class PaymentError(Exception):
    pass


class UserCancelled(PaymentError):
    """
    Exception for when a customer decides to cancel their payment
    after the process has started -- for example if they press a "Cancel"
    button on a third-party payment platform.
    """
    pass


class TransactionDeclined(PaymentError):
    pass


class GatewayError(PaymentError):
    pass


class InvalidGatewayRequestError(PaymentError):
    pass


class InsufficientPaymentSources(PaymentError):
    """
    Exception for when a user attempts to checkout without specifying enough
    payment sources to cover the entire order total.

    Eg. When selecting an allocation off a giftcard but not specifying a
    bankcard to take the remainder from.
    """
    pass


class RedirectRequired(PaymentError):
    """
    Exception to be used when payment processsing requires a redirect
    """

    def __init__(self, url):
        self.url = url


class UnableToTakePayment(PaymentError):
    """
    Exception to be used for ANTICIPATED payment errors (eg card number wrong,
    expiry date has passed).  The message passed here will be shown to the end
    user.
    """
    pass