import logging
from datetime import timedelta

import arrow
from telegram.error import NetworkError
from telegram.ext import CommandHandler, Updater
from telegram import ParseMode, Bot, Update
from wrapt import synchronized

from persistence import Trade, Session
from exchange import get_exchange_api
from utils import get_conf

# Remove noisy log messages
logging.getLogger('requests.packages.urllib3').setLevel(logging.INFO)
logging.getLogger('telegram').setLevel(logging.INFO)
logger = logging.getLogger(__name__)

_updater = None

conf = get_conf()
api_wrapper = get_exchange_api(conf)


def authorized_only(command_handler):
    """
    Decorator to check if the message comes from the correct chat_id
    :param command_handler: Telegram CommandHandler
    :return: decorated function
    """
    def wrapper(*args, **kwargs):
        bot, update = args[0], args[1]
        if not isinstance(bot, Bot) or not isinstance(update, Update):
            raise ValueError('Received invalid Arguments: {}'.format(*args))

        chat_id = int(conf['telegram']['chat_id'])
        if int(update.message.chat_id) == chat_id:
            logger.info('Executing handler: {} for chat_id: {}'.format(command_handler.__name__, chat_id))
            return command_handler(*args, **kwargs)
        else:
            logger.info('Rejected unauthorized message from: {}'.format(update.message.chat_id))
    return wrapper


class TelegramHandler(object):
    @staticmethod
    @authorized_only
    def _status(bot, update):
        """
        Handler for /status.
        Returns the current TradeThread status
        :param bot: telegram bot
        :param update: message update
        :return: None
        """
        # Fetch open trade
        trades = Trade.query.filter(Trade.is_open.is_(True)).all()
        from main import get_instance
        if not get_instance().is_alive():
            TelegramHandler.send_msg('*Status:* `trader stopped`', bot=bot)
        elif not trades:
            TelegramHandler.send_msg('*Status:* `no active order`', bot=bot)
        else:
            for trade in trades:
                # calculate profit and send message to user
                current_rate = api_wrapper.get_ticker(trade.pair)['bid']
                current_profit = 100 * ((current_rate - trade.open_rate) / trade.open_rate)
                orders = api_wrapper.get_open_orders(trade.pair)
                orders = [o for o in orders if o['id'] == trade.open_order_id]
                order = orders[0] if orders else None
                message = """
*Current Pair:* [{pair}](https://bittrex.com/Market/Index?MarketName={pair})
*Open Since:* `{date}`
*Amount:* `{amount}`
*Open Rate:* `{open_rate}`
*Close Rate:* `{close_rate}`
*Current Rate:* `{current_rate}`
*Close Profit:* `{close_profit}`
*Current Profit:* `{current_profit}%`
*Open Order:* `{open_order}`
                        """.format(
                    pair=trade.pair.replace('_', '-'),
                    date=arrow.get(trade.open_date).humanize(),
                    open_rate=trade.open_rate,
                    close_rate=trade.close_rate,
                    current_rate=current_rate,
                    amount=round(trade.amount, 8),
                    close_profit='{}%'.format(round(trade.close_profit, 2)) if trade.close_profit else None,
                    current_profit=round(current_profit, 2),
                    open_order='{} ({})'.format(order['remaining'], order['type']) if order else None,
                )
                TelegramHandler.send_msg(message, bot=bot)

    @staticmethod
    @authorized_only
    def _profit(bot, update):
        """
        Handler for /profit.
        Returns a cumulative profit statistics.
        :param bot: telegram bot
        :param update: message update
        :return: None
        """
        trades = Trade.query.filter(Trade.is_open.is_(False)).all()
        trade_count = len(trades)
        profit_amount = sum((t.close_profit / 100) * t.btc_amount for t in trades)
        profit = sum(t.close_profit for t in trades)
        avg_stake_amount = sum(t.btc_amount for t in trades) / float(trade_count)
        durations_hours = [(t.close_date - t.open_date).total_seconds() / 3600.0 for t in trades]
        avg_duration = sum(durations_hours) / float(len(durations_hours))
        markdown_msg = """
*Total Profit:* `{profit_btc} BTC ({profit}%)`
*Trade Count:* `{trade_count}`
*First Action:* `{first_trade_date}`
*Latest Action:* `{latest_trade_date}`
*Avg. Stake Amount:* `{avg_open_amount} BTC`
*Avg. Duration:* `{avg_duration}` 
    """.format(
            profit_btc=round(profit_amount, 8),
            profit=round(profit, 2),
            trade_count=trade_count,
            first_trade_date=arrow.get(trades[0].open_date).humanize(),
            latest_trade_date=arrow.get(trades[-1].open_date).humanize(),
            avg_open_amount=round(avg_stake_amount, 8),
            avg_duration=str(timedelta(hours=avg_duration)).split('.')[0],
        )
        TelegramHandler.send_msg(markdown_msg, bot=bot)

