From b0dcbaa727e1faa8b6aa044ba9e4bfe055718387 Mon Sep 17 00:00:00 2001
From: Conatum <cona@thewisewolf.dev>
Date: Fri, 3 Mar 2023 15:35:08 +0200
Subject: [PATCH] rewrite (core): Split and refactor Lion and config.

---
 src/babel/cog.py                           |  12 +-
 src/core/cog.py                            |  19 +-
 src/core/guild_settings.py                 |   7 -
 src/core/lion.py                           | 211 ++++++++-------------
 src/core/user_settings.py                  |   7 -
 src/gui                                    |   2 +-
 src/meta/LionContext.py                    |   9 +-
 src/modules/economy/cog.py                 |   4 +-
 src/modules/shop/shops/base.py             |   8 +-
 src/modules/shop/shops/colours.py          |   2 +-
 src/modules/statistics/graphics/goals.py   |   4 +-
 src/modules/statistics/graphics/monthly.py |   4 +-
 src/modules/statistics/graphics/stats.py   |   2 +-
 src/modules/statistics/graphics/weekly.py  |   4 +-
 src/modules/statistics/ui/weeklymonthly.py |   6 +-
 src/modules/tasklist/cog.py                |   4 +-
 src/settings/groups.py                     |  64 +++++++
 src/utils/lib.py                           |  32 ++++
 18 files changed, 213 insertions(+), 188 deletions(-)
 delete mode 100644 src/core/guild_settings.py
 delete mode 100644 src/core/user_settings.py

diff --git a/src/babel/cog.py b/src/babel/cog.py
index b78e4650..0b598878 100644
--- a/src/babel/cog.py
+++ b/src/babel/cog.py
@@ -150,9 +150,9 @@ class BabelCog(LionCog):
     async def cog_load(self):
         if not self.bot.core:
             raise ValueError("CoreCog must be loaded first!")
-        self.bot.core.guild_settings.attach(LocaleSettings.ForceLocale)
-        self.bot.core.guild_settings.attach(LocaleSettings.GuildLocale)
-        self.bot.core.user_settings.attach(LocaleSettings.UserLocale)
+        self.bot.core.guild_config.register_model_setting(LocaleSettings.ForceLocale)
+        self.bot.core.guild_config.register_model_setting(LocaleSettings.GuildLocale)
+        self.bot.core.user_config.register_model_setting(LocaleSettings.UserLocale)
 
     async def cog_unload(self):
         pass
@@ -180,12 +180,12 @@ class BabelCog(LionCog):
         """
         locale = None
         if ctx.guild:
-            forced = ctx.alion.guild_settings['force_locale'].value
-            guild_locale = ctx.alion.guild_settings['guild_locale'].value
+            forced = ctx.lguild.config.get('force_locale').value
+            guild_locale = ctx.lguild.config.get('guild_locale').value
             if forced:
                 locale = guild_locale
 
-        locale = locale or ctx.alion.user_settings['user_locale'].value
+        locale = locale or ctx.luser.config.get('user_locale').value
         if ctx.interaction:
             locale = locale or ctx.interaction.locale.value
         if ctx.guild:
diff --git a/src/core/cog.py b/src/core/cog.py
index b286e55f..a307ad60 100644
--- a/src/core/cog.py
+++ b/src/core/cog.py
@@ -11,8 +11,9 @@ from settings.groups import SettingGroup
 
 from .data import CoreData
 from .lion import Lions
-from .guild_settings import GuildSettings
-from .user_settings import UserSettings
+from .lion_guild import GuildConfig
+from .lion_member import MemberConfig
+from .lion_user import UserConfig
 
 
 class CoreCog(LionCog):
@@ -20,7 +21,7 @@ class CoreCog(LionCog):
         self.bot = bot
         self.data = CoreData()
         bot.db.load_registry(self.data)
-        self.lions = Lions(bot)
+        self.lions = Lions(bot, self.data)
 
         self.app_config: Optional[CoreData.AppConfig] = None
         self.bot_config: Optional[CoreData.BotConfig] = None
@@ -35,19 +36,13 @@ class CoreCog(LionCog):
 
