timetracker/games/convert_price.py

import requests

from games.models import ExchangeRate, Purchase

# fixme: save preferred currency in user model
currency_to = "CZK"
currency_to = currency_to.lower()


def save_converted_info(purchase, converted_price, converted_currency):
    purchase.converted_price = converted_price
    purchase.converted_currency = converted_currency
    purchase.save()


def update_converted_prices():
    purchases = Purchase.objects.filter(
        converted_price__isnull=True, converted_currency__isnull=True
    )

    for purchase in purchases:
        if purchase.price_currency.lower() == currency_to or purchase.price == 0:
            save_converted_info(
                purchase, purchase.price, purchase.price_currency.lower()
            )
            continue
        year = purchase.date_purchased.year
        currency_from = purchase.price_currency.lower()
        exchange_rate = ExchangeRate.objects.filter(
            currency_from=currency_from, currency_to=currency_to, year=year
        ).first()

        if not exchange_rate:
            try:
                response = requests.get(
                    f"https://cdn.jsdelivr.net/npm/@fawazahmed0/currency-api@{year}-01-01/v1/currencies/{currency_from}.json"
                )
                response.raise_for_status()
                data = response.json()
                rate = data[currency_from].get(currency_to)

                if rate:
                    exchange_rate = ExchangeRate.objects.create(
                        currency_from=currency_from,
                        currency_to=currency_to,
                        year=year,
                        rate=rate,
                    )
            except requests.RequestException as e:
                print(
                    f"Failed to fetch exchange rate for {currency_from}->{currency_to} in {year}: {e}"
                )
        if exchange_rate:
            save_converted_info(
                purchase, purchase.price * exchange_rate.rate, currency_to
            )