"""
Functions to convert data from one format to another
"""
import logging
from typing import Dict

import numpy as np
import pandas as pd
from pandas import DataFrame, to_datetime

from freqtrade.constants import DEFAULT_DATAFRAME_COLUMNS, Config
from freqtrade.enums import CandleType, TradingMode


logger = logging.getLogger(__name__)


def ohlcv_to_dataframe(ohlcv: list, timeframe: str, pair: str, *,
                       fill_missing: bool = True, drop_incomplete: bool = True) -> DataFrame:
    """
    Converts a list with candle (OHLCV) data (in format returned by ccxt.fetch_ohlcv)
    to a Dataframe
    :param ohlcv: list with candle (OHLCV) data, as returned by exchange.async_get_candle_history
    :param timeframe: timeframe (e.g. 5m). Used to fill up eventual missing data
    :param pair: Pair this data is for (used to warn if fillup was necessary)
    :param fill_missing: fill up missing candles with 0 candles
                         (see ohlcv_fill_up_missing_data for details)
    :param drop_incomplete: Drop the last candle of the dataframe, assuming it's incomplete
    :return: DataFrame
    """
    logger.debug(f"Converting candle (OHLCV) data to dataframe for pair {pair}.")
    cols = DEFAULT_DATAFRAME_COLUMNS
    df = DataFrame(ohlcv, columns=cols)

    df['date'] = to_datetime(df['date'], unit='ms', utc=True)

    # Some exchanges return int values for Volume and even for OHLC.
    # Convert them since TA-LIB indicators used in the strategy assume floats
    # and fail with exception...
    df = df.astype(dtype={'open': 'float', 'high': 'float', 'low': 'float', 'close': 'float',
                          'volume': 'float'})
    return clean_ohlcv_dataframe(df, timeframe, pair,
                                 fill_missing=fill_missing,
                                 drop_incomplete=drop_incomplete)


def clean_ohlcv_dataframe(data: DataFrame, timeframe: str, pair: str, *,
                          fill_missing: bool, drop_incomplete: bool) -> DataFrame:
    """
    Cleanse a OHLCV dataframe by
      * Grouping it by date (removes duplicate tics)
      * dropping last candles if requested
      * Filling up missing data (if requested)
    :param data: DataFrame containing candle (OHLCV) data.
    :param timeframe: timeframe (e.g. 5m). Used to fill up eventual missing data
    :param pair: Pair this data is for (used to warn if fillup was necessary)
    :param fill_missing: fill up missing candles with 0 candles
                         (see ohlcv_fill_up_missing_data for details)
    :param drop_incomplete: Drop the last candle of the dataframe, assuming it's incomplete
    :return: DataFrame
    """
    # group by index and aggregate results to eliminate duplicate ticks
    data = data.groupby(by='date', as_index=False, sort=True).agg({
        'open': 'first',
        'high': 'max',
        'low': 'min',
        'close': 'last',
        'volume': 'max',
    })
    # eliminate partial candle
    if drop_incomplete:
        data.drop(data.tail(1).index, inplace=True)
        logger.debug('Dropping last candle')

    if fill_missing:
        return ohlcv_fill_up_missing_data(data, timeframe, pair)
    else:
        return data


def ohlcv_fill_up_missing_data(dataframe: DataFrame, timeframe: str, pair: str) -> DataFrame:
    """
    Fills up missing data with 0 volume rows,
    using the previous close as price for "open", "high" "low" and "close", volume is set to 0

    """
    from freqtrade.exchange import timeframe_to_resample_freq

    ohlcv_dict = {
        'open': 'first',
        'high': 'max',
        'low': 'min',
        'close': 'last',
        'volume': 'sum'
    }
    resample_interval = timeframe_to_resample_freq(timeframe)
    # Resample to create "NAN" values
    df = dataframe.resample(resample_interval, on='date').agg(ohlcv_dict)

    # Forwardfill close for missing columns
    df['close'] = df['close'].ffill()
    # Use close for "open, high, low"
    df.loc[:, ['open', 'high', 'low']] = df[['open', 'high', 'low']].fillna(
        value={'open': df['close'],
               'high': df['close'],
               'low': df['close'],
               })
    df.reset_index(inplace=True)
    len_before = len(dataframe)
    len_after = len(df)
    pct_missing = (len_after - len_before) / len_before if len_before > 0 else 0
    if len_before != len_after:
        message = (f"Missing data fillup for {pair}, {timeframe}: "
                   f"before: {len_before} - after: {len_after} - {pct_missing:.2%}")
        if pct_missing > 0.01:
            logger.info(message)
        else:
            # Don't be verbose if only a small amount is missing
            logger.debug(message)
    return df


def trim_dataframe(df: DataFrame, timerange, *, df_date_col: str = 'date',
                   startup_candles: int = 0) -> DataFrame:
    """
    Trim dataframe based on given timerange
    :param df: Dataframe to trim
    :param timerange: timerange (use start and end date if available)
    :param df_date_col: Column in the dataframe to use as Date column
    :param startup_candles: When not 0, is used instead the timerange start date
    :return: trimmed dataframe
    """
    if startup_candles:
        # Trim candles instead of timeframe in case of given startup_candle count
        df = df.iloc[startup_candles:, :]
    else:
        if timerange.starttype == 'date':
            df = df.loc[df[df_date_col] >= timerange.startdt, :]
    if timerange.stoptype == 'date':
        df = df.loc[df[df_date_col] <= timerange.stopdt, :]
    return df


