from .money_add import subtract_money
from .money_amount import Money
from .money_compare import min_money
from .retail_gift_card_balance_types import GiftCardRedemption


def redeem_gift_card(balance: Money, amount_due: Money) -> GiftCardRedemption:
    """Pay as much of ``amount_due`` as the card's balance allows."""
    if balance.minor < 0:
        raise ValueError("balance must not be negative, received %d" % balance.minor)
    if amount_due.minor < 0:
        raise ValueError(
            "amountDue must not be negative, received %d; a refund to a gift card is a top-up" % amount_due.minor
        )
    applied = min_money(balance, amount_due)
    still_due = subtract_money(amount_due, applied)
    return GiftCardRedemption(
        applied=applied,
        remaining_balance=subtract_money(balance, applied),
        still_due=still_due,
        fully_paid=still_due.minor == 0,
    )