Add a rake task to convert page trees into menus

Run this task to convert your current page trees into menus

    rake alchemy:convert:page_trees:to_menus

lib/tasks/alchemy/convert.rake

@@ -31,5 +31,44 @@ namespace :alchemy do
         puts "Done."
       end
     end
+
+    namespace :page_trees do
+      desc "Converts the page tree into a menu."
+      task to_menus: [:environment] do
+        if Alchemy::Node.roots.exists?
+          abort "\n⨯ There are already menus present in your database. Aborting!"
+        end
+
+        def convert_to_nodes(children, node:)
+          children.each do |page|
+            has_children = page.children.any?
+            next unless page.visible || has_children
+
+            new_node = node.children.create!(
+              name: page.visible? ? nil : page.name,
+              page: page.visible? ? page : nil,
+              language_id: page.language_id
+            )
+            print "."
+            if has_children
+              convert_to_nodes(page.children, node: new_node)
+            end
+          end
+        end
+
+        puts "\n- Converting page trees into menus. Hold tight, this may take a while!"
+        Alchemy::BaseRecord.transaction do
+          Alchemy::Language.all.each do |language|
+            locale = language.locale.presence || I18n.default_locale
+            menu_name = I18n.t('Main Navigation', scope: 'alchemy.menu_names', default: 'Main Navigation', locale: locale)
+            root_node = Alchemy::Node.create(language: language, name: menu_name)
+            language.pages.language_roots.each do |root_page|
+              convert_to_nodes(root_page.children, node: root_node)
+            end
+          end
+        end
+        puts "\n✓ Done."
+      end
+    end
   end
 end