, :description, :related_author_id]
       define :list_authors, action: :read
       define :get_author_by_id, args: [:id], action: :by_id
       define :update_author, action: :update

lib/decentralised_book_index/metadata/author.ex

@@ -12,10 +12,6 @@ defmodule DecentralisedBookIndex.Metadata.Author do
   actions do
     defaults [:read, :update, :destroy]
 
-    update :add_author_to_alias_registry do
-      accept [:author_alias_registry_id]
-    end
-
     create :create do
       primary? true
       accept [:name, :description, :author_alias_registry_id]
@@ -33,13 +29,31 @@ defmodule DecentralisedBookIndex.Metadata.Author do
       end
     end
 
+    create :add_author_to_related_alias_registry do
+      accept [:name, :description]
+
+      argument :related_author_id, :uuid do
+        allow_nil? false
+      end
+
+      change fn changeset, context ->
+        related_author_id = changeset.arguments.related_author_id
+
+        if related_author_id == nil do
+          Ash.Changeset.add_error(changeset, :related_author_id, "Related author is empty")
+        else
+          {:ok, related_author} = DecentralisedBookIndex.Metadata.get_author_by_id(related_author_id)
+
+          Ash.Changeset.force_change_attribute(changeset, :author_alias_registry_id, related_author.author_alias_registry_id)
+        end
+      end
+    end
+
     read :by_id do
       argument :id, :uuid, allow_nil?: false
       get? true
       filter expr(id == ^arg(:id))
     end
-
-    end
   end
 
   attributes do

test/decentralised_book_index/metadata/author_test.exs

@@ -14,5 +14,19 @@ defmodule DecentralisedBookIndex.Metadata.AuthorTest do
       assert {:ok, author} = Metadata.create_author("Author", "An description", registry.id)
       assert author.author_alias_registry_id == registry.id
     end
+
+    test "a new author to a registry via a related author record" do
+      {:ok, related_author}  = Metadata.create_author("Author",  "An description")
+
+      assert {:ok, author} =
+        Metadata.add_author_to_related_alias_registry("Author2", "An description2", related_author.id)
+
+      assert related_author.author_alias_registry_id == author.author_alias_registry_id
+    end
+
+    test "a new author to a registry via a empty related author record" do
+      assert {:error, _} =
+        Metadata.add_author_to_related_alias_registry("Author2", "An description2", nil)
+    end
   end
 end