from core.classes.http import HTTP
from core.models.local import Currency

import json

from logging import getLogger
from decimal import Decimal

logger = getLogger(__name__)

def update_currencies(currencies=[]):
    data = HTTP("https://api.ratesapi.io/api/latest").data
    loaded = json.loads(data)
    base = Currency.get_base().code

    if (not base == loaded["base"]) and (not base in loaded["rates"].keys()):
        raise ValueError(f"Base currency {base} not supported.")

    rates = {loaded["base"]: Decimal(1 if base == loaded["base"] else loaded["rates"][base])}

    for currency, rate in loaded["rates"].items():
        rates[currency] = Decimal(1) if base == currency else rates[loaded["base"]] / Decimal(rate)

    for currency in Currency.objects.all():
        if (not currencies) or (currency.code in currencies):
            if currency.code in rates.keys():
                currency.rate = rates[currency.code]
                currency.save()
                logger.info(f"Updated exchange rate for {currency.code}")
            else:
                logger.warn(f"Unable to set exchange rate for {currency.code} - currency not supported.")