module Scrivito
  class CmsRestApi
    class WidgetExtractor
      # Extract widgets from a given attribute tree
      # first return param: a flat hash of widget_like => updated widget attributes
      # second return param: the updated attributes
      def self.call(attributes, obj=nil)
        new(obj).extract_widgets(attributes)
      end

      def initialize(obj)
        @obj = obj
      end

      def extract_widgets(attributes)
        @extracted_widgets = {}
        updated_attributes = attributes.dup
        widget_pool = updated_attributes.delete(:_widget_pool)
        extract_widgets_from_pool(widget_pool) if widget_pool
        extract_widgets_from_attributes(updated_attributes)

        Extraction.new(extracted_widgets, updated_attributes)
      end

      private

      attr_reader :obj
      attr_reader :extracted_widgets

      def extract_widgets_from_pool(widget_pool)
        widget_pool.each do |widget, widget_properties|
          extracted_widgets[widget.id] = [widget, widget_properties]
          extract_widgets_from_attributes(widget_properties)
        end
      end

      def extract_widgets_from_attributes(attributes)
        attributes.each do |attribute_name, value|
          if value.is_a?(Array) && value.all? { |w| w.is_a?(BasicWidget) }
            value.each do |widget|
              unless widget.persisted?
                widget_attributes = widget.attach_to_obj(obj)
                extracted_widgets[widget.id] = [widget, widget_attributes]
                extract_widgets_from_attributes(widget_attributes)
              end
            end
          end
        end
      end

      class Extraction
        attr_reader :widget_pool_attributes, :attributes

        def initialize(widget_pool_attributes, attributes)
          @widget_pool_attributes = widget_pool_attributes
          @attributes = attributes
        end

        def notify_persisted(obj)
          widget_pool_attributes.each_value do |(widget, attributes)|
            if attributes.present?
              widget.notify_persisted(obj)
            end
          end
        end
      end
    end
  end
end