# pragma pylint: disable=W0603
""" Cryptocurrency Exchanges support """
import logging
from random import randint
from typing import List, Dict, Any, Optional
from datetime import datetime

import ccxt
import ccxt.async_support as ccxt_async
import arrow
import asyncio

from freqtrade import constants, OperationalException, DependencyException, TemporaryError

logger = logging.getLogger(__name__)

API_RETRY_COUNT = 4


# Urls to exchange markets, insert quote and base with .format()
_EXCHANGE_URLS = {
    ccxt.bittrex.__name__: '/Market/Index?MarketName={quote}-{base}',
    ccxt.binance.__name__: '/tradeDetail.html?symbol={base}_{quote}'
}


def retrier(f):
    def wrapper(*args, **kwargs):
        count = kwargs.pop('count', API_RETRY_COUNT)
        try:
            return f(*args, **kwargs)
        except (TemporaryError, DependencyException) as ex:
            logger.warning('%s() returned exception: "%s"', f.__name__, ex)
            if count > 0:
                count -= 1
                kwargs.update({'count': count})
                logger.warning('retrying %s() still for %s times', f.__name__, count)
                return wrapper(*args, **kwargs)
            else:
                logger.warning('Giving up retrying: %s()', f.__name__)
                raise ex
    return wrapper


def run_async_task(f, **kwargs):
    """
    Run async task and its kwargs.
    Usage:
          run_async_task(async_f, arg1='foo', arg2='bar')
    """
    logger.info('Running async task method %s with args %s', f, kwargs)
    return asyncio.get_event_loop().run_until_complete(f(**kwargs))


class Exchange(object):

    # Current selected exchange
    _api: ccxt.Exchange = None
    _api_async: ccxt_async.Exchange = None
    _conf: Dict = {}
    _cached_ticker: Dict[str, Any] = {}

    # Holds all open sell orders for dry_run
    _dry_run_open_orders: Dict[str, Any] = {}

    def __init__(self, config: dict) -> None:
        """
        Initializes this module with the given config,
        it does basic validation whether the specified
        exchange and pairs are valid.
        :return: None
        """
        self._conf.update(config)

        if config['dry_run']:
            logger.info('Instance is running with dry_run enabled')

        exchange_config = config['exchange']
        self._api = self._init_ccxt(exchange_config)
        self._api_async = self._init_ccxt(exchange_config, ccxt_async)

        logger.info('Using Exchange "%s"', self.name)

        # Check if all pairs are available
        self.validate_pairs(config['exchange']['pair_whitelist'])

        if config.get('ticker_interval'):
            # Check if timeframe is available
            self.validate_timeframes(config['ticker_interval'])

        self.__loop = None
        self._ticker_history = {}
        self._fetching_progress = False
        for _pair in config['exchange']['pair_whitelist']:
            print(f'initting {_pair} for history cache')
            self._ticker_history[_pair] = {}
        logger.info('Ticker_history cache for given pairs%s', self._ticker_history)

    @property
    def loop(self):
        return self.__loop

    @loop.setter
    def loop(self, loop):
        if not self.__loop:
            logger.info('** Setting exchange asyncio loop **')
            self.__loop = loop

    def _init_ccxt(self, exchange_config: dict, ccxt_module=ccxt) -> ccxt.Exchange:
        """
        Initialize ccxt with given config and return valid
        ccxt instance.
        """
        # Find matching class for the given exchange name
        name = exchange_config['name']

        if name not in ccxt_module.exchanges:
            raise OperationalException(f'Exchange {name} is not supported')
        try:
            api = getattr(ccxt_module, name.lower())({
                'apiKey': exchange_config.get('key'),
                'secret': exchange_config.get('secret'),
                'password': exchange_config.get('password'),
                'uid': exchange_config.get('uid', ''),
                'enableRateLimit': True,
            })
        except (KeyError, AttributeError):
            raise OperationalException(f'Exchange {name} is not supported')

        return api

    @property
    def name(self) -> str:
        """exchange Name (from ccxt)"""
        return self._api.name

