alakra/ndfd-weather-forecast-client

require 'ndfd/dwml/location'
require 'ndfd/dwml/time_layout'
require 'ndfd/dwml/parameter_extractor'

module NDFD
  class DWML
    class DataExtractor
      attr_reader :output, :element

      def initialize(element)
        @element = element
        @locations = []
        @time_layouts = []
        @output = {}
      end

      def process
        extract_locations
        extract_time_layouts
        extract_parameters

        output
      end

      protected

      def extract_locations
        @locations = NDFD::DWML::Location.extract(element.xpath("location"))
      end

      def extract_time_layouts
        @time_layouts = NDFD::DWML::TimeLayout.extract(element.xpath("time-layout"))
      end

      def extract_parameters
        parameters = element.xpath("parameters")

        @output.merge!(
          :parameters => parameters.inject({}) do |memo, parameter|
            location = location_for_parameter(parameter)
            extractor = NDFD::DWML::ParameterExtractor.new(parameter, location, @time_layouts)
            memo.merge!(location.location_key => extractor.process)
            memo
          end
        )
      end

      def location_for_parameter(parameter)
        @locations.detect do |location|
          parameter.attributes["applicable-location"].text == location.location_key
        end
      end
    end
  end
end