import re
from datetime import datetime, timedelta
from discord import Message
from discord.ext import commands

from cogs.basecog import BaseCog, BotMessage
from config import CONFIG
from rbutils import parse_timedelta, describe_timedelta
from storage import ConfigKey, Storage

class GeneralCog(BaseCog, name='General'):
	"""
	Cog for handling high-level bot functionality and commands. Should be the
	first cog added to the bot.
	"""
	def __init__(self, bot: commands.Bot):
		super().__init__(bot)
		self.is_connected = False
		self.is_ready = False

	@commands.Cog.listener()
	async def on_connect(self):
		'Event handler'
		print('on_connect')
		self.is_connected = True

	@commands.Cog.listener()
	async def on_ready(self):
		'Event handler'
		print('on_ready')
		self.is_ready = True

	@commands.command(
		brief='Posts a test warning',
		description='Tests whether a warning channel is configured for this ' + \
			'guild by posting a test warning. If a mod mention is ' + \
			'configured, that user/role will be tagged in the test warning.',
	)
	@commands.has_permissions(ban_members=True)
	@commands.guild_only()
	async def testwarn(self, context):
		'Command handler'
		if Storage.get_config_value(context.guild, ConfigKey.WARNING_CHANNEL_ID) is None:
			await context.message.reply(
				f'{CONFIG["warning_emoji"]} No warning channel set!',
				mention_author=False)
		else:
			bm = BotMessage(
				context.guild,
				f'Test warning message (requested by {context.author.name})',
				type=BotMessage.TYPE_MOD_WARNING)
			await self.post_message(bm)

	@commands.command(
		brief='Simple test reply',
		description='Replies to the command message. Useful to ensure the ' + \
			'bot is working properly.',
	)
	async def hello(self, context):
		'Command handler'
		await context.message.reply(
			f'Hey, {context.author.name}!',
		 	mention_author=False)

	@commands.command(
		brief='Shuts down the bot',
		description='Causes the bot script to terminate. Only usable by a ' + \
			'user with server admin permissions.',
	)
	@commands.has_permissions(administrator=True)
	@commands.guild_only()
	async def shutdown(self, context: commands.Context):
		'Command handler'
		await context.message.add_reaction('👋')
		await self.bot.close()

	@commands.command(
		brief='Mass deletes messages',
		description='Deletes recent messages by the given user. The user ' +
			'can be either an @ mention or a numeric user ID. The age is ' +
			'a duration, such as "30s", "5m", "1h30m". Only the most ' +
			'recent 100 messages in each channel are searched.',
		usage='<user:id|mention> <age:timespan>'
	)
	@commands.has_permissions(manage_messages=True)
	@commands.guild_only()
	async def deletemessages(self, context, user: str, age: str) -> None:
		'Command handler'
		member_id = self.__parse_member_id(user)
		if member_id is None:
			await context.message.reply(
				f'{CONFIG["failure_emoji"]} user must be a mention or numeric user id',
				mention_author=False)
			return
		try:
			age_delta: timedelta = parse_timedelta(age)
		except ValueError:
			await context.message.reply(
				f'{CONFIG["failure_emoji"]} age must be a timespan, like "30s", "10m", "1h30m"',
				mention_author=False)
			return
		cutoff: datetime = datetime.utcnow() - age_delta
		def predicate(message: Message) -> bool:
			return str(message.author.id) == member_id and message.created_at >= cutoff
		deleted_messages = []
		for channel in context.guild.text_channels:
			try:
				deleted_messages += await channel.purge(limit=100, check=predicate)
			except:
				# XXX: Sloppily glossing over access errors instead of checking access
				pass
		await context.message.reply(
			f'{CONFIG["success_emoji"]} Deleted {len(deleted_messages)} ' + \
			f'messages by <@!{member_id}> from the past {describe_timedelta(age_delta)}.',
			mention_author=False)

	def __parse_member_id(self, arg: str) -> str:
		p = re.compile('^<@!?([0-9]+)>$')
		m = p.match(arg)
		if m:
			return m.group(1)
		p = re.compile('^([0-9]+)$')
		m = p.match(arg)
		if m:
			return m.group(1)
		return None