[Core] Guild scoped I18n (#3896)

* Guild I18n

Never again!

* Finish off guild scoped i18n

* Black formatting

* Added guild only flags.

* Fix missing import.

* Added listing of guild i18n settings

* Added API support

* Added API support... properly!

* Added API support... for realsies!

* Auto-translate create_cases instances

You're welcome cog creators! Jack talked me into this!

* Fix get_regional_format to actually return properly

* Cleanup `set showsettings`

* Style pass

* Update redbot/core/core_commands.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Update redbot/core/events.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Update redbot/core/core_commands.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Fix missing import

* Improve caching

* Removal of unneeded function

* Fix some naming

* IDFK anymore...

* Reformat

* Update redbot/core/settings_caches.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Update redbot/core/settings_caches.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Update redbot/core/settings_caches.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Remove line number

* Fix global sets

* Set contextual locale manually where needed

* Reports cog is wonderful...

* Update redbot/core/core_commands.py

Co-authored-by: Draper <27962761+Drapersniper@users.noreply.github.com>

* Set contextual locale manually where needed in Mutes cog

* s

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>
Co-authored-by: Draper <27962761+Drapersniper@users.noreply.github.com>

redbot/cogs/alias/alias.py

@@ -170,7 +170,7 @@ class Alias(commands.Cog):
         for p in prefixes:
             if content.startswith(p):
                 return p
-        raise ValueError(_("No prefix found."))
+        raise ValueError("No prefix found.")
 
     async def call_alias(self, message: discord.Message, prefix: str, alias: AliasEntry):
         new_message = copy(message)

redbot/cogs/audio/core/events/lavalink.py

@@ -6,7 +6,7 @@ from pathlib import Path
 import discord
 import lavalink
 
-from redbot.core.i18n import Translator
+from redbot.core.i18n import Translator, set_contextual_locales_from_guild
 from ...errors import DatabaseError, TrackEnqueueError
 from ..abc import MixinMeta
 from ..cog_utils import CompositeMetaClass
@@ -31,6 +31,7 @@ class LavalinkEvents(MixinMeta, metaclass=CompositeMetaClass):
         guild_id = self.rgetattr(guild, "id", None)
         if not guild:
             return
+        await set_contextual_locales_from_guild(self.bot, guild)
         current_requester = self.rgetattr(current_track, "requester", None)
         current_stream = self.rgetattr(current_track, "is_stream", None)
         current_length = self.rgetattr(current_track, "length", None)

redbot/cogs/filter/filter.py

@@ -5,7 +5,7 @@ from typing import Union, Set, Literal
 
 from redbot.core import checks, Config, modlog, commands
 from redbot.core.bot import Red
-from redbot.core.i18n import Translator, cog_i18n
+from redbot.core.i18n import Translator, cog_i18n, set_contextual_locales_from_guild
 from redbot.core.utils import AsyncIter
 from redbot.core.utils.chat_formatting import pagify, humanize_list
 
@@ -396,6 +396,8 @@ class Filter(commands.Cog):
         if await self.bot.is_automod_immune(message):
             return
 
+        await set_contextual_locales_from_guild(self.bot, message.guild)
+
         await self.check_filter(message)
 
     @commands.Cog.listener()
@@ -429,6 +431,8 @@ class Filter(commands.Cog):
         if not guild_data["filter_names"]:
             return
 
+        await set_contextual_locales_from_guild(self.bot, guild)
+
         if await self.filter_hits(member.display_name, member.guild):
 
             name_to_use = guild_data["filter_default_name"]

redbot/cogs/mod/events.py

@@ -151,6 +151,9 @@ class Events(MixinMeta):
         # As are anyone configured to be
         if await self.bot.is_automod_immune(message):
             return
+
+        await i18n.set_contextual_locales_from_guild(self.bot, message.guild)
+
         deleted = await self.check_duplicates(message)
         if not deleted:
             await self.check_mention_spam(message)

