fix(ruyipkg): migrate to new locale fallback logic

Fixes: #173

ruyi/ruyipkg/msg.py

@@ -2,6 +2,9 @@
 
 from jinja2 import BaseLoader, Environment, TemplateNotFound
 
+from ..utils.l10n import match_lang_code
+
+
 RepoMessagesV1Type = TypedDict(
     "RepoMessagesV1Type",
     {
@@ -50,11 +53,8 @@ def from_object(cls, obj: object) -> "RepoMessageStore":
         return cls(obj)
 
     def get_message_template(self, msgid: str, lang_code: str) -> str | None:
-        if lang_code not in self._msgs_by_lang_code:
-            # TODO: fallback
-            return None
-
-        return self._msgs_by_lang_code[lang_code].get(msgid)
+        resolved_lang_code = match_lang_code(lang_code, self._msgs_by_lang_code.keys())
+        return self._msgs_by_lang_code[resolved_lang_code].get(msgid)
 
     def get_jinja(self, lang_code: str) -> Environment:
         if lang_code in self._cached_envs_by_lang_code:

ruyi/ruyipkg/news.py

@@ -6,6 +6,7 @@
 
 from ..config.news import NewsReadStatusStore
 from ..utils.porcelain import PorcelainEntity, PorcelainEntityType
+from ..utils.l10n import match_lang_code
 
 NEWS_FILENAME_RE = re.compile(r"^(\d+-\d{2}-\d{2}-.*?)(\.[0-9A-Za-z_-]+)?\.md$")
 
@@ -127,12 +128,8 @@ def __delitem__(self, lang: str) -> None:
         del self._content_by_lang[lang]
 
     def get_content_for_lang(self, lang: str) -> "NewsItemContent":
-        if lang in self:
-            return self[lang]
-
-        # fallback to the first (or indeed, only) language that's present
-        # this should be enough for our use
-        return list(self._content_by_lang.values())[0]
+        resolved_lang_code = match_lang_code(lang, self._content_by_lang.keys())
+        return self[resolved_lang_code]
 
     def to_porcelain(self) -> "PorcelainNewsItemV1":
         return {