    @property
    def id(self) -> str:
        """exchange ccxt id"""
        return self._api.id

    def validate_pairs(self, pairs: List[str]) -> None:
        """
        Checks if all given pairs are tradable on the current exchange.
        Raises OperationalException if one pair is not available.
        :param pairs: list of pairs
        :return: None
        """

        try:
            markets = self._api.load_markets()
        except ccxt.BaseError as e:
            logger.warning('Unable to validate pairs (assuming they are correct). Reason: %s', e)
            return

        stake_cur = self._conf['stake_currency']
        for pair in pairs:
            # Note: ccxt has BaseCurrency/QuoteCurrency format for pairs
            # TODO: add a support for having coins in BTC/USDT format
            if not pair.endswith(stake_cur):
                raise OperationalException(
                    f'Pair {pair} not compatible with stake_currency: {stake_cur}')
            if pair not in markets:
                raise OperationalException(
                    f'Pair {pair} is not available at {self.name}')

    def validate_timeframes(self, timeframe: List[str]) -> None:
        """
        Checks if ticker interval from config is a supported timeframe on the exchange
        """
        timeframes = self._api.timeframes
        if timeframe not in timeframes:
            raise OperationalException(
                f'Invalid ticker {timeframe}, this Exchange supports {timeframes}')

    def exchange_has(self, endpoint: str) -> bool:
        """
        Checks if exchange implements a specific API endpoint.
        Wrapper around ccxt 'has' attribute
        :param endpoint: Name of endpoint (e.g. 'fetchOHLCV', 'fetchTickers')
        :return: bool
        """
        return endpoint in self._api.has and self._api.has[endpoint]

    def buy(self, pair: str, rate: float, amount: float) -> Dict:
        if self._conf['dry_run']:
            order_id = f'dry_run_buy_{randint(0, 10**6)}'
            self._dry_run_open_orders[order_id] = {
                'pair': pair,
                'price': rate,
                'amount': amount,
                'type': 'limit',
                'side': 'buy',
                'remaining': 0.0,
                'datetime': arrow.utcnow().isoformat(),
                'status': 'closed',
                'fee': None
            }
            return {'id': order_id}

        try:
            return self._api.create_limit_buy_order(pair, amount, rate)
        except ccxt.InsufficientFunds as e:
            raise DependencyException(
                f'Insufficient funds to create limit buy order on market {pair}.'
                f'Tried to buy amount {amount} at rate {rate} (total {rate*amount}).'
                f'Message: {e}')
        except ccxt.InvalidOrder as e:
            raise DependencyException(
                f'Could not create limit buy order on market {pair}.'
                f'Tried to buy amount {amount} at rate {rate} (total {rate*amount}).'
                f'Message: {e}')
        except (ccxt.NetworkError, ccxt.ExchangeError) as e:
            raise TemporaryError(
                f'Could not place buy order due to {e.__class__.__name__}. Message: {e}')
        except ccxt.BaseError as e:
            raise OperationalException(e)

    def sell(self, pair: str, rate: float, amount: float) -> Dict:
        if self._conf['dry_run']:
            order_id = f'dry_run_sell_{randint(0, 10**6)}'
            self._dry_run_open_orders[order_id] = {
                'pair': pair,
                'price': rate,
                'amount': amount,
                'type': 'limit',
                'side': 'sell',
                'remaining': 0.0,
                'datetime': arrow.utcnow().isoformat(),
                'status': 'closed'
            }
            return {'id': order_id}

        try:
            return self._api.create_limit_sell_order(pair, amount, rate)
        except ccxt.InsufficientFunds as e:
            raise DependencyException(
                f'Insufficient funds to create limit sell order on market {pair}.'
                f'Tried to sell amount {amount} at rate {rate} (total {rate*amount}).'
                f'Message: {e}')
        except ccxt.InvalidOrder as e:
            raise DependencyException(
                f'Could not create limit sell order on market {pair}.'
                f'Tried to sell amount {amount} at rate {rate} (total {rate*amount}).'
                f'Message: {e}')
        except (ccxt.NetworkError, ccxt.ExchangeError) as e:
            raise TemporaryError(
                f'Could not place sell order due to {e.__class__.__name__}. Message: {e}')
        except ccxt.BaseError as e:
            raise OperationalException(e)

