Use fallbacks for OCI resource names

This uses the fallbacks for OCI translations. For example, if a
local chapter doesn't have an explicitly translated name, it will
use a template for osm-lc resources and fill in the appropriate
translated community name.

Fixes #3814

lib/osm_community_index.rb

@@ -14,9 +14,7 @@ module OsmCommunityIndex
         id = community.id
 
         strings = community_locale_yaml[id] || {}
-        # if the name isn't defined then fall back on community,
+        strings["name"] = resolve_name(community, community_locale_yaml)
-        # as per discussion here: https://github.com/osmlab/osm-community-index/issues/483
-        strings["name"] = strings["name"] || community.strings["name"] || community.strings["community"]
 
         obj.deep_merge!("osm_community_index" => { "communities" => { id => strings } })
       end
@@ -24,4 +22,23 @@ module OsmCommunityIndex
       I18n.backend.store_translations locale_rails, data
     end
   end
+
+  def self.resolve_name(community, community_locale_yaml)
+    # If theres an explicitly translated name then use that
+    translated_name = community_locale_yaml.dig(community.id, "name")
+    return translated_name if translated_name
+
+    # If not, then look up the default translated name for this type of community, and interpolate the template
+    template = community_locale_yaml.dig("_defaults", community.type, "name")
+    community_name = community_locale_yaml.dig("_communities", community.strings["communityID"])
+    # Change the `{community}` placeholder to `%{community}` and use Ruby's Kernel.format to fill it in.
+    translated_name = format(template.gsub("{", "%{"), { :community => community_name }) if template && community_name
+    return translated_name if translated_name
+
+    # Otherwise fall back to the (English-language) resource name
+    return community.strings["name"] if community.strings["name"]
+
+    # Finally use the (English-language) community name
+    community.strings["community"]
+  end
 end

test/lib/osm_community_index_test.rb

@@ -0,0 +1,39 @@
+require "test_helper"
+
+class CountryTest < ActiveSupport::TestCase
+  def test_community_name_fallback
+    # If there is no translations and no name for the chapter, use the community name
+    community = Community.new({ "id" => "foo-chapter", "type" => "osm-lc", "strings" => { "community" => "Community Name" } })
+    community_locale_yaml = {}
+
+    name = OsmCommunityIndex.resolve_name(community, community_locale_yaml)
+    assert_equal("Community Name", name)
+  end
+
+  def test_resource_name_fallback
+    # If there is a name for the chapter, prefer that to the community name
+    community = Community.new({ "id" => "foo-chapter", "type" => "osm-lc", "strings" => { "community" => "Community Name", "name" => "Chapter Name" } })
+    community_locale_yaml = {}
+
+    name = OsmCommunityIndex.resolve_name(community, community_locale_yaml)
+    assert_equal("Chapter Name", name)
+  end
+
+  def test_i18n_explicit_name
+    # If there is an explicitly translated name for the chapter, use that
+    community = Community.new({ "id" => "foo-chapter", "type" => "osm-lc", "strings" => { "community" => "Community Name", "name" => "Chapter Name" } })
+    community_locale_yaml = { "foo-chapter" => { "name" => "Translated Chapter Name" } }
+
+    name = OsmCommunityIndex.resolve_name(community, community_locale_yaml)
+    assert_equal("Translated Chapter Name", name)
+  end
+
+  def test_i18n_fallback_name
+    # If there's no explicitly translated name for the chapter, use the default name and interpolate the community name if required.
+    community = Community.new({ "id" => "foo-chapter", "type" => "osm-lc", "strings" => { "community" => "Community Name", "communityID" => "communityname" } })
+    community_locale_yaml = { "_communities" => { "communityname" => "Translated Community" }, "_defaults" => { "osm-lc" => { "name" => "{community} Chapter" } } }
+
+    name = OsmCommunityIndex.resolve_name(community, community_locale_yaml)
+    assert_equal("Translated Community Chapter", name)
+  end
+end

test/system/view_communities_test.rb

@@ -16,7 +16,7 @@ class ViewCommunitiesTest < ApplicationSystemTestCase
     click_on "Update Preferences"
 
     visit "/communities"
-    assert_link "OpenStreetMap US", :href => "https://www.openstreetmap.us/"
+    assert_link "OpenStreetMap États-Unis", :href => "https://www.openstreetmap.us/"
     assert_link "Chapitre local OpenStreetMap Belgique", :href => "https://openstreetmap.be/"
   end
 end