         # Some ModelSetting registries
         # These are for more convenient direct access
-        self.guild_settings = GuildSettings
-        self.user_settings = UserSettings
+        self.guild_config = GuildConfig
+        self.user_config = UserConfig
+        self.member_config = MemberConfig
 
         self.app_cmd_cache: list[discord.app_commands.AppCommand] = []
         self.cmd_name_cache: dict[str, discord.app_commands.AppCommand] = {}
 
-    async def bot_check_once(self, ctx: LionContext):  # type: ignore
-        lion = await self.lions.fetch(ctx.guild.id if ctx.guild else 0, ctx.author.id)
-        if ctx.guild:
-            await lion.touch_discord_models(ctx.author)  # type: ignore  # Type checker doesn't recognise guard
-        ctx.alion = lion
-        return True
-
     async def cog_load(self):
         # Fetch (and possibly create) core data rows.
         conn = await self.bot.db.get_connection()
diff --git a/src/core/guild_settings.py b/src/core/guild_settings.py
deleted file mode 100644
index 407235c0..00000000
--- a/src/core/guild_settings.py
+++ /dev/null
@@ -1,7 +0,0 @@
-from settings.groups import ModelSettings, SettingDotDict
-from .data import CoreData
-
-
-class GuildSettings(ModelSettings):
-    _settings = SettingDotDict()
-    model = CoreData.Guild
diff --git a/src/core/lion.py b/src/core/lion.py
index 9adae3a3..3f9ea1fe 100644
--- a/src/core/lion.py
+++ b/src/core/lion.py
@@ -1,153 +1,96 @@
 from typing import Optional
 from cachetools import LRUCache
+import datetime
 import discord
 
 from meta import LionCog, LionBot, LionContext
-from settings import InteractiveSetting
-from utils.lib import utc_now
 from data import WeakCache
 
 from .data import CoreData
 
-from .user_settings import UserSettings
-from .guild_settings import GuildSettings
-
-
-class Lion:
-    """
-    A Lion is a high level representation of a Member in the LionBot paradigm.
-
-    All members interacted with by the application should be available as Lions.
-    It primarily provides an interface to the User and Member data.
-    Lion also provides centralised access to various Member properties and methods,
-    that would normally be served by other cogs.
-
-    Many Lion methods may only be used when the required cogs and extensions are loaded.
-    A Lion may exist without a Bot instance or a Member in cache,
-    although the functionality available will be more limited.
-
-    There is no guarantee that a corresponding discord Member actually exists.
-    """
-    __slots__ = ('bot', 'data', 'user_data', 'guild_data', '_member', '__weakref__')
-
-    def __init__(self, bot: LionBot, data: CoreData.Member, user_data: CoreData.User, guild_data: CoreData.Guild):
-        self.bot = bot
-        self.data = data
-        self.user_data = user_data
-        self.guild_data = guild_data
-
-        self._member: Optional[discord.Member] = None
-
-    # Data properties
-
-    @property
-    def key(self):
-        return (self.data.guildid, self.data.userid)
-
-    @property
-    def guildid(self):
-        return self.data.guildid
-
-    @property
-    def userid(self):
-        return self.data.userid
-
-    @classmethod
-    def get(cls, guildid, userid):
-        return cls._cache_.get((guildid, userid), None)
-
-    # ModelSettings interfaces
-    @property
-    def guild_settings(self):
-        return GuildSettings(self.guildid, self.guild_data, bot=self.bot)
-
-    @property
-    def user_settings(self):
-        return UserSettings(self.userid, self.user_data, bot=self.bot)
-
-    # Setting interfaces
-    # Each of these return an initialised member setting
-
-    @property
-    def timezone(self):
-        pass
-
-    @property
-    def locale(self):
-        pass
-
-    # Time utilities
-    @property
-    def now(self):
-        """
-        Returns current time-zone aware time for the member.
-        """
-        pass
-
-    # Discord data cache
-    async def touch_discord_models(self, member: discord.Member):
-        """
-        Update the stored discord data from the given user or member object.
-        Intended to be used when we get member data from events that may not be available in cache.
-        """
-        # Can we do these in one query?
-        if member.guild and (self.guild_data.name != member.guild.name):
-            await self.guild_data.update(name=member.guild.name)
-
-        avatar_key = member.avatar.key if member.avatar else None
-        await self.user_data.update(avatar_hash=avatar_key, name=member.name, last_seen=utc_now())
-
-        if member.display_name != self.data.display_name:
-            await self.data.update(display_name=member.display_name)
-
-    async def get_member(self) -> Optional[discord.Member]:
-        """
-        Retrieve the member object for this Lion, if possible.
-
-        If the guild or member cannot be retrieved, returns None.
-        """
-        guild = self.bot.get_guild(self.guildid)
-        if guild is not None:
-            member = guild.get_member(self.userid)
-            if member is None:
-                try:
-                    member = await guild.fetch_member(self.userid)
-                except discord.HTTPException:
-                    pass
-            return member
+from .lion_guild import LionGuild
+from .lion_user import LionUser
+from .lion_member import LionMember
 