def trim_dataframes(preprocessed: Dict[str, DataFrame], timerange,
                    startup_candles: int) -> Dict[str, DataFrame]:
    """
    Trim startup period from analyzed dataframes
    :param preprocessed: Dict of pair: dataframe
    :param timerange: timerange (use start and end date if available)
    :param startup_candles: Startup-candles that should be removed
    :return: Dict of trimmed dataframes
    """
    processed: Dict[str, DataFrame] = {}

    for pair, df in preprocessed.items():
        trimed_df = trim_dataframe(df, timerange, startup_candles=startup_candles)
        if not trimed_df.empty:
            processed[pair] = trimed_df
        else:
            logger.warning(f'{pair} has no data left after adjusting for startup candles, '
                           f'skipping.')
    return processed


def order_book_to_dataframe(bids: list, asks: list) -> DataFrame:
    """
    TODO: This should get a dedicated test
    Gets order book list, returns dataframe with below format per suggested by creslin
    -------------------------------------------------------------------
     b_sum       b_size       bids       asks       a_size       a_sum
    -------------------------------------------------------------------
    """
    cols = ['bids', 'b_size']

    bids_frame = DataFrame(bids, columns=cols)
    # add cumulative sum column
    bids_frame['b_sum'] = bids_frame['b_size'].cumsum()
    cols2 = ['asks', 'a_size']
    asks_frame = DataFrame(asks, columns=cols2)
    # add cumulative sum column
    asks_frame['a_sum'] = asks_frame['a_size'].cumsum()

    frame = pd.concat([bids_frame['b_sum'], bids_frame['b_size'], bids_frame['bids'],
                       asks_frame['asks'], asks_frame['a_size'], asks_frame['a_sum']], axis=1,
                      keys=['b_sum', 'b_size', 'bids', 'asks', 'a_size', 'a_sum'])
    # logger.info('order book %s', frame )
    return frame


def convert_ohlcv_format(
    config: Config,
    convert_from: str,
    convert_to: str,
    erase: bool,
):
    """
    Convert OHLCV from one format to another
    :param config: Config dictionary
    :param convert_from: Source format
    :param convert_to: Target format
    :param erase: Erase source data (does not apply if source and target format are identical)
    """
    from freqtrade.data.history import get_datahandler
    src = get_datahandler(config['datadir'], convert_from)
    trg = get_datahandler(config['datadir'], convert_to)
    timeframes = config.get('timeframes', [config.get('timeframe')])
    logger.info(f"Converting candle (OHLCV) for timeframe {timeframes}")

    candle_types = [CandleType.from_string(ct) for ct in config.get('candle_types', [
        c.value for c in CandleType])]
    logger.info(candle_types)
    paircombs = src.ohlcv_get_available_data(config['datadir'], TradingMode.SPOT)
    paircombs.extend(src.ohlcv_get_available_data(config['datadir'], TradingMode.FUTURES))

    if 'pairs' in config:
        # Filter pairs
        paircombs = [comb for comb in paircombs if comb[0] in config['pairs']]

    if 'timeframes' in config:
        paircombs = [comb for comb in paircombs if comb[1] in config['timeframes']]
    paircombs = [comb for comb in paircombs if comb[2] in candle_types]

    paircombs = sorted(paircombs, key=lambda x: (x[0], x[1], x[2].value))

    formatted_paircombs = '\n'.join([f"{pair}, {timeframe}, {candle_type}"
                                    for pair, timeframe, candle_type in paircombs])

    logger.info(f"Converting candle (OHLCV) data for the following pair combinations:\n"
                f"{formatted_paircombs}")
    for pair, timeframe, candle_type in paircombs:
        data = src.ohlcv_load(pair=pair, timeframe=timeframe,
                              timerange=None,
                              fill_missing=False,
                              drop_incomplete=False,
                              startup_candles=0,
                              candle_type=candle_type)
        logger.info(f"Converting {len(data)} {timeframe} {candle_type} candles for {pair}")
        if len(data) > 0:
            trg.ohlcv_store(
                pair=pair,
                timeframe=timeframe,
                data=data,
                candle_type=candle_type
            )
            if erase and convert_from != convert_to:
                logger.info(f"Deleting source data for {pair} / {timeframe}")
                src.ohlcv_purge(pair=pair, timeframe=timeframe, candle_type=candle_type)


def reduce_dataframe_footprint(df: DataFrame) -> DataFrame:
    """
    Ensure all values are float32 in the incoming dataframe.
    :param df: Dataframe to be converted to float/int 32s
    :return: Dataframe converted to float/int 32s
    """

    logger.debug(f"Memory usage of dataframe is "
                 f"{df.memory_usage().sum() / 1024**2:.2f} MB")

    df_dtypes = df.dtypes
    for column, dtype in df_dtypes.items():
        if column in ['open', 'high', 'low', 'close', 'volume']:
            continue
        if dtype == np.float64:
            df_dtypes[column] = np.float32
        elif dtype == np.int64:
            df_dtypes[column] = np.int32
    df = df.astype(df_dtypes)

    logger.debug(f"Memory usage after optimization is: "
                 f"{df.memory_usage().sum() / 1024**2:.2f} MB")

    return df