Deseasonify: separate seasonal definitions into new module

Since the original `seasons` package is now called just `exts`,
it makes sense to migrate all season-specific definitions out into
a separate module.

This module now contains everything relating to 'new' seasons, i.e.
just branding tooling.

1 files changed, 157 insertions, 0 deletions

diff --git a/bot/seasons.py b/bot/seasons.py
new file mode 100644
index 00000000..83a584fd
--- /dev/null
+++ b/bot/seasons.py
@@ -0,0 +1,157 @@
+import logging
+import typing as t
+from datetime import datetime
+
+from bot.constants import Colours, Month
+
+log = logging.getLogger(__name__)
+
+
+class SeasonBase:
+    """
+    Base for Seasonal classes.
+
+    This serves as the off-season fallback for when no specific
+    seasons are active.
+
+    Seasons are 'registered' simply by inheriting from `SeasonBase`.
+    We discover them by calling `__subclasses__`.
+    """
+
+    season_name: str = "Evergreen"
+    bot_name: str = "SeasonalBot"
+
+    colour: str = Colours.soft_green
+    description: str = "The default season!"
+
+    branding_path: str = "seasonal/evergreen"
+
+    months: t.Set[Month] = set(Month)
+
+
+class Christmas(SeasonBase):
+    """Branding for december."""
+
+    season_name = "Festive season"
+    bot_name = "Merrybot"
+
+    colour = Colours.soft_red
+    description = (
+        "The time is here to get into the festive spirit! No matter who you are, where you are, "
+        "or what beliefs you may follow, we hope every one of you enjoy this festive season!"
+    )
+
+    branding_path = "seasonal/christmas"
+
+    months = {Month.december}
+
+
+class Easter(SeasonBase):
+    """Branding for april."""
+
+    season_name = "Easter"
+    bot_name = "BunnyBot"
+
+    colour = Colours.bright_green
+    description = (
+        "Bunny here, bunny there, bunny everywhere! Here at Python Discord, we celebrate "
+        "our version of Easter during the entire month of April."
+    )
+
+    branding_path = "seasonal/easter"
+
+    months = {Month.april}
+
+
+class Halloween(SeasonBase):
+    """Branding for october."""
+
+    season_name = "Halloween"
+    bot_name = "NeonBot"
+
+    colour = Colours.orange
+    description = "Trick or treat?!"
+
+    branding_path = "seasonal/halloween"
+
+    months = {Month.october}
+
+
+class Pride(SeasonBase):
+    """Branding for june."""
+
+    season_name = "Pride"
+    bot_name = "ProudBot"
+
+    colour = Colours.pink
+    description = (
+        "The month of June is a special month for us at Python Discord. It is very important to us "
+        "that everyone feels welcome here, no matter their origin, identity or sexuality. During the "
+        "month of June, while some of you are participating in Pride festivals across the world, "
+        "we will be celebrating individuality and commemorating the history and challenges "
+        "of the LGBTQ+ community with a Pride event of our own!"
+    )
+
+    branding_path = "seasonal/pride"
+
+    months = {Month.june}
+
+
+class Valentines(SeasonBase):
+    """Branding for february."""
+
+    season_name = "Valentines"
+    bot_name = "TenderBot"
+
+    colour = Colours.pink
+    description = "Love is in the air!"
+
+    branding_path = "seasonal/valentines"
+
+    months = {Month.february}
+
+
+class Wildcard(SeasonBase):
+    """Branding for august."""
+
+    season_name = "Wildcard"
+    bot_name = "RetroBot"
+
+    colour = Colours.purple
+    description = "A season full of surprises!"
+
+    months = {Month.august}
+
+
+def get_current_season() -> t.Type[SeasonBase]:
+    """Give active season, based on current UTC month."""
+    current_month = Month(datetime.utcnow().month)
+
+    active_seasons = tuple(
+        season
+        for season in SeasonBase.__subclasses__()
+        if current_month in season.months
+    )
+
+    if not active_seasons:
+        return SeasonBase
+
+    if len(active_seasons) > 1:
+        log.warning(f"Multiple active season in month {current_month.name}")
+
+    return active_seasons[0]
+
+
+def get_season(name: str) -> t.Optional[t.Type[SeasonBase]]:
+    """
+    Give season such that its class name or its `season_name` attr match `name` (caseless).
+
+    If no such season exists, return None.
+    """
+    name = name.casefold()
+
+    for season in [SeasonBase] + SeasonBase.__subclasses__():
+        matches = (season.__name__.casefold(), season.season_name.casefold())
+
+        if name in matches:
+            return season