class ActiveAdmin::ResourceController::Decorators::Wrapper

def self.draper_collection_decorator
  ::Draper::CollectionDecorator
end

def self.draper_collection_decorator?(decorator)
  decorator && decorator <= draper_collection_decorator
rescue NameError
  false
end

def self.find_collection_decorator(decorator)
  if Dependency.draper?    '>= 1.3.0'
    decorator.collection_decorator_class
  elsif Dependency.draper? '>= 1.0.0'
    draper_collection_decorator
  else
    decorator
  end
end

def self.wrap(decorator)
  collection_decorator = find_collection_decorator(decorator)
  if draper_collection_decorator? collection_decorator
    name = "#{collection_decorator.name} of #{decorator} + ActiveAdmin"
    @cache[name] ||= wrap! collection_decorator, name
  else
    collection_decorator
  end
end

def self.wrap!(parent, name)
  ::Class.new parent do
    delegate :reorder, :page, :current_page, :total_pages, :limit_value,
             :total_count, :total_pages, :offset, :to_key, :group_values,
             :except, :find_each, :ransack
    define_singleton_method(:name) { name }
  end
end