Add the author roles to the Book form.

lib/decentralised_book_index/metadata/author_role.ex

@@ -12,7 +12,7 @@ defmodule DecentralisedBookIndex.Metadata.AuthorRole do
   end
 
   actions do
-    defaults [:read, :update, :destroy]
+    defaults [:read, :destroy]
 
     create :create do
       primary? true
@@ -20,7 +20,8 @@ defmodule DecentralisedBookIndex.Metadata.AuthorRole do
       argument :author_id, :uuid
 
       change fn changeset, _ ->
-        author_id = changeset.arguments.author_id
+        author_id =
+          Map.get(changeset.arguments, :author_id, nil)
 
         if author_id != nil do
           {:ok, author} = DecentralisedBookIndex.Metadata.get_author_by_id(author_id)
@@ -37,6 +38,24 @@ defmodule DecentralisedBookIndex.Metadata.AuthorRole do
       get? true
       filter expr(id == ^arg(:id))
     end
+
+    update :update do
+      primary? true
+      accept [:order, :role]
+      argument :author_id, :uuid
+
+      change fn changeset, _ ->
+        author_id = changeset.arguments.author_id
+
+        if author_id != nil do
+          {:ok, author} = DecentralisedBookIndex.Metadata.get_author_by_id(author_id)
+
+          Ash.Changeset.force_change_attribute(changeset, :author_id, author.id)
+        else
+          changeset
+        end
+      end
+    end
   end
 
   attributes do