#!/usr/bin/env python

import sys
import json
import datetime
import os
import os.path
import functools
import contextlib
import asyncio
import concurrent
import logging
import selectors

from mattermostdriver import Driver, Websocket # pip install mattermostdriver

import config


logging.basicConfig(level='INFO')


class MatterLog:

	__slots__ = ['driver', 'logdir']

	def __init__(self, driver, loop, logdir):
		self.driver = driver
		self.logdir = logdir

	@contextlib.contextmanager
	def channel_file(self, team, channel):
		current = os.path.join(self.logdir, team, channel, 'current')
		os.makedirs(os.path.dirname(current), exist_ok=True)
		with open(current, 'a') as f:
			yield f

	async def __call__(self, event):
		event = json.loads(event)
		if 'event' not in event:
			logging.warning('received none-event: ' + str(event))
		elif event['event'] in MatterLog.IGNORED_EVENTS:
			pass
		elif not hasattr(self, 'handle_' + event['event']):
			logging.warning('no handler for event: ' + str(event))
		else:
			await getattr(self, 'handle_' + event['event'])(event['data'])

	IGNORED_EVENTS = { 'emoji_added', 'hello', 'license_changed',
		'preference_changed', 'preferences_changed', 'preferences_deleted',
		'typing' }

	async def handle_posted(self, data):
		post = json.loads(data['post'])
		with self.channel_file(self.cached_team_name(data['team_id']), data['channel_name']) as f:
			if post.get('root_id'):
				print(post['create_at'], post['id'], 'REPLY', post['original_id'], data['sender_name'][1:], post['message'], sep='\t', file=f)
			else:
				print(post['create_at'], post['id'], 'MSG', data['sender_name'][1:], post['message'], sep='\t', file=f)

	@functools.lru_cache
	def cached_team_name(self, team):
		return self.driver.teams.get_team(team)['name']


async def messageloop(driver, loop, logdir):
	selector = selectors.DefaultSelector()
	for team in driver.teams.get_teams():
		for channel in driver.channels.get_channels_for_user(driver.client.userid, team['id']):
			sayfile = os.path.join(logdir, team['name'], channel['name'], 'say')

			if os.path.exists(sayfile): os.unlink(sayfile)
			os.makedirs(os.path.dirname(sayfile), exist_ok=True)
			os.mkfifo(sayfile)
			f = os.open(sayfile, os.O_RDONLY | os.O_NONBLOCK)
			selector.register(f, selectors.EVENT_READ, (sayfile, channel['id']))

	while True:
		events = await loop.run_in_executor(None, lambda: selector.select())
		for key, mask in events:
			selector.unregister(key.fileobj)
			message = os.read(key.fileobj, 1024)
			os.close(key.fileobj)
			if message:
				driver.posts.create_post(options={
					'channel_id': key.data[1],
					'message': message.decode()
				})
			f = os.open(key.data[0], os.O_RDONLY | os.O_NONBLOCK)
			selector.register(f, selectors.EVENT_READ, key.data)


if __name__ == '__main__':

	driver = Driver(config.driver)
	driver.login()

	def listen(driver):
		websocket = Websocket(driver.options, driver.client.token)
		loop = asyncio.get_event_loop()
		loop.set_debug(True)
		loop.create_task(messageloop(driver, loop, config.logdir))
		loop.run_until_complete(websocket.connect(MatterLog(driver, loop, config.logdir)))