"""
Various tool function for Freqtrade and scripts
"""
import gzip
import logging
import re
from datetime import datetime
from pathlib import Path
from typing import Any
from typing.io import IO

import rapidjson

from freqtrade.constants import DECIMAL_PER_COIN_FALLBACK, DECIMALS_PER_COIN


logger = logging.getLogger(__name__)


def decimals_per_coin(coin: str):
    """
    Helper method getting decimal amount for this coin
    example usage: f".{decimals_per_coin('USD')}f"
    :param coin: Which coin are we printing the price / value for
    """
    return DECIMALS_PER_COIN.get(coin, DECIMAL_PER_COIN_FALLBACK)


def round_coin_value(value: float, coin: str, show_coin_name=True) -> str:
    """
    Get price value for this coin
    :param value: Value to be printed
    :param coin: Which coin are we printing the price / value for
    :param show_coin_name: Return string in format: "222.22 USDT" or "222.22"
    :return: Formatted / rounded value (with or without coin name)
    """
    if show_coin_name:
        return f"{value:.{decimals_per_coin(coin)}f} {coin}"
    else:
        return f"{value:.{decimals_per_coin(coin)}f}"


def shorten_date(_date: str) -> str:
    """
    Trim the date so it fits on small screens
    """
    new_date = re.sub('seconds?', 'sec', _date)
    new_date = re.sub('minutes?', 'min', new_date)
    new_date = re.sub('hours?', 'h', new_date)
    new_date = re.sub('days?', 'd', new_date)
    new_date = re.sub('^an?', '1', new_date)
    return new_date


def file_dump_json(filename: Path, data: Any, is_zip: bool = False, log: bool = True) -> None:
    """
    Dump JSON data into a file
    :param filename: file to create
    :param data: JSON Data to save
    :return:
    """

    if is_zip:
        if filename.suffix != '.gz':
            filename = filename.with_suffix('.gz')
        if log:
            logger.info(f'dumping json to "{filename}"')

        with gzip.open(filename, 'w') as fpz:
            rapidjson.dump(data, fpz, default=str, number_mode=rapidjson.NM_NATIVE)
    else:
        if log:
            logger.info(f'dumping json to "{filename}"')
        with open(filename, 'w') as fp:
            rapidjson.dump(data, fp, default=str, number_mode=rapidjson.NM_NATIVE)

    logger.debug(f'done json to "{filename}"')


def json_load(datafile: IO) -> Any:
    """
    load data with rapidjson
    Use this to have a consistent experience,
    set number_mode to "NM_NATIVE" for greatest speed
    """
    return rapidjson.load(datafile, number_mode=rapidjson.NM_NATIVE)


def file_load_json(file):

    if file.suffix != ".gz":
        gzipfile = file.with_suffix(file.suffix + '.gz')
    else:
        gzipfile = file
    # Try gzip file first, otherwise regular json file.
    if gzipfile.is_file():
        logger.debug(f"Loading historical data from file {gzipfile}")
        with gzip.open(gzipfile) as datafile:
            pairdata = json_load(datafile)
    elif file.is_file():
        logger.debug(f"Loading historical data from file {file}")
        with open(file) as datafile:
            pairdata = json_load(datafile)
    else:
        return None
    return pairdata


def pair_to_filename(pair: str) -> str:
    for ch in ['/', '-', ' ', '.', '@', '$', '+', ':']:
        pair = pair.replace(ch, '_')
    return pair


def format_ms_time(date: int) -> str:
    """
    convert MS date to readable format.
    : epoch-string in ms
    """
    return datetime.fromtimestamp(date/1000.0).strftime('%Y-%m-%dT%H:%M:%S')


def deep_merge_dicts(source, destination):
    """
    Values from Source override destination, destination is returned (and modified!!)
    Sample:
    >>> a = { 'first' : { 'rows' : { 'pass' : 'dog', 'number' : '1' } } }
    >>> b = { 'first' : { 'rows' : { 'fail' : 'cat', 'number' : '5' } } }
    >>> merge(b, a) == { 'first' : { 'rows' : { 'pass' : 'dog', 'fail' : 'cat', 'number' : '5' } } }
    True
    """
    for key, value in source.items():
        if isinstance(value, dict):
            # get node or create one
            node = destination.setdefault(key, {})
            deep_merge_dicts(value, node)
        else:
            destination[key] = value

    return destination


def round_dict(d, n):
    """
    Rounds float values in the dict to n digits after the decimal point.
    """
    return {k: (round(v, n) if isinstance(v, float) else v) for k, v in d.items()}


def safe_value_fallback(obj: dict, key1: str, key2: str, default_value=None):
    """
    Search a value in obj, return this if it's not None.
    Then search key2 in obj - return that if it's not none - then use default_value.
    Else falls back to None.
    """
    if key1 in obj and obj[key1] is not None:
        return obj[key1]
    else:
        if key2 in obj and obj[key2] is not None:
            return obj[key2]
    return default_value


def safe_value_fallback2(dict1: dict, dict2: dict, key1: str, key2: str, default_value=None):
    """
    Search a value in dict1, return this if it's not None.
    Fall back to dict2 - return key2 from dict2 if it's not None.
    Else falls back to None.

    """
    if key1 in dict1 and dict1[key1] is not None:
        return dict1[key1]
    else:
        if key2 in dict2 and dict2[key2] is not None:
            return dict2[key2]
    return default_value


def plural(num: float, singular: str, plural: str = None) -> str:
    return singular if (num == 1 or num == -1) else plural or singular + 's'


def render_template(templatefile: str, arguments: dict = {}) -> str:

    from jinja2 import Environment, PackageLoader, select_autoescape

    env = Environment(
        loader=PackageLoader('freqtrade', 'templates'),
        autoescape=select_autoescape(['html', 'xml'])
    )
    template = env.get_template(templatefile)
    return template.render(**arguments)


def render_template_with_fallback(templatefile: str, templatefallbackfile: str,
                                  arguments: dict = {}) -> str:
    """
    Use templatefile if possible, otherwise fall back to templatefallbackfile
    """
    from jinja2.exceptions import TemplateNotFound
    try:
        return render_template(templatefile, arguments)
    except TemplateNotFound:
        return render_template(templatefallbackfile, arguments)