#398

backend/app/services/preview/known_site_extractor.rb

@@ -1,7 +1,16 @@
 module Preview
   class KnownSiteExtractor
     def self.thumbnail_url(uri)
-      youtube_thumbnail(uri) || niconico_thumbnail(uri)
+      youtube_thumbnail(uri)
+    end
+
+    def self.niconico_video_id(uri)
+      case uri.host&.downcase
+      when 'www.nicovideo.jp', 'nicovideo.jp'
+        uri.path[%r{\A/watch/(sm\d+)\z}, 1]
+      when 'nico.ms'
+        uri.path[%r{\A/(sm\d+)\z}, 1]
+      end
     end
 
     def self.youtube_thumbnail(uri)
@@ -17,16 +26,6 @@ module Preview
       "https://i.ytimg.com/vi/#{ id }/hqdefault.jpg"
     end
 
-    def self.niconico_thumbnail(uri)
-      return unless ['www.nicovideo.jp', 'nicovideo.jp', 'nico.ms'].include?(uri.host&.downcase)
-
-      id = uri.path[%r{/(?:watch/)?(sm\d+)\z}, 1]
-      return unless id
-
-      numeric_id = id.delete_prefix('sm')
-      "https://nicovideo.cdn.nimg.jp/thumbnails/#{ numeric_id }/#{ numeric_id }.L"
-    end
-
-    private_class_method :youtube_thumbnail, :niconico_thumbnail
+    private_class_method :youtube_thumbnail
   end
 end