redbot/cogs/mutes/mutes.py

@@ -194,6 +194,7 @@ class Mutes(VoiceMutes, commands.Cog, metaclass=CompositeMetaClass):
             guild = self.bot.get_guild(g_id)
             if guild is None or await self.bot.cog_disabled_in_guild(self, guild):
                 continue
+            await i18n.set_contextual_locales_from_guild(self.bot, guild)
             for u_id in self._server_mutes[guild.id]:
                 if self._server_mutes[guild.id][u_id]["until"] is None:
                     continue
@@ -295,6 +296,7 @@ class Mutes(VoiceMutes, commands.Cog, metaclass=CompositeMetaClass):
 
         for guild_id, users in multiple_mutes.items():
             guild = self.bot.get_guild(guild_id)
+            await i18n.set_contextual_locales_from_guild(self.bot, guild)
             for user, channels in users.items():
                 if len(channels) > 1:
                     task_name = f"server-unmute-channels-{guild_id}-{user}"
@@ -461,6 +463,7 @@ class Mutes(VoiceMutes, commands.Cog, metaclass=CompositeMetaClass):
         a = set(after.roles)
         roles_removed = list(b - a)
         roles_added = list(a - b)
+        await i18n.set_contextual_locales_from_guild(self.bot, guild)
         if mute_role in roles_removed:
             # send modlog case for unmute and remove from cache
             if guild.id not in self._server_mutes:
@@ -511,6 +514,7 @@ class Mutes(VoiceMutes, commands.Cog, metaclass=CompositeMetaClass):
         """
         if await self.bot.cog_disabled_in_guild(self, after.guild):
             return
+        await i18n.set_contextual_locales_from_guild(self.bot, after.guild)
         if after.id in self._channel_mutes:
             before_perms: Dict[int, Dict[str, Optional[bool]]] = {
                 o.id: {name: attr for name, attr in p} for o, p in before.overwrites.items()
@@ -569,6 +573,7 @@ class Mutes(VoiceMutes, commands.Cog, metaclass=CompositeMetaClass):
             # user to globally rate limit the bot therefore we are not
             # going to support re-muting users via channel overwrites
             return
+        await i18n.set_contextual_locales_from_guild(self.bot, guild)
         if guild.id in self._server_mutes:
             if member.id in self._server_mutes[guild.id]:
                 role = guild.get_role(mute_role)

redbot/cogs/reports/reports.py

@@ -11,7 +11,7 @@ from redbot.core.utils import AsyncIter
 from redbot.core.utils.chat_formatting import pagify, box
 from redbot.core.utils.antispam import AntiSpam
 from redbot.core.bot import Red
-from redbot.core.i18n import Translator, cog_i18n
+from redbot.core.i18n import Translator, cog_i18n, set_contextual_locales_from_guild
 from redbot.core.utils.predicates import MessagePredicate
 from redbot.core.utils.tunnel import Tunnel
 
@@ -346,8 +346,10 @@ class Reports(commands.Cog):
 
         if t is None:
             return
+        guild = t[0][0]
         tun = t[1]["tun"]
         if payload.user_id in [x.id for x in tun.members]:
+            await set_contextual_locales_from_guild(self.bot, guild)
             await tun.react_close(
                 uid=payload.user_id, message=_("{closer} has closed the correspondence")
             )
@@ -365,6 +367,7 @@ class Reports(commands.Cog):
                 to_remove.append(k)
                 continue
 
+            await set_contextual_locales_from_guild(self.bot, guild)
             topic = _("Re: ticket# {ticket_number} in {guild.name}").format(
                 ticket_number=ticket_number, guild=guild
             )
@@ -376,6 +379,7 @@ class Reports(commands.Cog):
         for key in to_remove:
             if tun := self.tunnel_store.pop(key, None):
                 guild, ticket = key
+                await set_contextual_locales_from_guild(self.bot, guild)
                 await tun["tun"].close_because_disabled(
                     _(
                         "Correspondence about ticket# {ticket_number} in "

redbot/cogs/streams/streams.py

@@ -1,7 +1,7 @@
 import discord
 from redbot.core.bot import Red
 from redbot.core import checks, commands, Config
-from redbot.core.i18n import cog_i18n, Translator
+from redbot.core.i18n import cog_i18n, Translator, set_contextual_locales_from_guild
 from redbot.core.utils._internal_utils import send_to_owners_with_prefix_replaced
 from redbot.core.utils.chat_formatting import escape, pagify
 
