module ActionSprout::Facebook
  class Response

    attr_reader :http_status, :parsed_response, :headers, :graph

    def initialize(http_status, parsed_response, headers, graph)
      @http_status = http_status
      @parsed_response = parsed_response
      @headers = headers
      # TODO: Do we really need `graph` here?, if we can remove it then
      # HTTPService would no longer need to depend on a graph.
      @graph = graph
    end

    def has_error?
      http_status >= 400
    end

    def app_rate_limited?
      app_usage.present?
    end

    def page_rate_limited?
      page_usage.present?
    end

    def app_call_count
      app_usage.dig('call_count')
    end

    def app_total_time
      app_usage.dig('total_time')
    end

    def app_total_cputime
      app_usage.dig('total_cputime')
    end

    def page_call_count
      page_usage.dig('call_count')
    end

    def page_total_time
      page_usage.dig('total_time')
    end

    def page_total_cputime
      page_usage.dig('total_cputime')
    end

    private

    def app_usage
      @_app_usage ||= parse_json_header 'x-app-usage'
    end

    def page_usage
      @_page_usage ||= parse_json_header 'x-page-usage'
    end

    def parse_json_header(key)
      headers[key] ? JSON.parse(headers[key]) : {}
    end

  end
end