 
 class Lions(LionCog):
-    def __init__(self, bot: LionBot):
+    def __init__(self, bot: LionBot, data: CoreData):
         self.bot = bot
+        self.data = data
 
-        # Full Lions cache
-        # Don't expire Lions with strong references
-        self._cache_: WeakCache[tuple[int, int], 'Lion'] = WeakCache(LRUCache(5000))
+        # Caches
+        # Using WeakCache so strong references stay consistent
+        self.lion_guilds = WeakCache(LRUCache(2500))
+        self.lion_users = WeakCache(LRUCache(2000))
+        self.lion_members = WeakCache(LRUCache(5000))
 
-        self._settings_: dict[str, InteractiveSetting] = {}
-
-    async def fetch(self, guildid, userid) -> Lion:
+    async def bot_check_once(self, ctx: LionContext):
         """
-        Fetch or create the given Member.
-        If the guild or user row doesn't exist, also creates it.
-        Relies on the core cog existing, to retrieve the core data.
+        Insert the high-level Lion objects into context before command execution.
+
+        Creates the objects if they do not already exist.
+        Updates relevant saved data from the Discord models,
+        and updates last seen for the LionUser (for data lifetime).
         """
-        # TODO: Find a way to reduce this to one query, while preserving cache
-        lion = self._cache_.get((guildid, userid))
-        if lion is None:
-            if self.bot.core:
-                data = self.bot.core.data
-            else:
-                raise ValueError("Cannot fetch Lion before core module is attached.")
+        if ctx.guild:
+            # TODO: Consider doing all updates in one query, maybe with a View trigger on Member
+            lmember = ctx.lmember = await self.fetch_member(ctx.guild.id, ctx.author.id, ctx.author)
+            await lmember.touch_discord_model(ctx.author)
 
-            guild = await data.Guild.fetch_or_create(guildid)
-            user = await data.User.fetch_or_create(userid)
-            member = await data.Member.fetch_or_create(guildid, userid)
-            lion = Lion(self.bot, member, user, guild)
-            self._cache_[(guildid, userid)] = lion
-        return lion
+            ctx.luser = lmember.luser
+            await ctx.luser.touch_discord_model(ctx.author, seen=True)
 
