module Voyager
  module Holdings
    class Order
      attr_reader :orders, :current_issues
   
      # Order class initializing method
      # Populates instance variables from the mfhd:mfhdRecord node.
      #
      # * *Args*    :
      #   - +xml_node+ -> mfhd:mfhdRecord node
      #
      def initialize(xml_node)   

        # serials checkIn node
        serialsCheckIn = xml_node.at_css("mfhd|serialsCheckIn")
        @current_issues = parse_current_issues(serialsCheckIn)
        # purchase order line items node
        poLineItems = xml_node.at_css("mfhd|poLineItems")
        @orders = parse_order(poLineItems)

      end

      private
      
      # Parses the mfhd:serialsCheckIn node and creates an array of curent issues
      #
      # * *Args*    :
      #   - +serialsCheckIn+ -> mfhd:serialsCheckIn node
      # * *Returns* :
      #   - Array of messages for current issues
      #   - An empty array if there is no mfhd:serialsCheckIn node
      #
      def parse_current_issues(serialsCheckIn)
        
        return [] unless serialsCheckIn
        
        current_issues = []

        # unable to verify that there can be only one mfhd:recent node
        serialsCheckIn.css("mfhd|recent").each do |recent|
          # there can be more than one enumChron per recent node
          recent.css("mfhd|enumChron").each do |enumChron|
            current_issues << enumChron.content
          end
        end
        
        current_issues
        
      end

      # Parses the mfhd:poLineItems node and creates an array of order messages
      #
      # * *Args*    :
      #   - +poLineItems+ -> mfhd:poLineItems node
      # * *Returns* :
      #   - Array of message hashes for orders
      #       :status_code => status code
      #       :short_message => short version of the message
      #       :long_message => long version of the message
      #   - An empty array if there is no mfhd:poLineItems node
      #
      def parse_order(poLineItems)
        
        return [] unless poLineItems
        
        # generates and returns an array of order messages
        poLineItems.css("mfhd|lineItemStatus").collect { |lineItemStatus| generate_order_message(lineItemStatus) }
        
      end
      
      # Generate an order message from an mfhd:lineItemStatus node
      #
      # * *Args*    :
      #   - +lineItemStatus+ -> an mfhd:lineItemStatus node
      # * *Returns* :
      #   - An order message
      #
      def generate_order_message(lineItemStatus)
        
        status = lineItemStatus.at_css("mfhd|status").content
        date = lineItemStatus.at_css("mfhd|date").content
                
        # get parms for the message being processed
        parms = ORDER_STATUS_CODES[status]
      
        raise "Status code not found in config/order_status_codes.yml" unless parms
    
        short_message = parms['short_message'].gsub('%DATE',date)
        long_message = parms['long_message'].gsub('%DATE',date)

        { :status_code => status, :short_message => short_message, :long_message => long_message }

      end

    end
  end   
end