    @retrier
    def get_balance(self, currency: str) -> float:
        if self._conf['dry_run']:
            return 999.9

        # ccxt exception is already handled by get_balances
        balances = self.get_balances()
        balance = balances.get(currency)
        if balance is None:
            raise TemporaryError(
                f'Could not get {currency} balance due to malformed exchange response: {balances}')
        return balance['free']

    @retrier
    def get_balances(self) -> dict:
        if self._conf['dry_run']:
            return {}

        try:
            balances = self._api.fetch_balance()
            # Remove additional info from ccxt results
            balances.pop("info", None)
            balances.pop("free", None)
            balances.pop("total", None)
            balances.pop("used", None)

            return balances
        except (ccxt.NetworkError, ccxt.ExchangeError) as e:
            raise TemporaryError(
                f'Could not get balance due to {e.__class__.__name__}. Message: {e}')
        except ccxt.BaseError as e:
            raise OperationalException(e)

    @retrier
    def get_tickers(self) -> Dict:
        try:
            return self._api.fetch_tickers()
        except ccxt.NotSupported as e:
            raise OperationalException(
                f'Exchange {self._api.name} does not support fetching tickers in batch.'
                f'Message: {e}')
        except (ccxt.NetworkError, ccxt.ExchangeError) as e:
            raise TemporaryError(
                f'Could not load tickers due to {e.__class__.__name__}. Message: {e}')
        except ccxt.BaseError as e:
            raise OperationalException(e)

    @retrier
    def get_ticker(self, pair: str, refresh: Optional[bool] = True) -> dict:
        if refresh or pair not in self._cached_ticker.keys():
            try:
                data = self._api.fetch_ticker(pair)
                try:
                    self._cached_ticker[pair] = {
                        'bid': float(data['bid']),
                        'ask': float(data['ask']),
                    }
                except KeyError:
                    logger.debug("Could not cache ticker data for %s", pair)
                return data
            except (ccxt.NetworkError, ccxt.ExchangeError) as e:
                raise TemporaryError(
                    f'Could not load ticker history due to {e.__class__.__name__}. Message: {e}')
            except ccxt.BaseError as e:
                raise OperationalException(e)
        else:
            logger.info("returning cached ticker-data for %s", pair)
            return self._cached_ticker[pair]

    async def get_ticker_history_async(self, tick_interval: str,
                                       since_ms: Optional[int] = None):
        """Fetch exchange ticker history for configured pairs"""
        if self._fetching_progress:
            return self._ticker_history

        data = []
        self._fetching_progress = True
        for _pair in self._ticker_history:
            logger.info('*'*20)
            logger.info('Async: Fetching history for pair %s', _pair)
            logger.info('*'*20)
            data = await self._api_async.fetch_ohlcv(_pair, timeframe=tick_interval)
            logger.info('Async data fetched len %s', len(data))
            print(f'***{_pair} Some data appears...... {data[0]}')
        return data

    @retrier
    def get_ticker_history(self, pair: str, tick_interval: str,
                           since_ms: Optional[int] = None) -> List[Dict]:
        try:
            # last item should be in the time interval [now - tick_interval, now]
            till_time_ms = arrow.utcnow().shift(
                            minutes=-constants.TICKER_INTERVAL_MINUTES[tick_interval]
                        ).timestamp * 1000
            # it looks as if some exchanges return cached data
            # and they update it one in several minute, so 10 mins interval
            # is necessary to skeep downloading of an empty array when all
            # chached data was already downloaded
            till_time_ms = min(till_time_ms, arrow.utcnow().shift(minutes=-10).timestamp * 1000)

            data: List[Dict[Any, Any]] = []
            while not since_ms or since_ms < till_time_ms:
                data_part = self._api.fetch_ohlcv(pair, timeframe=tick_interval, since=since_ms)

