Support multiple locales from userLanguage cookie

lib/pleroma/web/gettext.ex

@@ -37,7 +37,7 @@ defmodule Pleroma.Web.Gettext do
 
   def normalize_locale(locale) do
     if is_binary(locale) do
-      String.replace(locale, "-", "_")
+      String.replace(locale, "-", "_", global: true)
     else
       nil
     end
@@ -51,13 +51,28 @@ defmodule Pleroma.Web.Gettext do
 
   def variant?(locale), do: String.contains?(locale, "_")
 
-  def supported_variants_of_locale(locale) do
-    cond do
-      variant?(locale) ->
-        [locale]
+  def language_for_variant(locale) do
+    Enum.at(String.split(locale, "_"), 0)
+  end
 
+  def ensure_fallbacks(locales) do
+    locales
+    |> Enum.flat_map(fn locale ->
+      others = other_supported_variants_of_locale(locale)
+        |> Enum.filter(fn l -> not Enum.member?(locales, l) end)
+
+      [locale] ++ others
+    end)
+  end
+
+  def other_supported_variants_of_locale(locale) do
+    cond do
       supports_locale?(locale) ->
-        [locale]
+        []
+
+      variant?(locale) ->
+        lang = language_for_variant(locale)
+        if supports_locale?(lang), do: [lang], else: []
 
       true ->
         Gettext.known_locales(Pleroma.Web.Gettext)

lib/pleroma/web/plugs/set_locale_plug.ex

@@ -26,11 +26,12 @@ defmodule Pleroma.Web.Plugs.SetLocalePlug do
     |> extract_preferred_language()
     |> normalize_language_codes()
     |> all_supported()
+    |> Enum.uniq()
   end
 
   defp all_supported(locales) do
     locales
-    |> Enum.flat_map(&Pleroma.Web.Gettext.supported_variants_of_locale/1)
+    |> Pleroma.Web.Gettext.ensure_fallbacks()
     |> Enum.filter(&supported_locale?/1)
   end
 
@@ -53,8 +54,7 @@ defmodule Pleroma.Web.Plugs.SetLocalePlug do
         []
 
       fe_lang ->
-        [fe_lang]
-        |> ensure_language_fallbacks()
+        String.split(fe_lang, ",")
     end
   end
 
@@ -67,7 +67,6 @@ defmodule Pleroma.Web.Plugs.SetLocalePlug do
         |> Enum.sort(&(&1.quality > &2.quality))
         |> Enum.map(& &1.tag)
         |> Enum.reject(&is_nil/1)
-        |> ensure_language_fallbacks()
 
       _ ->
         []
@@ -89,11 +88,4 @@ defmodule Pleroma.Web.Plugs.SetLocalePlug do
 
     %{tag: captures["tag"], quality: quality}
   end
-
-  defp ensure_language_fallbacks(tags) do
-    Enum.flat_map(tags, fn tag ->
-      [language | _] = String.split(tag, "-")
-      if Enum.member?(tags, language), do: [tag], else: [tag, language]
-    end)
-  end
 end