"""
Shuffle pair list filter
"""
import logging
import random
from typing import Any, Dict, List

from freqtrade.constants import Config
from freqtrade.enums import RunMode
from freqtrade.exchange.types import Tickers
from freqtrade.plugins.pairlist.IPairList import IPairList


logger = logging.getLogger(__name__)


class ShuffleFilter(IPairList):

    def __init__(self, exchange, pairlistmanager,
                 config: Config, pairlistconfig: Dict[str, Any],
                 pairlist_pos: int) -> None:
        super().__init__(exchange, pairlistmanager, config, pairlistconfig, pairlist_pos)

        # Apply seed in backtesting mode to get comparable results,
        # but not in live modes to get a non-repeating order of pairs during live modes.
        if config.get('runmode') in (RunMode.LIVE, RunMode.DRY_RUN):
            self._seed = None
            logger.info("Live mode detected, not applying seed.")
        else:
            self._seed = pairlistconfig.get('seed')
            logger.info(f"Backtesting mode detected, applying seed value: {self._seed}")

        self._random = random.Random(self._seed)

    @property
    def needstickers(self) -> bool:
        """
        Boolean property defining if tickers are necessary.
        If no Pairlist requires tickers, an empty Dict is passed
        as tickers argument to filter_pairlist
        """
        return False

    def short_desc(self) -> str:
        """
        Short whitelist method description - used for startup-messages
        """
        return (f"{self.name} - Shuffling pairs" +
                (f", seed = {self._seed}." if self._seed is not None else "."))

    def filter_pairlist(self, pairlist: List[str], tickers: Tickers) -> List[str]:
        """
        Filters and sorts pairlist and returns the whitelist again.
        Called on each bot iteration - please use internal caching if necessary
        :param pairlist: pairlist to filter or sort
        :param tickers: Tickers (from exchange.get_tickers). May be cached.
        :return: new whitelist
        """
        # Shuffle is done inplace
        self._random.shuffle(pairlist)

        return pairlist