import aiohttp
import aiohttp.web
import argparse
import asyncio
import collections
import concurrent.futures
import json
import logging
import signal


logging.basicConfig(level = logging.DEBUG, format = '{asctime} {levelname} {message}', style = '{')


class MessageQueue:
	# An object holding onto the messages received from nodeping
	# This is effectively a reimplementation of parts of asyncio.Queue with some specific additional code.
	# Unfortunately, asyncio.Queue's extensibility (_init, _put, and _get methods) is undocumented, so I don't want to rely on that.
	# Differences to asyncio.Queue include:
	#  - No maxsize
	#  - No put coroutine (not necessary since the queue can never be full)
	#  - Only one concurrent getter
	#  - putleft_nowait to put to the front of the queue (so that the IRC client can put a message back when delivery fails)

	def __init__(self):
		self._getter = None  # None | asyncio.Future
		self._queue = collections.deque()

	async def get(self):
		if self._getter is not None:
			raise RuntimeError('Cannot get concurrently')
		if len(self._queue) == 0:
			self._getter = asyncio.get_running_loop().create_future()
			logging.debug('Awaiting getter')
			try:
				await self._getter
			except asyncio.CancelledError:
				logging.debug('Cancelled getter')
				self._getter = None
				raise
			logging.debug('Awaited getter')
			self._getter = None
		# For testing the cancellation/putting back onto the queue
		#logging.debug('Delaying message queue get')
		#await asyncio.sleep(3)
		#logging.debug('Done delaying')
		return self.get_nowait()

	def get_nowait(self):
		if len(self._queue) == 0:
			raise asyncio.QueueEmpty
		return self._queue.popleft()

	def put_nowait(self, item):
		self._queue.append(item)
		if self._getter is not None:
			self._getter.set_result(None)

	def putleft_nowait(self, item):
		self._queue.appendleft(item)
		if self._getter is not None:
			self._getter.set_result(None)

	def qsize(self):
		return len(self._queue)


class IRCClientProtocol(asyncio.Protocol):
	def __init__(self, messageQueue, stopEvent, loop, nick, real, channel):
		logging.debug(f'Protocol init {id(self)}: {messageQueue} {id(messageQueue)}, {stopEvent}, {loop}')
		self.messageQueue = messageQueue
		self.stopEvent = stopEvent
		self.loop = loop
		self.nick = nick
		self.real = real
		self.channel = channel
		self.channelb = channel.encode('utf-8')
		self.buffer = b''
		self.connected = False

	def send(self, data):
		logging.info(f'Send: {data!r}')
		self.transport.write(data + b'\r\n')

	def connection_made(self, transport):
		logging.info('Connected')
		self.transport = transport
		self.connected = True
		nickb = self.nick.encode('utf-8')
		self.send(b'NICK ' + nickb)
		self.send(b'USER ' + nickb + b' ' + nickb + b' ' + nickb + b' :' + self.real.encode('utf-8'))
		self.send(b'JOIN ' + self.channelb)
		asyncio.create_task(self.send_messages())

	async def _get_message(self):
		logging.debug(f'Message queue {id(self.messageQueue)} length: {self.messageQueue.qsize()}')
		messageFuture = asyncio.create_task(self.messageQueue.get())
		done, pending = await asyncio.wait((messageFuture, self.stopEvent.wait()), return_when = concurrent.futures.FIRST_COMPLETED)
		if self.stopEvent.is_set():
			if messageFuture in pending:
				logging.debug('Cancelling messageFuture')
				messageFuture.cancel()
				try:
					await messageFuture
				except asyncio.CancelledError:
					logging.debug('Cancelled messageFuture')
					pass
			else:
				# messageFuture is already done but we're stopping, so put the result back onto the queue
				self.messageQueue.putleft_nowait(messageFuture.result())
			return None
		assert messageFuture in done, 'Invalid state: messageFuture not in done futures'
		return messageFuture.result()

	async def send_messages(self):
		while self.connected:
			logging.debug(f'{id(self)}: trying to get a message')
			message = await self._get_message()
			logging.debug(f'{id(self)}: got message: {message!r}')
			if message is None:
				break
			self.send(b'PRIVMSG ' + self.channelb + b' :' + message.encode('utf-8'))
			#TODO self.messageQueue.putleft_nowait if delivery fails
			await asyncio.sleep(1) # Rate limit

	def data_received(self, data):
		logging.debug(f'Data received: {data!r}')
		# Split received data on CRLF. If there's any data left in the buffer, prepend it to the first message and process that.
		# Then, process all messages except the last one (since data might not end on a CRLF) and keep the remainder in the buffer.
		# If data does end with CRLF, all messages will have been processed and the buffer will be empty again.
		messages = data.split(b'\r\n')
		if self.buffer:
			self.message_received(self.buffer + messages[0])
			messages = messages[1:]
		for message in messages[:-1]:
			self.message_received(message)
		self.buffer = messages[-1]

