module Parliament
  module Utils
    module Helpers
      class RoleGroupingHelper
        extend Parliament::Utils::Helpers::GroupingHelper
        # Finds Grom::Nodes that can be grouped and builds GroupingHelper::GroupedObject objects
        #
        # @return start_date [DateTime] Earliest start date
        # @return end_date [DateTime] Latest end date
        # @return nodes [Array] Array of Grom::Nodes
        # @return type [String] Type of all grouped Grom::Nodes
        class RoleGroupedObject
          attr_accessor :start_date, :end_date, :nodes, :type
        end

        # Creates new GroupingHelper::GroupedObject, for each set of Grom::Nodes that have been grouped (nodes)
        # Each instance of GroupingHelper::GroupedObject is assigned properties of start_date, end_date, nodes and type
        # Once object has been created, calls sort_grouped_nodes_by_date method to sort that object's nodes by date
        #
        # @param data_hash [Hash] Keys identify grouping, with each value being an array of grouped, ungrouped and unknown Grom::Nodes
        # @param key [String] Key identifies grouping of Grom::Nodes
        # @return [Array] with instances of GroupingHelper::GroupedObject
        def self.create_grouped_objects(data_hash, key)
          grouped = []

          grouped_object = RoleGroupingHelper::RoleGroupedObject.new
          grouped_object.nodes = data_hash[key]

          start_date = nil
          end_date = nil
          current_nodes = []

          grouped_object.nodes.each do |node|
            # Find nodes that represents current roles
            current_nodes << node if node.try(:end_date).nil? || node.end_date.nil?
            # Find earliest start date and latest end date
            start_date = node.start_date if start_date.nil? || node.start_date < start_date
            end_date = node.end_date if current_nodes.empty? && (end_date.nil? || node.end_date > end_date)
          end

          # Set properties of the object
          # TODO: Might need to adjust to allow for multiple roles roles and memberships of a committee
          grouped_object.type = grouped_object.nodes.first.type
          grouped_object.start_date = start_date
          grouped_object.end_date = current_nodes.empty? ? end_date : nil

          # Add sorted object to the array
          sort_grouped_nodes_by_date(grouped_object, current_nodes)
          grouped << grouped_object
        end

        # Sorts an array of grouped Grom::Nodes by end date, placing the most current Grom::Node at the start of the array
        #
        # @param grouped_object [Instance object] Instance of GroupingHelper::GroupedObject
        # @param current_node [Grom::Node] Grom::Node with no end date (representing current)
        # @return [Instance object] Returns the same instance, with nodes sorted by end date
        def self.sort_grouped_nodes_by_date(grouped_object, current_nodes)
          grouped_object.nodes -= current_nodes unless current_nodes.empty?
          grouped_object.nodes.sort_by!(&:end_date).reverse!
          grouped_object.nodes.unshift(current_nodes).flatten! unless current_nodes.empty?
        end
      end
    end
  end
end