-    def add_model_setting(self, setting: InteractiveSetting):
-        self._settings_[setting.__class__.__name__] = setting
-        return setting
+            ctx.lguild = lmember.lguild
+            await ctx.lguild.touch_discord_model(ctx.guild)
+
+            ctx.alion = lmember
+        else:
+            ctx.lmember = ctx.alion = None
+            ctx.lguild = None
+            luser = ctx.luser = await self.fetch_user(ctx.author.id, ctx.author)
+
+            await luser.touch_discord_model(ctx.author)
+
+            ctx.alion = luser
+        return True
+
+    async def fetch_user(self, userid, user: Optional[discord.User] = None) -> LionUser:
+        """
+        Fetch the given LionUser, hitting cache if possible.
+
+        Creates the LionUser if it does not exist.
+        """
+        if (luser := self.lion_users.get(userid, None)) is None:
+            data = await self.data.User.fetch_or_create(userid)
+            luser = LionUser(self.bot, data, user=user)
+            self.lion_users[userid] = luser
+        return luser
+
+    async def fetch_guild(self, guildid, guild: Optional[discord.Guild] = None) -> LionGuild:
+        """
+        Fetch the given LionGuild, hitting cache if possible.
+
+        Creates the LionGuild if it does not exist.
+        """
+        if (lguild := self.lion_guilds.get(guildid, None)) is None:
+            data = await self.data.Guild.fetch_or_create(guildid)
+            lguild = LionGuild(self.bot, data, guild=guild)
+            self.lion_guilds[guildid] = lguild
+        return lguild
+
+    async def fetch_member(self, guildid, userid, member: Optional[discord.Member] = None) -> LionMember:
+        """
+        Fetch the given LionMember, using cache for data if possible.
+
+
+        Creates the LionGuild, LionUser, and LionMember if they do not already exist.
+        """
+        # TODO: Can we do this more efficiently with one query, while keeping cache? Multiple joins?
+        key = (guildid, userid)
+        if (lmember := self.lion_members.get(key, None)) is None:
+            lguild = await self.fetch_guild(guildid, member.guild if member is not None else None)
+            luser = await self.fetch_user(userid, member)
+            data = await self.data.Member.fetch_or_create(guildid, userid)
+            lmember = LionMember(self.bot, data, lguild, luser, member)
+            self.lion_members[key] = lmember
+        return lmember
diff --git a/src/core/user_settings.py b/src/core/user_settings.py
deleted file mode 100644
index 8dc69b0a..00000000
--- a/src/core/user_settings.py
+++ /dev/null
@@ -1,7 +0,0 @@
-from settings.groups import ModelSettings, SettingDotDict
-from .data import CoreData
-
-
-class UserSettings(ModelSettings):
-    _settings = SettingDotDict()
-    model = CoreData.User
diff --git a/src/gui b/src/gui
index 4f3d5740..2beff63d 160000
--- a/src/gui
+++ b/src/gui
@@ -1 +1 @@
-Subproject commit 4f3d5740a3bdddec37a7f7f2e3b55e8a8e23b674
+Subproject commit 2beff63ddc42685f7ec153c6eb5adf536428da4c
diff --git a/src/meta/LionContext.py b/src/meta/LionContext.py
index ebef4de0..4f781381 100644
--- a/src/meta/LionContext.py
+++ b/src/meta/LionContext.py
@@ -8,7 +8,9 @@ from discord.ext.commands import Context
 
 if TYPE_CHECKING:
     from .LionBot import LionBot
-    from core.lion import Lion
+    from core.lion_member import LionMember
+    from core.lion_user import LionUser
+    from core.lion_guild import LionGuild
 
 
 logger = logging.getLogger(__name__)
@@ -45,7 +47,10 @@ class LionContext(Context['LionBot']):
     Extends Context to add Lion-specific methods and attributes.
     Also adds several contextual wrapped utilities for simpler user during command invocation.
     """
-    alion: 'Lion'
+    luser: 'LionUser'
+    lguild: 'LionGuild'
+    lmember: 'LionMember'
+    alion: 'LionUser | LionMember'
 
     def __repr__(self):
         parts = {}
diff --git a/src/modules/economy/cog.py b/src/modules/economy/cog.py
index 560b9e39..4daab0fa 100644
--- a/src/modules/economy/cog.py
+++ b/src/modules/economy/cog.py
@@ -415,7 +415,7 @@ class Economy(LionCog):
                         ).on_conflict(ignore=True)
             else:
                 # With only one target, we can take a simpler path, and make better use of local caches.
-                await self.bot.core.lions.fetch(ctx.guild.id, target.id)
+                await self.bot.core.lions.fetch_member(ctx.guild.id, target.id)
             # Now we are certain these members have a database row
 
             # Perform the appropriate action
@@ -889,7 +889,7 @@ class Economy(LionCog):
 
         t = self.bot.translator.t
         Member = self.bot.core.data.Member
-        target_lion = await self.bot.core.lions.fetch(ctx.guild.id, target.id)
+        target_lion = await self.bot.core.lions.fetch_member(ctx.guild.id, target.id)
 
