module ActiveAdmin::ResourceController::PolymorphicRoutes

def map_named_resources_for(record_or_hash_or_array)
  return record_or_hash_or_array unless record_or_hash_or_array.is_a?(Array)
  record_or_hash_or_array.map { |record| to_named_resource(record) }
end

def polymorphic_path(record_or_hash_or_array, options = {})
  super(map_named_resources_for(record_or_hash_or_array), options)
end

def polymorphic_url(record_or_hash_or_array, options = {})
  super(map_named_resources_for(record_or_hash_or_array), options)
end

def to_named_resource(record)
  if record.is_a?(resource_class)
    return ActiveAdmin::Model.new(active_admin_config, record)
  end
  belongs_to_resource = active_admin_config.belongs_to_config.try(:resource)
  if belongs_to_resource && record.is_a?(belongs_to_resource.resource_class)
    return ActiveAdmin::Model.new(belongs_to_resource, record)
  end
  record
end