public static Money Of(this Money money, Currency currency)
{
switch (money)
{
case SpecificMoney specific when specific.Currency == currency:
return(specific);
case BankCard _: return(money);
default: return(Amount.Zero(currency));
}
}
public static (Amount paid, Money remaining) Withdraw(
this Money money, Amount expense)
{
switch (money)
{
case Amount amt when amt.Value > expense.Value:
return(expense, amt.Subtract(expense));
case Amount amt when amt.Value > 0:
return(amt, Amount.Zero(amt.Currency));
case BankCard _: return(expense, money);
default: return(Amount.Zero(expense.Currency), money);
}
}
public static (Amount paid, Money remaining) Pay(this Money money, Amount expense)
{
Timestamp now = Timestamp.Now;
switch (money)
{
case Amount amt when amt.Currency != expense.Currency:
return(Amount.Zero(expense.Currency), money);
case Amount amt when amt.Value <= expense.Value:
return(amt, Amount.Zero(amt.Currency));
case GiftCard gift when gift.Currency != expense.Currency:
return(Amount.Zero(expense.Currency), gift);
case GiftCard gift when gift.ValidBefore.CompareTo(now) < 0:
return(Amount.Zero(expense.Currency), Amount.Zero(gift.Currency));
case GiftCard gift when gift.Value <= expense.Value:
return(new Amount(gift.Currency, gift.Value), Amount.Zero(gift.Currency));
case Empty _:
return(Amount.Zero(expense.Currency), money);
case Amount amt:
return(expense, amt.Subtract(expense));
case BankCard card when card.ValidBefore.CompareTo(now) < 0:
return(Amount.Zero(expense.Currency), Amount.Zero(expense.Currency));
case BankCard _:
return(expense, money);
default:
throw new ArgumentException(
$"Unsupported money type {money.GetType().Name}.");
}
}