@@ -714,6 +714,9 @@ class Streams(commands.Cog):
                         ignore_reruns = await self.config.guild(channel.guild).ignore_reruns()
                         if ignore_reruns and is_rerun:
                             continue
+
+                        await set_contextual_locales_from_guild(self.bot, channel.guild)
+
                         mention_str, edited_roles = await self._get_mention_str(
                             channel.guild, channel
                         )

redbot/core/bot.py

@@ -41,14 +41,13 @@ from .data_manager import cog_data_path
 from .dev_commands import Dev
 from .events import init_events
 from .global_checks import init_global_checks
-
 from .settings_caches import (
     PrefixManager,
     IgnoreManager,
     WhitelistBlacklistManager,
     DisabledCogCache,
+    I18nManager,
 )
-
 from .rpc import RPCMixin
 from .utils import common_filters, AsyncIter
 from .utils._internal_utils import send_to_owners_with_prefix_replaced
@@ -142,6 +141,8 @@ class RedBase(
             disabled_commands=[],
             autoimmune_ids=[],
             delete_delay=-1,
+            locale=None,
+            regional_format=None,
         )
 
         self._config.register_channel(embeds=None, ignored=False)
@@ -159,6 +160,7 @@ class RedBase(
         self._disabled_cog_cache = DisabledCogCache(self._config)
         self._ignored_cache = IgnoreManager(self._config)
         self._whiteblacklist_cache = WhitelistBlacklistManager(self._config)
+        self._i18n_cache = I18nManager(self._config)
 
         async def prefix_manager(bot, message) -> List[str]:
             prefixes = await self._prefix_cache.get_prefixes(message.guild)

redbot/core/core_commands.py

@@ -1569,8 +1569,22 @@ class Core(commands.commands._RuleDropper, commands.Cog, CoreLogic):
             mod_role_ids = guild_data["mod_role"]
             mod_role_names = [r.name for r in guild.roles if r.id in mod_role_ids]
             mod_roles_str = humanize_list(mod_role_names) if mod_role_names else "Not Set."
-            guild_settings = _("Admin roles: {admin}\nMod roles: {mod}\n").format(
+
-                admin=admin_roles_str, mod=mod_roles_str
+            guild_locale = await i18n.get_locale_from_guild(self.bot, ctx.guild)
+            guild_regional_format = (
+                await i18n.get_regional_format_from_guild(self.bot, ctx.guild) or guild_locale
+            )
+
+            guild_settings = _(
+                "Admin roles: {admin}\n"
+                "Mod roles: {mod}\n"
+                "Locale: {guild_locale}\n"
+                "Regional format: {guild_regional_format}\n"
+            ).format(
+                admin=admin_roles_str,
+                mod=mod_roles_str,
+                guild_locale=guild_locale,
+                guild_regional_format=guild_regional_format,
             )
         else:
             guild_settings = ""
@@ -1578,7 +1592,7 @@ class Core(commands.commands._RuleDropper, commands.Cog, CoreLogic):
         prefixes = await ctx.bot._prefix_cache.get_prefixes(ctx.guild)
         global_data = await ctx.bot._config.all()
         locale = global_data["locale"]
-        regional_format = global_data["regional_format"] or _("Same as bot's locale")
+        regional_format = global_data["regional_format"] or locale
         colour = discord.Colour(global_data["color"])
 
         prefix_string = " ".join(prefixes)
@@ -1586,8 +1600,8 @@ class Core(commands.commands._RuleDropper, commands.Cog, CoreLogic):
             "{bot_name} Settings:\n\n"
             "Prefixes: {prefixes}\n"
             "{guild_settings}"
-            "Locale: {locale}\n"
+            "Global locale: {locale}\n"
-            "Regional format: {regional_format}\n"
+            "Global regional format: {regional_format}\n"
             "Default embed colour: {colour}"
         ).format(
             bot_name=ctx.bot.user.name,
@@ -2018,9 +2032,10 @@ class Core(commands.commands._RuleDropper, commands.Cog, CoreLogic):
 
     @_set.command()
     @checks.is_owner()
-    async def locale(self, ctx: commands.Context, language_code: str):
+    async def globallocale(self, ctx: commands.Context, language_code: str):
         """
-        Changes bot's locale.
+        Changes the bot's default locale.
+        This will be used when a server has not set a locale, or in DMs.
 
