class ActiveModelSerializers::Adapter::Attributes

def cache_attributes
  return if @cached_attributes.present?
  @cached_attributes = ActiveModel::Serializer.cache_read_multi(serializer, self, @include_tree)
end

def initialize(serializer, options = {})
  super
  @include_tree = ActiveModel::Serializer::IncludeTree.from_include_args(options[:include] || '*')
  @cached_attributes = options[:cache_attributes] || {}
end

def relationship_value_for(association, options)
  return association.options[:virtual_value] if association.options[:virtual_value]
  return unless association.serializer && association.serializer.object
  opts = instance_options.merge(include: @include_tree[association.key])
  relationship_value = Attributes.new(association.serializer, opts).serializable_hash(options)
  if association.options[:polymorphic] && relationship_value
    polymorphic_type = association.serializer.object.class.name.underscore
    relationship_value = { type: polymorphic_type, polymorphic_type.to_sym => relationship_value }
  end
  relationship_value
end

def resource_object_for(options)
  if serializer.class.cache_enabled?
    @cached_attributes.fetch(serializer.cache_key(self)) do
      serializer.cached_fields(options[:fields], self)
    end
  else
    serializer.cached_fields(options[:fields], self)
  end
end

def resource_relationships(options)
  relationships = {}
  serializer.associations(@include_tree).each do |association|
    relationships[association.key] ||= relationship_value_for(association, options)
  end
  relationships
end

def serializable_hash(options = nil)
  options = serialization_options(options)
  if serializer.respond_to?(:each)
    serializable_hash_for_collection(options)
  else
    serializable_hash_for_single_resource(options)
  end
end

def serializable_hash_for_collection(options)
  cache_attributes
  serializer.map { |s| Attributes.new(s, instance_options).serializable_hash(options) }
end

def serializable_hash_for_single_resource(options)
  resource = resource_object_for(options)
  relationships = resource_relationships(options)
  resource.merge(relationships)
end