                # Because some exchange sort Tickers ASC and other DESC.
                # Ex: Bittrex returns a list of tickers ASC (oldest first, newest last)
                # when GDAX returns a list of tickers DESC (newest first, oldest last)
                data_part = sorted(data_part, key=lambda x: x[0])

                if not data_part:
                    break

                logger.debug('Downloaded data for %s time range [%s, %s]',
                             pair,
                             arrow.get(data_part[0][0] / 1000).format(),
                             arrow.get(data_part[-1][0] / 1000).format())

                data.extend(data_part)
                since_ms = data[-1][0] + 1

            return data
        except ccxt.NotSupported as e:
            raise OperationalException(
                f'Exchange {self._api.name} does not support fetching historical candlestick data.'
                f'Message: {e}')
        except (ccxt.NetworkError, ccxt.ExchangeError) as e:
            raise TemporaryError(
                f'Could not load ticker history due to {e.__class__.__name__}. Message: {e}')
        except ccxt.BaseError as e:
            raise OperationalException(f'Could not fetch ticker data. Msg: {e}')

    @retrier
    def cancel_order(self, order_id: str, pair: str) -> None:
        if self._conf['dry_run']:
            return

        try:
            return self._api.cancel_order(order_id, pair)
        except ccxt.InvalidOrder as e:
            raise DependencyException(
                f'Could not cancel order. Message: {e}')
        except (ccxt.NetworkError, ccxt.ExchangeError) as e:
            raise TemporaryError(
                f'Could not cancel order due to {e.__class__.__name__}. Message: {e}')
        except ccxt.BaseError as e:
            raise OperationalException(e)

    @retrier
    def get_order(self, order_id: str, pair: str) -> Dict:
        if self._conf['dry_run']:
            order = self._dry_run_open_orders[order_id]
            order.update({
                'id': order_id
            })
            return order
        try:
            return self._api.fetch_order(order_id, pair)
        except ccxt.InvalidOrder as e:
            raise DependencyException(
                f'Could not get order. Message: {e}')
        except (ccxt.NetworkError, ccxt.ExchangeError) as e:
            raise TemporaryError(
                f'Could not get order due to {e.__class__.__name__}. Message: {e}')
        except ccxt.BaseError as e:
            raise OperationalException(e)

    @retrier
    def get_trades_for_order(self, order_id: str, pair: str, since: datetime) -> List:
        if self._conf['dry_run']:
            return []
        if not self.exchange_has('fetchMyTrades'):
            return []
        try:
            my_trades = self._api.fetch_my_trades(pair, since.timestamp())
            matched_trades = [trade for trade in my_trades if trade['order'] == order_id]

            return matched_trades

        except ccxt.NetworkError as e:
            raise TemporaryError(
                f'Could not get trades due to networking error. Message: {e}')
        except ccxt.BaseError as e:
            raise OperationalException(e)

    def get_pair_detail_url(self, pair: str) -> str:
        try:
            url_base = self._api.urls.get('www')
            base, quote = pair.split('/')

            return url_base + _EXCHANGE_URLS[self._api.id].format(base=base, quote=quote)
        except KeyError:
            logger.warning('Could not get exchange url for %s', self.name)
            return ""

    @retrier
    def get_markets(self) -> List[dict]:
        try:
            return self._api.fetch_markets()
        except (ccxt.NetworkError, ccxt.ExchangeError) as e:
            raise TemporaryError(
                f'Could not load markets due to {e.__class__.__name__}. Message: {e}')
        except ccxt.BaseError as e:
            raise OperationalException(e)

    @retrier
    def get_fee(self, symbol='ETH/BTC', type='', side='', amount=1,
                price=1, taker_or_maker='maker') -> float:
        try:
            # validate that markets are loaded before trying to get fee
            if self._api.markets is None or len(self._api.markets) == 0:
                self._api.load_markets()

            return self._api.calculate_fee(symbol=symbol, type=type, side=side, amount=amount,
                                           price=price, takerOrMaker=taker_or_maker)['rate']
        except (ccxt.NetworkError, ccxt.ExchangeError) as e:
            raise TemporaryError(
                f'Could not get fee info due to {e.__class__.__name__}. Message: {e}')
        except ccxt.BaseError as e:
            raise OperationalException(e)

    def get_amount_lots(self, pair: str, amount: float) -> float:
        """
        get buyable amount rounding, ..
        """
        # validate that markets are loaded before trying to get fee
        if not self._api.markets:
            self._api.load_markets()
        return self._api.amount_to_lots(pair, amount)