import re
import logging
import asyncio

from settings import TELEGRAM_API_TOKEN, TELEGRAM_CHAT_ID
from db import Database
from util import make_session

logger = logging.getLogger(__name__)

TELEGRAM_API_URL = 'https://api.telegram.org/bot'

class Telegram:
  def __init__(self, aiosession):
    if TELEGRAM_API_TOKEN is None:
      raise Exception("TELEGRAM_API_TOKEN is required")
    
    self.aiosession = aiosession

  async def get(self, request, params):
    async with self.aiosession.get('{}{}/{}'.format(
      TELEGRAM_API_URL,
      TELEGRAM_API_TOKEN,
      request
    ), params=params) as response:
      if not response.ok:
        logger.error('{} {}'.format(request, response.status))
        raise Exception('{} {}'.format(request, response.status))

      return await response.json()

  async def post(self, request, data):
    async with self.aiosession.post('{}{}/{}'.format(
      TELEGRAM_API_URL,
      TELEGRAM_API_TOKEN,
      request
    ), json=data) as response:
      if not response.ok:
        logger.error('{} {}'.format(request, response.status))
        raise Exception('{} {}'.format(request, response.status))
      
      return await response.json()
    
  async def message_send(self, text):
    data = {
      'chat_id': TELEGRAM_CHAT_ID,
      'text': text
    }

    return await self.post('sendMessage', data=data)
  
  async def updates_get(self, offset=0, timeout=240):
    return await self.get('getUpdates', params={
      'offset': offset,
      'timeout': timeout
    })

class TelegramCommand():
  command_regex = None
  command_text = None
  authorized = True

  def matches(self, text):
    return (
      (self.command_text is not None and text.startswith(self.command_text)) or
      (self.command_regex is not None and self.command_regex.match(text) is not None)
    )

  async def exec(self, text, update, session):
    pass

class SkipDayAddCommand(TelegramCommand):
  command_regex = re.compile(r"^\/skip_day( (?P<date>\d{4}-\d{2}-\d{2}))?$")

  async def exec(self, text, update, session):
    date_str = text.split(' ')[1]

    db = Database()
    db.skip_day_put(date_str)

    yield f"Added skip day {date_str}"

commands = [
  SkipDayAddCommand()
]

async def do_reply(data, t):
  if(type(data) is str):
    await t.message_send(
      data
    )

async def handle_commands(commands=commands):
  async with make_session() as session:
    t = Telegram(session)

    offset = 0
    while True:
      try:
        updates = await t.updates_get(offset=offset)

        if(updates['ok']):
          for update in updates['result']:
            if('message' in update):
              chat_id = update['message']['chat']['id']

              if(chat_id != TELEGRAM_CHAT_ID):
                continue

              for command in commands:
                if(command.matches(update['message']['text'])):
                  try:
                    result = command.exec(update['message']['text'], update, session)

                    if result.__class__.__name__ == 'async_generator':
                      async for r in result:
                        await do_reply(r, t)
                    else:
                      await do_reply(await result, t)
                  except:
                    await t.message_send('There was a problem with your command')
                    logger.exception('Problem while executing a command')

                  break
            offset = update['update_id'] + 1
        else:
          logger.warning("getUpdates was not ok {}".format(update))
          await asyncio.sleep(30)
      except Exception as e:
        logger.exception("getUpdates exception {}".format(e))
        await asyncio.sleep(30)