main: set up basic bot without commands

As the summary says, this sets up a basic bot that doesn't listen to
any commands yet; the bot just runs and does nothing.

Signed-off-by: Max R. Carrara <max@aequito.sh>

src/bot/main.py

@@ -1,6 +1,189 @@
-def main():
-    print("Hello world!")
+import asyncio
+import logging
+import logging.handlers
+import os
+import sys
 
 
-if __name__ == "__main__":
-    main()
+import discord
+from discord.ext import commands
+
+from bot.env import Environment
+
+
+_log: logging.Logger
+
+
+def setup_logging() -> logging.Logger:
+    root_logger = logging.getLogger(__name__)
+
+    log_level_map = {
+        "NOTSET": logging.NOTSET,
+        "DEBUG": logging.DEBUG,
+        "INFO": logging.INFO,
+        "WARNING": logging.WARNING,
+        "ERROR": logging.ERROR,
+        "CRITICAL": logging.CRITICAL,
+    }
+
+    env_log_level = Environment.bot_log_level()
+    log_level: int = log_level_map.get(env_log_level, logging.INFO)
+
+    root_logger.setLevel(log_level)
+
+    dt_fmt = "%Y-%m-%d %H:%M:%S"
+
+    log_formatter = logging.Formatter(
+        "[{asctime}] [{levelname}] {name}: {message}", dt_fmt, style="{"
+    )
+
+    # Log everything to rotating files
+    log_file_handler = logging.handlers.RotatingFileHandler(
+        filename="bot.log", encoding="utf-8", maxBytes=32 * 1024 * 1024, backupCount=5
+    )
+    log_file_handler.setFormatter(log_formatter)
+    root_logger.addHandler(log_file_handler)
+
+    # Log everything to stderr also
+    log_stream_handler = logging.StreamHandler()
+    log_stream_handler.setFormatter(log_formatter)
+    root_logger.addHandler(log_stream_handler)
+
+    # Also log errors to a separate file for easier debugging
+    log_error_file_handler = logging.FileHandler(
+        filename="bot_err.log", encoding="utf-8"
+    )
+    log_error_file_handler.setFormatter(log_formatter)
+    log_error_file_handler.setLevel(logging.ERROR)
+    root_logger.addHandler(log_error_file_handler)
+
+    return root_logger
+
+
+def setup_bot() -> commands.Bot:
+    intents = discord.Intents.all()
+
+    desc_paragraphs = [
+        """Der VW Phaeton ist eine viertürige Stufenheck-Limousine der Oberklasse
+        der Marke Volkswagen. Die Herstellung war ein Gemeinschaftsprojekt des
+        Volkswagenwerks Zwickau mit der Gläsernen Manufaktur Dresden, wo die
+        Endmontage großteils in Handarbeit erfolgte. Vom Produktionsstart am
+        11. Dezember 2001 bis zum Produktionsende am 18. März 2016 wurden
+        84.235 Fahrzeuge gebaut.""",
+        """In der Nacht zum 11. Oktober 2008 kam Haider in Lambichl im Südwesten
+        der Landeshauptstadt Klagenfurt ♁(Lage) auf der Loiblpass-Straße bei
+        einem Verkehrsunfall ums Leben. Nach dem Besuch mehrerer
+        Veranstaltungen und Gaststätten hatte sich Haider, stark alkoholisiert
+        (1,8 ‰ Blutalkoholkonzentration), allein auf den Weg zu seinem Haus im
+        Bärental gemacht. Nach Angaben des Leiters der Staatsanwaltschaft
+        Klagenfurt fuhr Haider bei Nebel mit stark überhöhter Geschwindigkeit
+        mit seinem Dienstwagen VW Phaeton V6.""",
+    ]
+
+    description = "\n\n".join(
+        " ".join(line.strip() for line in paragraph) for paragraph in desc_paragraphs
+    )
+
+    command_prefix = Environment.bot_prefix()
+
+    return commands.Bot(
+        command_prefix=command_prefix, description=description, intents=intents
+    )
+
+
+def read_token_file() -> str:
+    bot_token_path = Environment.bot_token_path()
+
+    if not bot_token_path.exists():
+        raise FileNotFoundError(
+            f'Cannot read bot token - path "{bot_token_path}" does not exist'
+        )
+
+    try:
+        token = bot_token_path.read_text("utf-8").strip()
+        return token
+
+    except Exception as e:
+        _log.error(
+            'Failed to read token from path "{bot_token_path}"', exc_info=sys.exc_info()
+        )
+        raise e
+
+
+bot = setup_bot()
+
+
+@bot.event
+async def on_error(event: str, *args, **kwargs):
+    _log.error(
+        f"Encountered unexpected exception while processing event {event} ({args = }; {kwargs = }):",
+        exc_info=sys.exc_info(),
+    )
+
+
+@bot.event
+async def on_ready():
+    _log.info("Ready: Connected to Discord")
+
+
+@bot.event
+async def on_resumed():
+    _log.info("Resumed: Session with Discord resumed")
+
+
+@bot.event
+async def on_shard_ready(shard_id: int):
+    _log.info(f"Ready: Shard ID {shard_id} connected to Discord")
+
+
+@bot.event
+async def on_shard_resumed(shard_id: int):
+    _log.info(f"Resumed: Shard ID {shard_id} resumed session with Discord")
+
+
+@bot.event
+async def on_message(message: discord.Message):
+    _log.debug(f"Read message ({message.id = }): {message.content}")
+
+
+@bot.event
+async def on_command(ctx: commands.Context):
+    _log.debug(
+        f"Command invoked:"
+        f" {ctx.command = }; {ctx.message.author = }; {ctx.message.id = }"
+    )
+
+
+@bot.event
+async def on_command_completion(ctx: commands.Context):
+    _log.debug(
+        f"Command completed:"
+        f" {ctx.command = }; {ctx.message.author = }; {ctx.message.id = }"
+    )
+
+
+@bot.event
+async def on_command_error(ctx: commands.Context, error: commands.CommandError):
+    _log.error(
+        f"Failed to run command:"
+        f" {ctx.command = }; {ctx.message.author = }; {ctx.message.id = }",
+        exc_info=error,
+    )
+
+
+async def main():
+    _log.debug("Entered main()")
+
+    token = read_token_file()
+
+    async with bot:
+        await bot.start(token=token, reconnect=True)
+
+
+_log = setup_logging()
+_log.debug("Logging initialised")
+
+_log.debug(f"{sys.argv = }")
+_log.debug(f"{os.getcwd() = }")
+
+asyncio.run(main())