         # TODO: Add a "Send thanks" button to the DM?
         # Alternative flow could be waiting until the target user presses accept
diff --git a/src/modules/shop/shops/base.py b/src/modules/shop/shops/base.py
index f66aa43c..34faa398 100644
--- a/src/modules/shop/shops/base.py
+++ b/src/modules/shop/shops/base.py
@@ -11,7 +11,7 @@ from babel.translator import LazyStr
 from ..data import ShopData
 
 if TYPE_CHECKING:
-    from core.lion import Lion
+    from core.lion_member import LionMember
 
 
 class ShopCog(LionCog):
@@ -65,7 +65,7 @@ class Customer:
         self.bot = bot
         self.data = shop_data
 
-        self.lion: 'Lion' = lion
+        self.lion: 'LionMember' = lion
 
         # A list of InventoryItems held by this customer
         self.inventory = inventory
@@ -84,7 +84,7 @@ class Customer:
 
     @classmethod
     async def fetch(cls, bot: LionBot, shop_data: ShopData, guildid: int, userid: int):
-        lion = await bot.core.lions.fetch(guildid, userid)
+        lion = await bot.core.lions.fetch_member(guildid, userid)
         inventory = await shop_data.MemberInventoryInfo.fetch_inventory_info(guildid, userid)
         return cls(bot, shop_data, lion, inventory)
 
@@ -92,7 +92,7 @@ class Customer:
         """
         Refresh the data for this member.
         """
-        self.lion = await self.bot.core.lions.fetch(self.guildid, self.userid)
+        self.lion = await self.bot.core.lions.fetch_member(self.guildid, self.userid)
         await self.lion.data.refresh()
         self.inventory = await self.data.MemberInventoryInfo.fetch_inventory_info(self.guildid, self.userid)
         return self
diff --git a/src/modules/shop/shops/colours.py b/src/modules/shop/shops/colours.py
index 58b7cbe1..93e301b1 100644
--- a/src/modules/shop/shops/colours.py
+++ b/src/modules/shop/shops/colours.py
@@ -184,7 +184,7 @@ class ColourShop(Shop):
                 )
 
             # Ensure the customer member actually exists
-            member = await self.customer.lion.get_member()
+            member = await self.customer.lion.fetch_member()
             if member is None:
                 raise SafeCancellation(
                     t(_p(
diff --git a/src/modules/statistics/graphics/goals.py b/src/modules/statistics/graphics/goals.py
index 3a64318a..48a9c7f7 100644
--- a/src/modules/statistics/graphics/goals.py
+++ b/src/modules/statistics/graphics/goals.py
@@ -15,7 +15,7 @@ async def get_goals_card(
 ):
     data: StatsData = bot.get_cog('StatsCog').data
 
-    lion = await bot.core.lions.fetch(guildid, userid)
+    lion = await bot.core.lions.fetch_member(guildid, userid)
     today = lion.today
 
     # Calculate periodid and select the correct model
@@ -63,7 +63,7 @@ async def get_goals_card(
     sessions_complete = 0.5
 
     # Get member profile
-    if member := await lion.get_member():
+    if member := await lion.fetch_member():
         username = (member.display_name, member.discriminator)
         avatar = member.avatar.key
     else:
diff --git a/src/modules/statistics/graphics/monthly.py b/src/modules/statistics/graphics/monthly.py
index 550edf11..f59e29f6 100644
--- a/src/modules/statistics/graphics/monthly.py
+++ b/src/modules/statistics/graphics/monthly.py
@@ -14,7 +14,7 @@ from ..lib import apply_month_offset
 async def get_monthly_card(bot: LionBot, userid: int, guildid: int, offset: int, mode: CardMode) -> MonthlyStatsCard:
     data: StatsData = bot.get_cog('StatsCog').data
 
-    lion = await bot.core.lions.fetch(guildid, userid)
+    lion = await bot.core.lions.fetch_member(guildid, userid)
     today = lion.today
     month_start = today.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
     target = apply_month_offset(month_start, offset)
@@ -77,7 +77,7 @@ async def get_monthly_card(bot: LionBot, userid: int, guildid: int, offset: int,
             monthly[i][day.day - 1] = stat / 3600
 
