module Exlibris
  module Aleph
    require 'marc'
    # ==Overview
    # Provides access to the Aleph Record REST API.
    class Record < Rest::Base
      attr_accessor :bib_library, :record_id

      def initialize(*args)
        super
      end

      # Returns a MARC::Record that contains the bib data
      # Every method call refreshes the data from the underlying API.
      # Raises an exception if the response is not valid XML or there are errors.
      def bib
        self.response = self.class.get("#{record_url}?view=full")
        raise_error_if("Error getting bib from Aleph REST APIs.") {
          (response.parsed_response["get_record"].nil? or response.parsed_response["get_record"]["record"].nil?)
        }
        MARC::XMLReader.new(StringIO.new(xml(xml: response.body).at_xpath("get-record/record").to_xml(xml_options).strip)).first
      end

      # Returns an array of items. Each item is represented as a Hash.
      # Every method call refreshes the data from the underlying API.
      # Raises an exception if the response is not valid XML or there are errors.
      def items
        # Since we're parsing xml, this will raise an error
        # if the response isn't xml.
        self.response = self.class.get("#{record_url}/items?view=full")
        raise_error_if("Error getting items from Aleph REST APIs.") {
          (response.parsed_response["get_item_list"].nil? or response.parsed_response["get_item_list"]["items"].nil?)
        }
        [response.parsed_response["get_item_list"]["items"]["item"]].flatten
      end

      # Returns an array of holdings. Each holding is represented as a MARC::Record.
      # Every method call refreshes the data from the underlying API.
      # Raises an exception if there are errors.
      def holdings
        self.response = self.class.get("#{record_url}/holdings?view=full")
        raise_error_if("Error getting holdings from Aleph REST APIs.") {
          (response.parsed_response["get_hol_list"].nil? or response.parsed_response["get_hol_list"]["holdings"].nil?)
        }
        xml(xml: response.body).xpath("get-hol-list/holdings/holding").collect{ |holding|
          # Change the tag name to record so that the MARC::XMLReader can parse it.
          holding.name = "record"
          MARC::XMLReader.new(StringIO.new(holding.to_xml(xml_options).strip)).first
        }
      end

      def record_url
        @record_url ||= "#{rest_url}/record/#{bib_library}#{record_id}"
      end
      private :record_url
    end
  end
end