Add `wait_until_guild_available` coroutine

See docstring for explanation & comparison to the `on_ready` event.

This is taken from the Python bot repository. Originally implemented
by Mark. The `on_guild_available` callback was adapted and simplified
from the original implementation, as with Sentry in place, it is
believed that dispatching an error webhook is unnecessary.

Co-authored-by: MarkKoz <[email protected]>

1 files changed, 34 insertions, 0 deletions

diff --git a/bot/bot.py b/bot/bot.py
index 4f238df8..e460d9ab 100644
--- a/bot/bot.py
+++ b/bot/bot.py
@@ -44,6 +44,8 @@ class SeasonalBot(commands.Bot):
         self.http_session = ClientSession(
             connector=TCPConnector(resolver=AsyncResolver(), family=socket.AF_INET)
         )
+        self._guild_available = asyncio.Event()
+
         self.loop.create_task(self.send_log("SeasonalBot", "Connected!"))
 
     @property
@@ -168,5 +170,37 @@ class SeasonalBot(commands.Bot):
 
         await devlog.send(embed=embed)
 
+    async def on_guild_available(self, guild: discord.Guild) -> None:
+        """
+        Set the internal `_guild_available` event when PyDis guild becomes available.
+
+        If the cache appears to still be empty (no members, no channels, or no roles), the event
+        will not be set.
+        """
+        if guild.id != Client.guild:
+            return
+
+        if not guild.roles or not guild.members or not guild.channels:
+            log.warning("Guild available event was dispatched but the cache appears to still be empty!")
+            return
+
+        self._guild_available.set()
+
+    async def on_guild_unavailable(self, guild: discord.Guild) -> None:
+        """Clear the internal `_guild_available` event when PyDis guild becomes unavailable."""
+        if guild.id != Client.guild:
+            return
+
+        self._guild_available.clear()
+
+    async def wait_until_guild_available(self) -> None:
+        """
+        Wait until the PyDis guild becomes available (and the cache is ready).
+
+        The on_ready event is inadequate because it only waits 2 seconds for a GUILD_CREATE
+        gateway event before giving up and thus not populating the cache for unavailable guilds.
+        """
+        await self._guild_available.wait()
+
 
 bot = SeasonalBot(command_prefix=Client.prefix)