     # Get member profile
-    if member := await lion.get_member():
+    if member := await lion.fetch_member():
         username = (member.display_name, member.discriminator)
     else:
         username = (lion.data.display_name, '#????')
diff --git a/src/modules/statistics/graphics/stats.py b/src/modules/statistics/graphics/stats.py
index 9aa62fff..2ce3d355 100644
--- a/src/modules/statistics/graphics/stats.py
+++ b/src/modules/statistics/graphics/stats.py
@@ -16,7 +16,7 @@ async def get_stats_card(bot: LionBot, userid: int, guildid: int):
     # TODO: Leaderboard rankings
     guildid = guildid or 0
 
-    lion = await bot.core.lions.fetch(guildid, userid)
+    lion = await bot.core.lions.fetch_member(guildid, userid)
 
     # Calculate the period timestamps, i.e. start time for each summary period
     # TODO: Don't do the alltime one like this, not efficient anymore
diff --git a/src/modules/statistics/graphics/weekly.py b/src/modules/statistics/graphics/weekly.py
index 953b3c39..75d02e2b 100644
--- a/src/modules/statistics/graphics/weekly.py
+++ b/src/modules/statistics/graphics/weekly.py
@@ -12,7 +12,7 @@ from ..data import StatsData
 async def get_weekly_card(bot: LionBot, userid: int, guildid: int, offset: int, mode: CardMode) -> WeeklyStatsCard:
     data: StatsData = bot.get_cog('StatsCog').data
 
-    lion = await bot.core.lions.fetch(guildid, userid)
+    lion = await bot.core.lions.fetch_member(guildid, userid)
     today = lion.today
     week_start = today - timedelta(days=today.weekday()) - timedelta(weeks=offset)
     days = [week_start + timedelta(i) for i in range(-7, 7 if offset else (today.weekday() + 1))]
@@ -34,7 +34,7 @@ async def get_weekly_card(bot: LionBot, userid: int, guildid: int, offset: int,
         day_stats.append(0)
 
     # Get member profile
-    if member := await lion.get_member():
+    if member := await lion.fetch_member():
         username = (member.display_name, member.discriminator)
     else:
         username = (lion.data.display_name, '#????')
diff --git a/src/modules/statistics/ui/weeklymonthly.py b/src/modules/statistics/ui/weeklymonthly.py
index 1222e1cb..7520e925 100644
--- a/src/modules/statistics/ui/weeklymonthly.py
+++ b/src/modules/statistics/ui/weeklymonthly.py
@@ -21,7 +21,7 @@ from babel.translator import ctx_translator, LazyStr
 from babel.utils import local_month
 from gui.cards import WeeklyGoalCard, WeeklyStatsCard, MonthlyGoalCard, MonthlyStatsCard
 from gui.base import CardMode
-from core.lion import Lion
+from core.lion_member import LionMember
 
 from ..graphics.weekly import get_weekly_card
 from ..graphics.monthly import get_monthly_card
@@ -338,7 +338,7 @@ class WeeklyMonthlyUI(StatsUI):
         self.data: StatsData = bot.get_cog('StatsCog').data
 
         # State
-        self.lion: Optional[Lion] = None
+        self.lion: Optional[LionMember] = None
 
         self._stat_page: StatPage = StatPage.WEEKLY_VOICE
         self._week_offset = 0
@@ -859,7 +859,7 @@ class WeeklyMonthlyUI(StatsUI):
         """
         self._original = interaction
         self._showing_global = False
-        self.lion = await self.bot.core.lions.fetch(self.guildid, self.userid)
+        self.lion = await self.bot.core.lions.fetch_member(self.guildid, self.userid)
 
         # TODO: Switch to using data cache in reload to calculate global/local
 
diff --git a/src/modules/tasklist/cog.py b/src/modules/tasklist/cog.py
index 407feeeb..5011b517 100644
--- a/src/modules/tasklist/cog.py
+++ b/src/modules/tasklist/cog.py
@@ -130,8 +130,8 @@ class TasklistCog(LionCog):
 
     async def cog_load(self):
         await self.data.init()
-        self.bot.core.guild_settings.attach(self.settings.task_reward)
-        self.bot.core.guild_settings.attach(self.settings.task_reward_limit)
+        self.bot.core.guild_config.register_model_setting(self.settings.task_reward)
+        self.bot.core.guild_config.register_model_setting(self.settings.task_reward_limit)
 
