"""
Sends updates to a Telegram bot.

Usage:
>>> from tqdm.contrib.telegram import tqdm, trange
>>> for i in trange(10, token='{token}', chat_id='{chat_id}'):
...     ...

![screenshot](
https://raw.githubusercontent.com/tqdm/img/src/screenshot-telegram.gif)
"""
from __future__ import absolute_import

from os import getenv

from requests import Session

from tqdm.auto import tqdm as tqdm_auto
from tqdm.utils import _range

from .utils_worker import MonoWorker

__author__ = {"github.com/": ["casperdcl"]}
__all__ = ['TelegramIO', 'tqdm_telegram', 'ttgrange', 'tqdm', 'trange']


class TelegramIO(MonoWorker):
    """Non-blocking file-like IO using a Telegram Bot."""
    API = 'https://api.telegram.org/bot'

    def __init__(self, token, chat_id):
        """Creates a new message in the given `chat_id`."""
        super(TelegramIO, self).__init__()
        self.token = token
        self.chat_id = chat_id
        self.session = session = Session()
        self.text = self.__class__.__name__
        try:
            res = session.post(
                self.API + '%s/sendMessage' % self.token,
                data={'text': '`' + self.text + '`', 'chat_id': self.chat_id,
                      'parse_mode': 'MarkdownV2'})
        except Exception as e:
            tqdm_auto.write(str(e))
        else:
            self.message_id = res.json()['result']['message_id']

    def write(self, s):
        """Replaces internal `message_id`'s text with `s`."""
        if not s:
            s = "..."
        s = s.replace('\r', '').strip()
        if s == self.text:
            return  # avoid duplicate message Bot error
        self.text = s
        try:
            future = self.submit(
                self.session.post, self.API + '%s/editMessageText' % self.token,
                data={'text': '`' + s + '`', 'chat_id': self.chat_id,
                      'message_id': self.message_id, 'parse_mode': 'MarkdownV2'})
        except Exception as e:
            tqdm_auto.write(str(e))
        else:
            return future


class tqdm_telegram(tqdm_auto):
    """
    Standard `tqdm.auto.tqdm` but also sends updates to a Telegram Bot.
    May take a few seconds to create (`__init__`).

    - create a bot <https://core.telegram.org/bots#6-botfather>
    - copy its `{token}`
    - add the bot to a chat and send it a message such as `/start`
    - go to <https://api.telegram.org/bot`{token}`/getUpdates> to find out
      the `{chat_id}`
    - paste the `{token}` & `{chat_id}` below

    >>> from tqdm.contrib.telegram import tqdm, trange
    >>> for i in tqdm(iterable, token='{token}', chat_id='{chat_id}'):
    ...     ...
    """
    def __init__(self, *args, **kwargs):
        """
        Parameters
        ----------
        token  : str, required. Telegram token
            [default: ${TQDM_TELEGRAM_TOKEN}].
        chat_id  : str, required. Telegram chat ID
            [default: ${TQDM_TELEGRAM_CHAT_ID}].

        See `tqdm.auto.tqdm.__init__` for other parameters.
        """
        kwargs = kwargs.copy()
        self.tgio = TelegramIO(kwargs.pop('token', getenv('TQDM_TELEGRAM_TOKEN')),
                               kwargs.pop('chat_id', getenv('TQDM_TELEGRAM_CHAT_ID')))
        super(tqdm_telegram, self).__init__(*args, **kwargs)

    def display(self, **kwargs):
        super(tqdm_telegram, self).display(**kwargs)
        fmt = self.format_dict
        if fmt.get('bar_format', None):
            fmt['bar_format'] = fmt['bar_format'].replace(
                '<bar/>', '{bar:10u}').replace('{bar}', '{bar:10u}')
        else:
            fmt['bar_format'] = '{l_bar}{bar:10u}{r_bar}'
        self.tgio.write(self.format_meter(**fmt))

    def clear(self, *args, **kwargs):
        super(tqdm_telegram, self).clear(*args, **kwargs)
        self.tgio.write("")


def ttgrange(*args, **kwargs):
    """
    A shortcut for `tqdm.contrib.telegram.tqdm(xrange(*args), **kwargs)`.
    On Python3+, `range` is used instead of `xrange`.
    """
    return tqdm_telegram(_range(*args), **kwargs)


# Aliases
tqdm = tqdm_telegram
trange = ttgrange