    @staticmethod
    @authorized_only
    def _start(bot, update):
        """
        Handler for /start.
        Starts TradeThread
        :param bot: telegram bot
        :param update: message update
        :return: None
        """
        from main import get_instance
        if get_instance().is_alive():
            TelegramHandler.send_msg('*Status:* `already running`', bot=bot)
        else:
            get_instance(recreate=True).start()

    @staticmethod
    @authorized_only
    def _stop(bot, update):
        """
        Handler for /stop.
        Stops TradeThread
        :param bot: telegram bot
        :param update: message update
        :return: None
        """
        from main import get_instance, stop_instance
        if get_instance().is_alive():
            TelegramHandler.send_msg('`Stopping trader ...`', bot=bot)
            stop_instance()
        else:
            TelegramHandler.send_msg('*Status:* `already stopped`', bot=bot)

    @staticmethod
    @authorized_only
    def _cancel(bot, update):
        """
        Handler for /cancel.
        Cancels the open order for the current Trade.
        :param bot: telegram bot
        :param update: message update
        :return: None
        """
        # TODO: make compatible with max_open_orders
        TelegramHandler.send_msg('`Currently not implemented`')
        return

        trade = Trade.query.filter(Trade.is_open.is_(True)).first()
        if not trade:
            TelegramHandler.send_msg('`There is no open trade`')
            return

        order_id = trade.open_order_id
        if not order_id:
            TelegramHandler.send_msg('`There is no open order`')
            return

        api_wrapper.cancel_order(order_id)
        trade.open_order_id = None
        trade.close_rate = None
        trade.close_date = None
        trade.close_profit = None
        Session.flush()
        TelegramHandler.send_msg('*Order cancelled:* `{}`'.format(order_id), bot=bot)
        logger.info('Order cancelled: (order_id: {})'.format(order_id))

    @staticmethod
    @synchronized
    def get_updater(conf):
        """
        Returns the current telegram updater instantiates a new one
        :param conf:
        :return: telegram.ext.Updater
        """
        global _updater
        if not _updater:
            _updater = Updater(token=conf['telegram']['token'], workers=0)
        return _updater

    @staticmethod
    def listen():
        """
        Registers all known command handlers and starts polling for message updates
        :return: None
        """
        # Register command handler and start telegram message polling
        handles = [
            CommandHandler('status', TelegramHandler._status),
            CommandHandler('profit', TelegramHandler._profit),
            CommandHandler('start', TelegramHandler._start),
            CommandHandler('stop', TelegramHandler._stop),
            CommandHandler('cancel', TelegramHandler._cancel),
        ]
        for handle in handles:
            TelegramHandler.get_updater(conf).dispatcher.add_handler(handle)
        TelegramHandler.get_updater(conf).start_polling(clean=True, bootstrap_retries=3)
        logger.info('TelegramHandler is listening for following commands: {}'
                    .format([h.command for h in handles]))

    @staticmethod
    def send_msg(msg, bot=None):
        """
        Send given markdown message
        :param msg: message
        :param bot: alternative bot
        :return: None
        """
        if conf['telegram'].get('enabled', False):
            bot = bot or TelegramHandler.get_updater(conf).bot
            try:
                bot.send_message(conf['telegram']['chat_id'], msg, parse_mode=ParseMode.MARKDOWN)
            except NetworkError as e:
                logger.warning('Got Telegram NetworkError: {}! trying one more time'.format(e.message))
                bot.send_message(conf['telegram']['chat_id'], msg, parse_mode=ParseMode.MARKDOWN)
            except Exception:
                logger.exception('Exception occurred within Telegram API')