Add actions to support books' editions.

lib/decentralised_book_index/metadata.ex

@@ -3,7 +3,21 @@ defmodule DecentralisedBookIndex.Metadata do
     otp_app: :decentralised_book_index
 
   resources do
-    resource DecentralisedBookIndex.Metadata.Book
+    resource DecentralisedBookIndex.Metadata.Book do
+      define :create_book,
+        action: :create,
+        args: [:title, :isbn, :description, {:optional, :book_editions_registry_id}]
+
+      define :add_book_to_related_editions_registry,
+        action: :add_book_to_related_editions_registry,
+        args: [:title, :isbn, :description, :related_book_id]
+
+      define :list_books, action: :read
+      define :get_book_by_id, args: [:id], action: :by_id
+      define :get_book_alternative_editions, args: [:book], action: :get_alternative_editions
+      define :update_book, action: :update
+      define :destroy_book, action: :destroy
+    end
 
     resource DecentralisedBookIndex.Metadata.Author do
       define :create_author,
@@ -31,6 +45,12 @@ defmodule DecentralisedBookIndex.Metadata do
       define :destroy_author_alias_registry, action: :destroy
     end
 
-    resource DecentralisedBookIndex.Metadata.BookEditionsRegistry
+    resource DecentralisedBookIndex.Metadata.BookEditionsRegistry do
+      define :create_book_editions_registry, action: :create
+      define :list_book_editions_registries, action: :read
+      define :get_book_editions_registry_by_id, args: [:id], action: :by_id
+      define :update_book_editions_registry, action: :update
+      define :destroy_book_editions_registry, action: :destroy
+    end
   end
 end

lib/decentralised_book_index/metadata/book.ex

@@ -4,13 +4,70 @@ defmodule DecentralisedBookIndex.Metadata.Book do
     domain: DecentralisedBookIndex.Metadata,
     data_layer: AshPostgres.DataLayer
 
+  require Ash.Query
+
   postgres do
     table "books"
     repo DecentralisedBookIndex.Repo
   end
 
   actions do
-    defaults [:read]
+    defaults [:read, :update, :destroy]
+
+    create :create do
+      primary? true
+      accept [:title, :isbn, :description, :book_editions_registry_id]
+
+      change fn changeset, _ ->
+        registry_id = Ash.Changeset.get_attribute(changeset, :book_editions_registry_id)
+
+        if registry_id == nil do
+          {:ok, registry} = DecentralisedBookIndex.Metadata.create_book_editions_registry()
+
+          Ash.Changeset.force_change_attribute(changeset, :book_editions_registry_id, registry.id)
+        else
+          changeset
+        end
+      end
+    end
+
+    create :add_book_to_related_editions_registry do
+      accept [:title, :isbn, :description]
+
+      argument :related_book_id, :uuid do
+        allow_nil? false
+      end
+
+      change fn changeset, context ->
+        related_book_id = changeset.arguments.related_book_id
+
+        if related_book_id == nil do
+          Ash.Changeset.add_error(changeset, :related_book_id, "Related book is empty")
+        else
+          {:ok, related_book} = DecentralisedBookIndex.Metadata.get_book_by_id(related_book_id)
+
+          Ash.Changeset.force_change_attribute(changeset, :book_editions_registry_id, related_book.book_editions_registry_id)
+        end
+      end
+    end
+
+    read :by_id do
+      argument :id, :uuid, allow_nil?: false
+      get? true
+      filter expr(id == ^arg(:id))
+    end
+
+    read :get_alternative_editions do
+      argument :book, :struct, allow_nil?: false
+
+      prepare fn query, context ->
+        book = query.arguments.book
+
+        DecentralisedBookIndex.Metadata.Book
+        |> Ash.Query.filter(book_editions_registry_id == ^book.book_editions_registry_id
+                            and id != ^book.id)
+      end
+    end
   end
 
   attributes do