i2069: Add a new field for specific languages on the Show page

Gemfile

@@ -91,4 +91,4 @@ end
 
 gem "omniauth-rails_csrf_protection"
 
-gem "human_languages", "~> 0.6.0"
+gem "human_languages", "~> 0.7"

Gemfile.lock

@@ -267,7 +267,7 @@ GEM
       mini_mime (>= 1.0.0)
       multi_xml (>= 0.5.2)
     httpclient (2.8.3)
-    human_languages (0.6.0)
+    human_languages (0.7.0)
     i18n (1.12.0)
       concurrent-ruby (~> 1.0)
     iso-639 (0.3.5)
@@ -631,7 +631,7 @@ DEPENDENCIES
   gyoku (~> 1.0)
   high_voltage (~> 3.0)
   honeybadger (~> 4.0)
-  human_languages (~> 0.6.0)
+  human_languages (~> 0.7)
   jbuilder
   jquery-rails
   jquery-tablesorter (~> 1.21)

marc_to_solr/lib/language_extractor.rb

@@ -0,0 +1,61 @@
+# A class to pull out language information from
+# a MARC record
+class LanguageExtractor
+  def initialize(language_service, marc_record)
+    @marc_record = marc_record
+    @language_service = language_service
+  end
+
+  def specific_codes
+    codes = []
+    codes << fixed_field_code if fixed_field_code
+
+    if iso_041_fields.any?
+      codes.concat(iso_041_codes)
+    elsif all_041_fields.any?
+      codes.concat(all_041_codes)
+    end
+    codes.reject { |general_code| includes_more_specific_version?(codes, general_code) }
+  end
+
+  def specific_names
+    specific_codes.map { |code| @language_service.code_to_name(code) }
+                  .compact
+  end
+
+  private
+
+    def includes_more_specific_version?(codes, code_to_check)
+      codes.any? { |individual| @language_service.macrolanguage_codes(individual).include? code_to_check }
+    end
+
+    def iso_041_fields
+      all_041_fields.select { |field| field['2'] == 'iso639-3' }
+    end
+
+    def all_041_fields
+      @marc_record.fields('041')
+    end
+
+    def fixed_field_code
+      value = @marc_record['008']&.value
+      fixed_field_code = value ? value[35, 3] : nil
+    end
+
+    def iso_041_codes
+      return [] unless iso_041_fields.any?
+      extract_from_multiple_041s(iso_041_fields)
+    end
+
+    def all_041_codes
+      return [] unless all_041_fields.any?
+      extract_from_multiple_041s(all_041_fields)
+    end
+
+    def extract_from_multiple_041s(fields)
+      fields.map do |field|
+        field.subfields.select { |sf| %(a h).include? sf.code }
+             .map(&:value)
+      end.flatten
+    end
+end

marc_to_solr/lib/language_service.rb

@@ -12,12 +12,34 @@ def loc_to_iana(loc)
 
   def valid_language_code?(code)
     return false if code.blank?
-    Languages[code].present? || iso639_5_collective_languages['code'].include?(code)
+    Languages[code].present? || iso_639_5_include?(code)
+  end
+
+  def code_to_name(code)
+    Languages[code]&.name || iso_639_5_name(code)
+  end
+
+  def macrolanguage_codes(individual_language_code)
+    individual = Languages[individual_language_code]
+    if individual.respond_to? :macrolanguage
+      [individual&.macrolanguage&.alpha3_bibliographic.to_s, individual&.macrolanguage&.iso639_3.to_s].uniq
+    else
+      []
+    end
   end
 
   private
 
     def iso639_5_collective_languages
       @iso639_5_collective_languages ||= CSV.read(Rails.root.join('config', 'iso639-5.tsv'), headers: true, col_sep: "\t")
     end
+
+    def iso_639_5_include?(code)
+      iso639_5_collective_languages['code'].include?(code)
+    end
+
+    def iso_639_5_name(code)
+      return unless iso_639_5_include?(code)
+      iso639_5_collective_languages.find { |row| row['code'] == code }['Label (English)']
+    end
 end

marc_to_solr/lib/traject_config.rb

@@ -13,6 +13,7 @@
 require_relative './access_facet_builder'
 require_relative './augment_the_subject'
 require_relative './language_service'
+require_relative './language_extractor'
 require_relative './pul_solr_json_writer'
 require 'stringex'
 require 'library_stdnums'
@@ -727,6 +728,10 @@
 #    546 XX 3a
 to_field 'language_display', extract_marc('5463a')
 
+to_field 'language_name_display' do |record, accumulator|
+  accumulator.replace(LanguageExtractor.new(language_service, record).specific_names)
+end
+
 to_field 'language_facet', marc_languages
 
 to_field 'publication_place_facet', extract_marc('008[15-17]') do |_record, accumulator, _context|