	def message_received(self, message):
		logging.info(f'Message received: {message!r}')
		if message.startswith(b'PING '):
			self.send(b'PONG ' + message[5:])

	def connection_lost(self, exc):
		logging.info('The server closed the connection')
		self.connected = False
		self.stopEvent.set()


class WebServer:
	def __init__(self, messageQueue, host, port, auth):
		self.messageQueue = messageQueue
		self.host = host
		self.port = port
		self.auth = auth
		if auth:
			self.authHeader = f'Basic {base64.b64encode(auth.encode("utf-8")).decode("utf-8")}'
		self._app = aiohttp.web.Application()
		self._app.add_routes([aiohttp.web.post('/nodeping', self.nodeping_post)])

	async def run(self, stopEvent):
		runner = aiohttp.web.AppRunner(self._app)
		await runner.setup()
		site = aiohttp.web.TCPSite(runner, self.host, self.port)
		await site.start()
		await stopEvent.wait()
		await runner.cleanup()

	async def nodeping_post(self, request):
		logging.info(f'Received request with data: {await request.read()!r}')
		authHeader = request.headers.get('Authorization')
		if self.auth and (not authHeader or authHeader != self.authHeader):
			return aiohttp.web.HTTPForbidden()
		try:
			data = await request.json()
		except (aiohttp.ContentTypeError, json.JSONDecodeError) as e:
			logging.error(f'Received invalid data: {await request.read()!r}')
			return aiohttp.web.HTTPBadRequest()
		if 'message' not in data:
			logging.error(f'Received invalid data: {await request.read()!r}')
			return aiohttp.web.HTTPBadRequest()
		if '\r' in data['message'] or '\n' in data['message']:
			logging.error(f'Received invalid data: {await request.read()!r}')
			return aiohttp.web.HTTPBadRequest()
		logging.debug(f'Putting to message queue {id(self.messageQueue)}')
		self.messageQueue.put_nowait(data['message'])
		return aiohttp.web.HTTPOk()


async def run_irc(loop, messageQueue, sigintEvent, host, port, ssl, nick, real, channel):
	stopEvent = asyncio.Event()
	while True:
		stopEvent.clear()
		try:
			transport, protocol = await loop.create_connection(lambda: IRCClientProtocol(messageQueue, stopEvent, loop, nick = nick, real = real, channel = channel), host, port, ssl = ssl)
			try:
				await asyncio.wait((stopEvent.wait(), sigintEvent.wait()), return_when = concurrent.futures.FIRST_COMPLETED)
			finally:
				transport.close()
		except (ConnectionRefusedError, asyncio.TimeoutError) as e:
			logging.error(str(e))
		await asyncio.wait((asyncio.sleep(5), sigintEvent.wait()), return_when = concurrent.futures.FIRST_COMPLETED)
		if sigintEvent.is_set():
			break


async def run_webserver(loop, messageQueue, sigintEvent, host, port, auth):
	server = WebServer(messageQueue, host, port, auth)
	await server.run(sigintEvent)


def parse_args():
	parser = argparse.ArgumentParser(formatter_class = argparse.ArgumentDefaultsHelpFormatter)
	parser.add_argument('--irchost', type = str, help = 'IRC server hostname', default = 'irc.hackint.org')
	parser.add_argument('--ircport', type = int, help = 'IRC server port', default = 6697)
	parser.add_argument('--ircssl', choices = ['yes', 'no', 'insecure'], help = 'enable, disable, or use insecure SSL/TLS', default = 'yes')
	parser.add_argument('--ircnick', help = 'IRC nickname', default = 'npbot')
	parser.add_argument('--ircreal', help = 'IRC realname', default = 'I am a bot.')
	parser.add_argument('--ircchannel', help = 'IRC channel to join and post messages', default = '#nodeping')
	parser.add_argument('--webhost', type = str, help = 'web server host to bind to', default = '127.0.0.1')
	parser.add_argument('--webport', type = int, help = 'web server port to bind to', default = 8080)
	parser.add_argument('--webauth', type = str, help = 'basic auth data (user:pass, or None to disable the check)', default = None)
	return parser.parse_args()


async def main():
	args = parse_args()
	ssl = {'yes': True, 'no': False, 'insecure': ssl.SSLContext()}[args.ircssl]

	loop = asyncio.get_running_loop()

	messageQueue = MessageQueue()
	sigintEvent = asyncio.Event()

	def sigint_callback():
		logging.info('Got SIGINT')
		nonlocal sigintEvent
		sigintEvent.set()
	loop.add_signal_handler(signal.SIGINT, sigint_callback)

	irc = run_irc(loop, messageQueue, sigintEvent, host = args.irchost, port = args.ircport, ssl = ssl, nick = args.ircnick, real = args.ircreal, channel = args.ircchannel)
	webserver = run_webserver(loop, messageQueue, sigintEvent, host = args.webhost, port = args.webport, auth = args.webauth)
	await asyncio.gather(irc, webserver)


asyncio.run(main())