Improve selection of name to display in data browser

If the user is logged in then consider all their preferred
languages rather than just the UI language, and use the full
locale matching algorithm instead of just checking parents.

Fixes #2636

app/helpers/browse_helper.rb

@@ -11,9 +11,21 @@ module BrowseHelper
     # don't look at object tags if redacted, so as to avoid giving
     # away redacted version tag information.
     unless object.redacted?
-      locale = I18n.locale.to_s
+      available_locales = Locale::List.new(name_locales(object))
 
-      locale = locale.sub(/-[^-]+/, "") while locale =~ /-[^-]+/ && !object.tags.include?("name:#{I18n.locale}")
+      Rails.logger.info "available_locales = #{available_locales.map(&:to_s)}"
+
+      preferred_locales = if current_user
+                            current_user.preferred_languages
+                          else
+                            Locale.new(I18n.locale).candidates
+                          end
+
+      Rails.logger.info "preferred_locales = #{preferred_locales.expand.map(&:to_s)}"
+
+      locale = available_locales.preferred(preferred_locales)
+
+      Rails.logger.info "locale = #{locale}"
 
       if object.tags.include? "name:#{locale}"
         name = t "printable_name.with_name_html", :name => content_tag(:bdi, object.tags["name:#{locale}"].to_s), :id => content_tag(:bdi, name)
@@ -71,4 +83,8 @@ module BrowseHelper
   def icon_tags(object)
     object.tags.find_all { |k, _v| ICON_TAGS.include? k }.sort
   end
+
+  def name_locales(object)
+    object.tags.keys.map { |k| Regexp.last_match(1) if k =~ /^name:(.*)$/ }.flatten
+  end
 end