         `<language_code>` can be any language code with country code included,
         e.g. `en-US`, `de-DE`, `fr-FR`, `pl-PL`, etc.
@@ -2042,12 +2057,51 @@ class Core(commands.commands._RuleDropper, commands.Cog, CoreLogic):
             return
         standardized_locale_name = f"{locale.language}-{locale.territory}"
         i18n.set_locale(standardized_locale_name)
-        await ctx.bot._config.locale.set(standardized_locale_name)
+        await self.bot._i18n_cache.set_locale(None, standardized_locale_name)
+        await i18n.set_contextual_locales_from_guild(self.bot, ctx.guild)
+        await ctx.send(_("Global locale has been set."))
+
+    @_set.command()
+    @commands.guild_only()
+    @checks.guildowner_or_permissions(manage_guild=True)
+    async def locale(self, ctx: commands.Context, language_code: str):
+        """
+        Changes the bot's locale in this server.
+
+        `<language_code>` can be any language code with country code included,
+        e.g. `en-US`, `de-DE`, `fr-FR`, `pl-PL`, etc.
+
+        Go to Red's Crowdin page to see locales that are available with translations:
+        https://translate.discord.red
+
+        Use "default" to return to the bot's default set language.
+        To reset to English, use "en-US".
+        """
+        if language_code.lower() == "default":
+            global_locale = await self.bot._config.locale()
+            i18n.set_contextual_locale(global_locale)
+            await self.bot._i18n_cache.set_locale(ctx.guild, None)
+            await ctx.send(_("Locale has been set to the default."))
+            return
+        try:
+            locale = BabelLocale.parse(language_code, sep="-")
+        except (ValueError, UnknownLocaleError):
+            await ctx.send(_("Invalid language code. Use format: `en-US`"))
+            return
+        if locale.territory is None:
+            await ctx.send(
+                _("Invalid format - language code has to include country code, e.g. `en-US`")
+            )
+            return
+        standardized_locale_name = f"{locale.language}-{locale.territory}"
+        i18n.set_contextual_locale(standardized_locale_name)
+        await self.bot._i18n_cache.set_locale(ctx.guild, standardized_locale_name)
         await ctx.send(_("Locale has been set."))
 
-    @_set.command(aliases=["region"])
+    @_set.command(aliases=["globalregion"])
+    @commands.guild_only()
     @checks.is_owner()
-    async def regionalformat(self, ctx: commands.Context, language_code: str = None):
+    async def globalregionalformat(self, ctx: commands.Context, language_code: str = None):
         """
         Changes bot's regional format. This is used for formatting date, time and numbers.
 
@@ -2058,8 +2112,8 @@ class Core(commands.commands._RuleDropper, commands.Cog, CoreLogic):
         """
         if language_code is None:
             i18n.set_regional_format(None)
-            await ctx.bot._config.regional_format.set(None)
+            await self.bot._i18n_cache.set_regional_format(None, None)
-            await ctx.send(_("Regional formatting will now be based on bot's locale."))
+            await ctx.send(_("Global regional formatting will now be based on bot's locale."))
             return
 
