import datetime
import os
from abc import ABC, abstractmethod
from decimal import Decimal

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

from xexe.exchange_rates import ExchangeRate


class RateFetcher(ABC):

    is_production_grade = False

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


class MockRateFetcher(RateFetcher):

    is_production_grade = False

    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, to_currency),
            rate_date=rate_date,
        )


class XERateFetcher(RateFetcher):

    is_production_grade = True

    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.
        )

        from_currency = Currency(response["from"])
        to_currency = Currency(response["to"][0]["quotecurrency"])
        rate_date = datetime.datetime.fromisoformat(
            response["timestamp"].replace(
                "Z", "+00:00"
            )  # Funny replace is necessary because of API response format
        ).date()
        rate = f"""{response["to"][0]["mid"]:.{CurrencyHelper.decimal_precision_for_currency(to_currency)}f}"""

        return ExchangeRate(
            from_currency=from_currency,
            to_currency=to_currency,
            rate_date=rate_date,
            rate=rate,
        )