propose language fallbacks

app/templating/I18hHelper.scala

@@ -1,15 +1,15 @@
 package lila.app
 package templating
 
+import scala.util.Random.shuffle
+
 import controllers._
-import lila.user.Context
 import lila.i18n.Env.{ current ⇒ i18nEnv }
 import lila.i18n.{ LangList, I18nDomain }
-
+import lila.user.Context
 import play.api.i18n.Lang
-import play.api.templates.Html
 import play.api.mvc.{ RequestHeader, Call }
-import scala.util.Random.shuffle
+import play.api.templates.Html
 
 trait I18nHelper {
 
@@ -38,7 +38,7 @@ trait I18nHelper {
 
   def langLinks(lang: Lang)(implicit ctx: Context) = Html {
     langLinksCache.getOrElseUpdate(lang.language, {
-      pool.names.toList sortBy (_._1) collect {
+      pool.names.toList sortBy (_._1) map {
         case (code, name) ⇒ """<li><a lang="%s" href="%s"%s>%s</a></li>""".format(
           code,
           langUrl(Lang(code))(I18nDomain(ctx.req.domain)),
@@ -48,11 +48,23 @@ trait I18nHelper {
     }).replace(uriPlaceholder, ctx.req.uri)
   }
 
+  def langFallbackLinks(implicit ctx: Context) = Html {
+    {
+      pool.preferredNames(ctx.req, 3) map {
+        case (code, name) ⇒ """<a class="lang_fallback" lang="%s" href="%s">%s</a>""".format(
+          code, langUrl(Lang(code))(I18nDomain(ctx.req.domain)), name)
+      } mkString ""
+    }.replace(uriPlaceholder, ctx.req.uri)
+  }
+
   def commonDomain(implicit ctx: Context): String =
     I18nDomain(ctx.req.domain).commonDomain
 
-  def acceptLanguages(implicit ctx: Context): String =
-    ctx.req.acceptLanguages.map(_.language).distinct mkString ","
+  def acceptLanguages(implicit ctx: Context): List[String] =
+    ctx.req.acceptLanguages.map(_.language.toString).toList.distinct
+
+  def acceptsLanguage(lang: Lang)(implicit ctx: Context): Boolean =
+    ctx.req.acceptLanguages exists (_.language == lang.language)
 
   private val uriPlaceholder = "[URI]"
 

app/views/base/layout.scala.html

@@ -32,7 +32,7 @@ themepicker: Boolean = false)(body: Html)(implicit ctx: Context)
 data-sound-file="@routes.Assets.at("sound/alert.ogg")"
 data-troll="@ctx.troll.toString"
 data-port="@netPort"
-data-accept-languages="@acceptLanguages">
+data-accept-languages="@acceptLanguages.mkString(",")">
 <div id="site_description">@trans.freeOnlineChessGamePlayChessNowInACleanInterfaceNoRegistrationNoAdsNoPluginRequiredPlayChessWithComputerFriendsOrRandomOpponents()</div>
 <div id="top" class="clearfix">
   <a title="@trans.toggleSound()" id="sound_state" class="available">
@@ -102,7 +102,11 @@ data-accept-languages="@acceptLanguages">
       <a id="site_title" href="@routes.Lobby.home">
         lichess<span class="extension">.org</span>
       </a>
+      @if(acceptsLanguage(lang)) {
       @baseline
+      } else {
+      @langFallbackLinks
+      }
     </h1>
     @menu.map { side =>
     <div class="side_menu">@side</div>

modules/i18n/src/main/I18nPool.scala

@@ -9,15 +9,19 @@ private[i18n] case class I18nPool(val langs: Set[Lang], val default: Lang) {
 
   def nonDefaultLangs = langs - default
 
-  val names: Map[String, String] = langs map { l ⇒
-    l.language -> LangList.nameOrCode(l.language)
-  } toMap
+  val names: Map[String, String] = (langs map langNames).toMap
+
+  private def langNames(lang: Lang): (String, String) =
+    lang.language -> LangList.nameOrCode(lang.language)
 
   def lang(req: RequestHeader) = domainLang(req) | default
 
   def preferred(req: RequestHeader) =
     (req.acceptLanguages find langs.contains) | default
 
+  def preferredNames(req: RequestHeader, nb: Int): Seq[(String, String)] =
+    req.acceptLanguages filter langs.contains take nb map langNames
+
   def domainLang(req: RequestHeader) =
     cache.getOrElseUpdate(req.domain, {
       I18nDomain(req.domain).lang filter langs.contains

public/javascripts/big.js

@@ -602,9 +602,10 @@ var storage = {
       });
     });
 
+    var acceptLanguages = $('body').data('accept-languages').split(',');
     $('#top .lichess_language').one('mouseover', function() {
       var $t = $(this);
-      _.each($('body').data('accept-languages').split(','), function(lang) {
+      _.each(acceptLanguages, function(lang) {
         $t.find('a[lang="' + lang + '"]').addClass('accepted');
       });
     });

public/stylesheets/common.css

@@ -362,6 +362,11 @@ body.tight #site_header {
 #site_header strong {
   font-weight: normal;
 }
+#site_header a.lang_fallback {
+  font-weight: bold;
+  display: inline-block;
+  margin-right: 1em;
+}
 body > div.content {
   width: 1005px;
   min-height: 590px;