         try:
@@ -2074,7 +2128,45 @@ class Core(commands.commands._RuleDropper, commands.Cog, CoreLogic):
             return
         standardized_locale_name = f"{locale.language}-{locale.territory}"
         i18n.set_regional_format(standardized_locale_name)
-        await ctx.bot._config.regional_format.set(standardized_locale_name)
+        await self.bot._i18n_cache.set_regional_format(None, standardized_locale_name)
+        await ctx.send(
+            _("Global regional formatting will now be based on `{language_code}` locale.").format(
+                language_code=standardized_locale_name
+            )
+        )
+
+    @_set.command(aliases=["region"])
+    @checks.guildowner_or_permissions(manage_guild=True)
+    async def regionalformat(self, ctx: commands.Context, language_code: str = None):
+        """
+        Changes bot's regional format in this server. This is used for formatting date, time and numbers.
+
+        `<language_code>` can be any language code with country code included,
+        e.g. `en-US`, `de-DE`, `fr-FR`, `pl-PL`, etc.
+
+        Leave `<language_code>` empty to base regional formatting on bot's locale in this server.
+        """
+        if language_code is None:
+            i18n.set_contextual_regional_format(None)
+            await self.bot._i18n_cache.set_regional_format(ctx.guild, None)
+            await ctx.send(
+                _("Regional formatting will now be based on bot's locale in this server.")
+            )
+            return
+
+        try:
+            locale = BabelLocale.parse(language_code, sep="-")
+        except (ValueError, UnknownLocaleError):
+            await ctx.send(_("Invalid language code. Use format: `en-US`"))
+            return
+        if locale.territory is None:
+            await ctx.send(
+                _("Invalid format - language code has to include country code, e.g. `en-US`")
+            )
+            return
+        standardized_locale_name = f"{locale.language}-{locale.territory}"
+        i18n.set_contextual_regional_format(standardized_locale_name)
+        await self.bot._i18n_cache.set_regional_format(ctx.guild, standardized_locale_name)
         await ctx.send(
             _("Regional formatting will now be based on `{language_code}` locale.").format(
                 language_code=standardized_locale_name

redbot/core/events.py

@@ -15,7 +15,12 @@ from pkg_resources import DistributionNotFound
 from redbot.core import data_manager
 
 from redbot.core.commands import RedHelpFormatter, HelpSettings
-from redbot.core.i18n import Translator
+from redbot.core.i18n import (
+    Translator,
+    set_contextual_locale,
+    set_contextual_regional_format,
+    set_contextual_locales_from_guild,
+)
 from .utils import AsyncIter
 from .. import __version__ as red_version, version_info as red_version_info, VersionInfo
 from . import commands
@@ -313,6 +318,8 @@ def init_events(bot, cli_flags):
 
     @bot.event
     async def on_message(message):
+        await set_contextual_locales_from_guild(bot, message.guild)
+
         await bot.process_commands(message)
         discord_now = message.created_at
         if (

redbot/core/i18n.py

@@ -1,13 +1,23 @@
+from __future__ import annotations
+
 import contextlib
 import functools
 import io
 import os
+import logging
+import discord
+
 from pathlib import Path
-from typing import Callable, Union, Dict, Optional
+from typing import Callable, TYPE_CHECKING, Union, Dict, Optional
+from contextvars import ContextVar
 
 import babel.localedata
 from babel.core import Locale
 
+if TYPE_CHECKING:
+    from redbot.core.bot import Red
+
+
 __all__ = [
     "get_locale",
     "set_locale",
@@ -16,10 +26,15 @@ __all__ = [
     "Translator",
     "get_babel_locale",
     "get_babel_regional_format",
+    "get_locale_from_guild",
+    "get_regional_format_from_guild",
+    "set_contextual_locales_from_guild",
 ]
 
-_current_locale = "en-US"
+log = logging.getLogger("red.i18n")
-_current_regional_format = None
+
+_current_locale = ContextVar("_current_locale", default="en-US")
+_current_regional_format = ContextVar("_current_regional_format", default=None)
 
 WAITING_FOR_MSGID = 1
 IN_MSGID = 2
@@ -33,24 +48,33 @@ _translators = []
 
 
 def get_locale() -> str:
-    return _current_locale
+    return str(_current_locale.get())
 
 
 def set_locale(locale: str) -> None:
     global _current_locale
-    _current_locale = locale
+    _current_locale = ContextVar("_current_locale", default=locale)
+    reload_locales()
+
+
+def set_contextual_locale(locale: str) -> None:
+    _current_locale.set(locale)
     reload_locales()
 
 
 def get_regional_format() -> str:
-    if _current_regional_format is None:
+    if _current_regional_format.get() is None:
-        return _current_locale
+        return str(_current_locale.get())
-    return _current_regional_format
+    return str(_current_regional_format.get())
 
 
 def set_regional_format(regional_format: Optional[str]) -> None:
     global _current_regional_format
-    _current_regional_format = regional_format
+    _current_regional_format = ContextVar("_current_regional_format", default=regional_format)
+
+
+def set_contextual_regional_format(regional_format: Optional[str]) -> None:
+    _current_regional_format.set(regional_format)
 
 
 def reload_locales() -> None:
@@ -58,6 +82,64 @@ def reload_locales() -> None:
         translator.load_translations()
 
