module Martyr
  module Runtime
    class Element < HashWithIndifferentAccess
      include Martyr::Translations
      include Martyr::Runtime::ElementCommon

      # @attribute element_locator [ElementLocator] this is added to an element in the process of building it
      # @attribute helper_module [Module] this is kept for reference, although the element object should already extend it
      attr_accessor :element_locator, :helper_module

      attr_reader :facts
      delegate :empty?, to: :facts
      delegate :cube_name, to: :element_locator
      delegate :grain_level_ids, :grain_hash, to: :@coordinates

      # @param coordinates [Coordinates]
      # @param values_hash [Hash] of the structure level_id => value. Unlike `coordinates.grain_hash`, for query levels the
      #   value is the string value, not the primary key.
      # @param facts [Array<Fact>]
      def initialize(coordinates, values_hash, facts)
        @coordinates = coordinates
        @facts = facts
        merge! values_hash
      end

      # @param key [String] either metric id or level id
      def fetch(key)
        value = super(key)
        value.is_a?(FutureMetric) ? value.value : value
      end
      alias_method :[], :fetch

      def coordinates
        @coordinates.to_hash
      end

      def coordinates_object
        @coordinates
      end

      def locate(*args)
        element_locator.locate(grain_hash, *args)
      end

      # Loads all future values
      def load
        keys.each{|key| fetch(key)}
        self
      end

      def key_for(level_id)
        raise Query::Error.new("Error: `#{level_id}` must be included in the element grain") unless coordinates.keys.include?(level_id)
        facts.first.fact_key_for(level_id)
      end

      def record_for(level_id)
        raise Query::Error.new("Error: `#{level_id}` must be included in the element grain") unless coordinates.keys.include?(level_id)
        facts.first.record_for(level_id)
      end

      def has_metric_id?(metric_id)
        metric_ids.include? MetricIdStandardizer.new(cube_name).standardize(metric_id)
      end
    end
  end
end