public async Task <double> GetUserRemainingLimitAsync(int userId, string currencyCode, DateTime transactionDate)
{
double?currencyTransactionLimitPerMonth = await TransactionsRepository.GetCurrencyTransactionLimitAsync(currencyCode);
if (!currencyTransactionLimitPerMonth.HasValue)
{
throw new InvalidOperationException($"Currency transaction limite not found for currency code {currencyCode}");
}
double amountAlreadyExchanged = await TransactionsRepository.GetUserAmountExchangedPerMonthAsync(userId, currencyCode, transactionDate);
return(currencyTransactionLimitPerMonth.Value - amountAlreadyExchanged);
}