 
+async def get_locale_from_guild(bot: Red, guild: Optional[discord.Guild]) -> str:
+    """
+    Get locale set for the given guild.
+
+    Parameters
+    ----------
+    bot: Red
+         The bot's instance.
+    guild: Optional[discord.Guild]
+         The guild contextual locale is set for.
+         Use `None` if the context doesn't involve guild.
+
+    Returns
+    -------
+    str
+        Guild's locale string.
+    """
+    return await bot._i18n_cache.get_locale(guild)
+
+
+async def get_regional_format_from_guild(bot: Red, guild: Optional[discord.Guild]) -> str:
+    """
+    Get regional format for the given guild.
+
+    Parameters
+    ----------
+    bot: Red
+         The bot's instance.
+    guild: Optional[discord.Guild]
+         The guild contextual locale is set for.
+         Use `None` if the context doesn't involve guild.
+
+    Returns
+    -------
+    str
+        Guild's locale string.
+    """
+    return await bot._i18n_cache.get_regional_format(guild)
+
+
+async def set_contextual_locales_from_guild(bot: Red, guild: Optional[discord.Guild]) -> None:
+    """
+    Set contextual locales (locale and regional format) for given guild context.
+
+    Parameters
+    ----------
+    bot: Red
+         The bot's instance.
+    guild: Optional[discord.Guild]
+         The guild contextual locale is set for.
+         Use `None` if the context doesn't involve guild.
+    """
+    locale = await get_locale_from_guild(bot, guild)
+    regional_format = await get_regional_format_from_guild(bot, guild)
+    set_contextual_locale(locale)
+    set_contextual_regional_format(regional_format)
+
+
 def _parse(translation_file: io.TextIOWrapper) -> Dict[str, str]:
     """
     Custom gettext parsing of translation files.
@@ -78,6 +160,10 @@ def _parse(translation_file: io.TextIOWrapper) -> Dict[str, str]:
     untranslated = ""
     translated = ""
     translations = {}
+    locale = get_locale()
+
+    translations[locale] = {}
+
     for line in translation_file:
         line = line.strip()
 
@@ -85,7 +171,7 @@ def _parse(translation_file: io.TextIOWrapper) -> Dict[str, str]:
             # New msgid
             if step is IN_MSGSTR and translated:
                 # Store the last translation
-                translations[_unescape(untranslated)] = _unescape(translated)
+                translations[locale][_unescape(untranslated)] = _unescape(translated)
             step = IN_MSGID
             untranslated = line[len(MSGID) : -1]
         elif line.startswith('"') and line.endswith('"'):
@@ -102,7 +188,7 @@ def _parse(translation_file: io.TextIOWrapper) -> Dict[str, str]:
 
     if step is IN_MSGSTR and translated:
         # Store the final translation
-        translations[_unescape(untranslated)] = _unescape(translated)
+        translations[locale][_unescape(untranslated)] = _unescape(translated)
     return translations
 
 
@@ -159,8 +245,9 @@ class Translator(Callable[[str], str]):
         This will look for the string in the translator's :code:`.pot` file,
         with respect to the current locale.
         """
+        locale = get_locale()
         try:
-            return self.translations[untranslated]
+            return self.translations[locale][untranslated]
         except KeyError:
             return untranslated
 
@@ -168,7 +255,16 @@ class Translator(Callable[[str], str]):
         """
         Loads the current translations.
         """
-        self.translations = {}
+        locale = get_locale()
+
+        if locale.lower() == "en-us":
+            # Red is written in en-US, no point in loading it
+            return
+        if locale in self.translations:
+            # Locales cannot be loaded twice as they have an entry in
+            # self.translations
+            return
+
         locale_path = get_locale_path(self.cog_folder, "po")
         with contextlib.suppress(IOError, FileNotFoundError):
             with locale_path.open(encoding="utf-8") as file:

redbot/core/modlog.py

@@ -15,7 +15,7 @@ from .utils.common_filters import (
     filter_urls,
     escape_spoilers,
 )
-from .i18n import Translator
+from .i18n import Translator, set_contextual_locales_from_guild
 
 from .generic_casetypes import all_generics
 
@@ -885,6 +885,7 @@ async def create_case(
         await _config.custom(_CASES, str(guild.id), str(next_case_number)).set(case.to_json())
         await _config.guild(guild).latest_case_number.set(next_case_number)
 
