transformer.rb

class Transformer

  def initialize(configuration)
    @configuration = configuration
    @enrichment_fields = @configuration.reduce(Array.new) do |fields, (key, entry)|
      fields << entry[:field] if entry.is_a?(Hash) && entry[:field]
      fields
    end
  end


  def to_ingest_document(record)
    builder = Nokogiri::XML::Builder.new do |document|
      document.bibRecord do
        document.bib do |bib|
          bib.owningInstitutionId(@configuration[:institution_code])
          bib.content do
            bib.collection(xmlns: "http://www.loc.gov/MARC21/slim") do |marc|
              marc.parent << Nokogiri::XML(self.bib_without_enhancements(record).to_xml.to_s).at("record")
            end
          end # bibRecord/bib/content
        end # bibRecord/bib

        document.holdings do
          record.fields(@configuration[:locations][:field]).each do |location|
            holding_statements = record.fields(@configuration[:summary_statements][:field]).select {|s| s["8"] == location["8"]}

            document.holding do |holding|
              holding.owningInstitutionHoldingsId(location["8"])
              holding.content do
                holding.collection(xmlns: "http://www.loc.gov/MARC21/slim") do |marc|
                  marc.record do
                    marc.datafield(tag: "852", ind1: location.indicator1, ind2: location.indicator2) do
                      @configuration[:locations][:subfields].each do |sf_code|
                        marc.subfield(location[sf_code] ? location[sf_code] : "", code: sf_code)
                      end
                    end # bibRecord/holdings/holding/content/collection/record/datafield[tag="852"]

                    holding_statements.each do |stmt|
                      marc.datafield(tag: "866", ind1: stmt.indicator1, ind2: stmt.indicator2) do
                        @configuration[:summary_statements][:subfields].each do |sf_code|
                          marc.subfield(stmt[sf_code] ? stmt[sf_code] : "", code: sf_code)
                        end
                      end # holding_statements.each
                    end # bibRecord/holdings/holding/content/collection/record/datafield[tag="866"]
                  end # bibRecord/holdings/holding/content/collection/record
                end # bibRecord/holdings/holding/content/collection
              end # bibRecord/holdings/holding/content

              document.items do
                holding_items = record.fields(@configuration[:item_enrichment][:field]).select {|i| i["0"] == location["8"]}
                document.content do |items|
                  items.collection(xmlns: "http://www.loc.gov/MARC21/slim") do |marc|
                    holding_items.each do |item|
                      marc.record do
                        marc.datafield(tag: "876", ind1: " ", ind2: " ") do
                          item_config = @configuration[:item_enrichment]

                          # Required fields: must include and use a blank value
                          marc.subfield(item[item_config[:pid_sf]] ? item[item_config[:pid_sf]] : "", code: "a")
                          # Use Restrictions: Field must be present. Defaulting to blank value, which implies no restrictions.
                          # TODO: how will the BTAA determine use restrictions?
                          marc.subfield("", code: "h")
                          marc.subfield(item[item_config[:status_sf]] ? item[item_config[:status_sf]] : "", code: "j")
                          marc.subfield(location["b"], code: "k")
                          marc.subfield(item[item_config[:barcode_sf]] ? item[item_config[:barcode_sf]] : "", code: "p")
                          # TODO: what are the BTAA values for this code?
                          marc.subfield("BTAA", code: "l")

                          # Optional fields: do not require a blank value
                          marc.subfield(item[item_config[:copy_id_sf]], code: "t")     if item[item_config[:copy_id_sf]]
                          marc.subfield(item[item_config[:description_sf]], code: "3") if item[item_config[:description_sf]]
                        end # bibRecord/holdings/holding/content/items/content/collection/record/datafield[tag="876"]

                        marc.datafield(tag: "900", ind1: " ", ind2: " ") do
                          # TODO: need a way to determine whether to use values Open, Shared or Private
                          # for the Collection Group Designation (CGD)
                          marc.subfield("Shared", code: "a")
                          # TODO: what are the BTAA values for this code?
                          marc.subfield(@configuration[:institution_code], code: "b")
                        end # bibRecord/holdings/holding/content/items/content/collection/record/datafield[tag="900"]
                      end # bibRecord/holdings/holding/content/items/content/collection/record
                    end # holding_items.each
                  end # bibRecord/holdings/holding/content/items/content/collection
                end # bibRecord/holdings/holding/content/items/content
              end # bibRecord/holdings/holding/content/items
            end # bibRecord/holdings/holding
          end # @locations.each
        end # bibRecord/holdings
      end # bibRecord
    end # builder

    builder.doc
  end


  private


  def bib_without_enhancements(record)
    cloned_rec = MARC::Record.new
    cloned_rec.leader = record.leader
    record.fields.each do |field|
      cloned_rec << field unless @enrichment_fields.include?(field.tag)
    end
    cloned_rec
  end

end