         # TODO: Better method for getting single load
         # Or better, unloading crossloaded group
diff --git a/src/settings/groups.py b/src/settings/groups.py
index 66764c7c..96e768c3 100644
--- a/src/settings/groups.py
+++ b/src/settings/groups.py
@@ -88,6 +88,70 @@ class ModelSetting(ModelData, BaseSetting):
     ...
 
 
+class ModelConfig:
+    """
+    A ModelConfig provides a central point of configuration for any object described by a single Model.
+
+    An instance of a ModelConfig represents configuration for a single object
+    (given by a single row of the corresponding Model).
+
+    The ModelConfig also supports registration of non-model configuration,
+    to support associated settings (e.g. list-settings) for the object.
+
+    This is an ABC, and must be subclassed for each object-type.
+    """
+    settings: SettingDotDict
+    _model_settings: set
+    model: Type[RowModel]
+
+    def __init__(self, parent_id, row, **kwargs):
+        self.parent_id = parent_id
+        self.row = row
+        self.kwargs = kwargs
+
+    @classmethod
+    def register_setting(cls, setting_cls):
+        """
+        Decorator to register a non-model setting as part of the object configuration.
+
+        The setting class may be re-accessed through the `settings` class attr.
+
+        Subclasses may provide alternative access pathways to key non-model settings.
+        """
+        cls.settings[setting_cls.setting_id] = setting_cls
+        return setting_cls
+
+    @classmethod
+    def register_model_setting(cls, model_setting_cls):
+        """
+        Decorator to register a model setting as part of the object configuration.
+
+        The setting class may be accessed through the `settings` class attr.
+
+        A fresh setting instance may also be retrieved (using cached data)
+        through the `get` instance method.
+
+        Subclasses are recommended to provide model settings as properties
+        for simplified access and type checking.
+        """
+        cls._model_settings.add(model_setting_cls.setting_id)
+        return cls.register_setting(model_setting_cls)
+
+    def get(self, setting_id):
+        """
+        Retrieve a freshly initialised copy of the given model-setting.
+
+        The given `setting_id` must have been previously registered through `register_model_setting`.
+        This uses cached data, and so is not guaranteed to be up-to-date.
+        """
+        if setting_id not in self._model_settings:
+            # TODO: Log
+            raise ValueError
+        setting_cls = self.settings[setting_id]
+        data = setting_cls._read_from_row(self.parent_id, self.row, **self.kwargs)
+        return setting_cls(self.parent_id, data, **self.kwargs)
+
+
 class ModelSettings:
     """
     A ModelSettings instance aggregates multiple `ModelSetting` instances
diff --git a/src/utils/lib.py b/src/utils/lib.py
index 59802221..aa0afc4c 100644
--- a/src/utils/lib.py
+++ b/src/utils/lib.py
@@ -1,6 +1,7 @@
 from typing import NamedTuple, Optional, Sequence, Union, overload, List
 import datetime
 import iso8601  # type: ignore
+import pytz
 import re
 from contextvars import Context
 
@@ -706,3 +707,34 @@ def parse_duration(string: str) -> Optional[int]:
             seconds += int(match.group('value')) * multiplier
 
     return seconds if found else None
+
+
+class Timezoned:
+    """
+    ABC mixin for objects with a set timezone.
+
+    Provides several useful localised properties.
+    """
+    __slots__ = ()
+
+    @property
+    def timezone(self) -> pytz.timezone:
+        """
+        Must be implemented by the deriving class!
+        """
+        raise NotImplementedError
+
+    @property
+    def now(self):
+        """
+        Return the current time localised to the object's timezone.
+        """
+        return datetime.datetime.now(tz=self.timezone)
+
+    @property
+    def today(self):
+        """
+        Return the start of the day localised to the object's timezone.
+        """
+        now = self.now
+        return now.replace(hour=0, minute=0, second=0, microsecond=0)