+    await set_contextual_locales_from_guild(bot, guild)
     bot.dispatch("modlog_case_create", case)
     try:
         mod_channel = await get_modlog_channel(case.guild)

redbot/core/settings_caches.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import Dict, List, Optional, Union, Set, Iterable, Tuple
+from typing import Dict, List, Optional, Union, Set, Iterable, Tuple, overload
 import asyncio
 from argparse import Namespace
 from collections import defaultdict
@@ -56,6 +56,93 @@ class PrefixManager:
             await self._config.guild_from_id(gid).prefix.set(prefixes)
 
 
+class I18nManager:
+    def __init__(self, config: Config):
+        self._config: Config = config
+        self._guild_locale: Dict[Union[int, None], Union[str, None]] = {}
+        self._guild_regional_format: Dict[Union[int, None], Union[str, None]] = {}
+
+    async def get_locale(self, guild: Union[discord.Guild, None]) -> str:
+        """Get the guild locale from the cache"""
+        # Ensure global locale is in the cache
+        if None not in self._guild_locale:
+            global_locale = await self._config.locale()
+            self._guild_locale[None] = global_locale
+
+        if guild is None:  # Not a guild so cannot support guild locale
+            # Return the bot's globally set locale if its None on a guild scope.
+            return self._guild_locale[None]
+        elif guild.id in self._guild_locale:  # Cached guild
+            if self._guild_locale[guild.id] is None:
+                return self._guild_locale[None]
+            else:
+                return self._guild_locale[guild.id]
+        else:  # Uncached guild
+            out = await self._config.guild(guild).locale()  # No locale set
+            if out is None:
+                self._guild_locale[guild.id] = None
+                return self._guild_locale[None]
+            else:
+                self._guild_locale[guild.id] = out
+                return out
+
+    @overload
+    async def set_locale(self, guild: None, locale: str):
+        ...
+
+    @overload
+    async def set_locale(self, guild: discord.Guild, locale: Union[str, None]):
+        ...
+
+    async def set_locale(
+        self, guild: Union[discord.Guild, None], locale: Union[str, None]
+    ) -> None:
+        """Set the locale in the config and cache"""
+        if guild is None:
+            if locale is None:
+                # this method should never be called like this
+                raise ValueError("Global locale can't be None!")
+            self._guild_locale[None] = locale
+            await self._config.locale.set(locale)
+            return
+        self._guild_locale[guild.id] = locale
+        await self._config.guild(guild).locale.set(locale)
+
+    async def get_regional_format(self, guild: Union[discord.Guild, None]) -> Optional[str]:
+        """Get the regional format from the cache"""
+        # Ensure global locale is in the cache
+        if None not in self._guild_regional_format:
+            global_regional_format = await self._config.regional_format()
+            self._guild_regional_format[None] = global_regional_format
+
+        if guild is None:  # Not a guild so cannot support guild locale
+            return self._guild_regional_format[None]
+        elif guild.id in self._guild_regional_format:  # Cached guild
+            if self._guild_regional_format[guild.id] is None:
+                return self._guild_regional_format[None]
+            else:
+                return self._guild_regional_format[guild.id]
+        else:  # Uncached guild
+            out = await self._config.guild(guild).regional_format()  # No locale set
+            if out is None:
+                self._guild_regional_format[guild.id] = None
+                return self._guild_regional_format[None]
+            else:  # Not cached, got a custom regional format.
+                self._guild_regional_format[guild.id] = out
+                return out
+
+    async def set_regional_format(
+        self, guild: Union[discord.Guild, None], regional_format: Union[str, None]
+    ) -> None:
+        """Set the regional format in the config and cache"""
+        if guild is None:
+            self._guild_regional_format[None] = regional_format
+            await self._config.regional_format.set(regional_format)
+            return
+        self._guild_regional_format[guild.id] = regional_format
+        await self._config.guild(guild).regional_format.set(regional_format)
+
+
 class IgnoreManager:
     def __init__(self, config: Config):
         self._config: Config = config