import datetime
import os
from abc import ABC, abstractmethod

from money.currency import Currency
from money.money import Money
from xecd_rates_client import XecdClient


class ExchangeRate:

    def __init__(
        self,
        from_currency: Currency,
        to_currency: Currency,
        rate: Money,
        rate_date: datetime.date = None,
    ) -> None:
        self.from_currency
        self.to_currency
        self.rate
        self.rate_date


class RateFetcher(ABC):
    @abstractmethod
    def fetch_rate(
        self, from_currency: Currency, to_currency: Currency, rate_date: datetime.date
    ) -> ExchangeRate:
        pass


class MockRateFetcher(RateFetcher):

    def __init__(self) -> None:
        super().__init__()

    def fetch_rate(
        self, from_currency: Currency, to_currency: Currency, rate_date: datetime.date
    ) -> ExchangeRate:

        return ExchangeRate(
            from_currency=from_currency,
            to_currency=to_currency,
            rate=Money("42.0", to_currency),
            rate_date=rate_date,
        )


class XERateFetcher(RateFetcher):

    def __init__(self) -> None:
        super().__init__()
        self.xe_client = XecdClient(
            account_id=os.environ["XE_ACCOUNT_ID"],
            api_key=os.environ["XE_API_KEY"],
        )

    def fetch_rate(
        self, from_currency: Currency, to_currency: Currency, rate_date: datetime.date
    ) -> ExchangeRate:
        response = self.xe_client.historic_rate(
            rate_date.strftime("%Y-%m-%d"),
            "12:00",
            from_currency.value,  # .value will access the ISO 4217 str code of the currency
            to_currency.value,
            1,
            # always 1, because the rate we want is how much of to_curr does
            # 1 unit of from_curr get us.
        )

        # handle response into proper object