source: main/waeup.ikoba/branches/uli-payments/src/waeup/ikoba/payments/interfaces.py @ 12725

## $Id: interfaces.py 12725 2015-03-11 08:56:18Z uli $
##
## Copyright (C) 2011 Uli Fouquet & Henrik Bettermann
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
##
import decimal
from zc.sourcefactory.basic import BasicSourceFactory
from zope import schema
from zope.component import getUtilitiesFor
from zope.container.interfaces import IContainer
from zope.container.constraints import contains
from zope.interface import Interface, Attribute
from waeup.ikoba.interfaces import (
    IIkobaObject, SimpleIkobaVocabulary, ContextualDictSourceFactoryBase)
from waeup.ikoba.interfaces import MessageFactory as _
from waeup.ikoba.payments.currencies import ISO_4217_CURRENCIES_VOCAB

#: Possible states of payments
STATE_UNPAID = 1
STATE_PAID = 2
STATE_FAILED = 4

payment_states = SimpleIkobaVocabulary(
    (_('Not yet paid'), STATE_UNPAID),
    (_('Paid'), STATE_PAID),
    (_('Failed'), STATE_FAILED),
    )


class PaymentGatewayServicesSource(BasicSourceFactory):
    """A source that lists available payment services.

    Suitable for forms etc. Token and value correspond to the name the
    respective IPaymentGatewayService utility is registered with.
    """

    _services = None

    @classmethod
    def services(cls):
        """Cache the services registered on startup.

        We assume that services do not change after startup.
        """
        if cls._services is None:
            cls._services = dict(getUtilitiesFor(IPaymentGatewayService))
        return cls._services

    def getValues(self):
        """Get payment gateway registration names.
        """
        return sorted(PaymentGatewayServicesSource.services().keys())

    def getTitle(self, value):
        """Get title of the respective service, if it exists.
        """
        service = PaymentGatewayServicesSource.services().get(value, None)
        if service is not None:
            return service.title


class IPaymentGatewayService(Interface):
    """A financial gateway service.

    Any gateway provider might provide several services. For instance
    payments by credit card, scratch card, bank transfer, etc. An
    `IPaymentGatewayService` represents one of those services.

    Payment services are normally registered as a named global
    utility.
    """
    title = schema.TextLine(
        title=u'Title',
        description=u'Human readable name of gateway service.',
        required=True,
        )

    def create_payment(payer, payment_item_list, payee):
        """Create a payment.

        For all parameters we expect an object, that implements
        `IPayer`, `IPaymentItem`, or `IPayee` respectively. If not,
        then the given objects must be at least adaptable to the
        respective interface.

        Therfore you can pass in some `Customer` as long as there is
        some `IPayer` adapter for `Customer` objects defined.

        Returns an `IPayment` object.
        """

    def next_step(payment_id):
        """Returns a payment (as context) and a view name.

        May result in (None, None).
        """


class IPaymentGatewayServicesLister(Interface):
    """A utility that lists all valid payment gateways.

    This is a subset of the available payment methods, as some might
    be disabled in some site.

    Register your own lister in customized sites!
    """


class PaymentCategorySource(ContextualDictSourceFactoryBase):
    """A payment category source delivers all categories of payments.

    """
    #: name of dict to deliver from ikoba utils.
    DICT_NAME = 'PAYMENT_CATEGORIES'


class IPaymentsContainer(IIkobaObject):
    """A container for all kind of payment objects.

    """


class ICreditCard(Interface):
    """A credit card.

    A credit card is connected to a Payer.
    """
    credit_card_id = schema.TextLine(
        title=u'Internal Credit Card ID',
        required=True,
        )


class IPayableFinder(Interface):
    """Finds payables.

    For each type of content you want to make payable, you should
    define an IPayableFinder that can lookup payables in the
    site.

    This enables access from payments (which store payable ids only)
    to arbitrary content objects (for which a payable finder is
    registered under some name).

    The other way round (getting an id and other relevant data from
    any content object) is ensured by IPayable adapters.
    """
    def get_payable_by_id(item_id):
        """Get an item by its Id, or none.
        """


class IPayable(Interface):
    """Something that can be payed.

    Designed to serve as adapter. IPayables turn arbitrary content
    objects into something with a standarized interfaces for use with
    payments.
    """
    payable_id = schema.TextLine(
        title=u'ID of a payable',
        description=(u'It should be possible to lookup the payable id '
                     u'by some registered IPayableFinder later on'),
        required=True,
        readonly=True,
        )

    title = schema.TextLine(
        title=u'Title',
        description=u'A short description of the payed item.',
        required=True,
        default=u'',
        readonly=True,
        )


class IPaymentItem(Interface):
    """Something to sell.
    """
    item_id = schema.TextLine(
        title=u'Payment Item ID',
        required=True,
        )

    title = schema.TextLine(
        title=u'Title',
        description=u'A short title of the good sold.',
        required=True,
        default=u'Unnamed'
        )

    amount = schema.Decimal(
        title=u'Amount',
        description=u'Total amount, includung any taxes, fees, etc.',
        required=True,
        default=decimal.Decimal('0.00'),
        )


class IPayment(IContainer, IIkobaObject):
    """A base representation of payments.

    In a payment, a payer payes someone (the payee) for something, the
    item to pay.

    We currently support only the case where one payer pays one payee
    for one item. The item might include taxes, handling,
    shipping, etc.

    As in RL any payment is actually performed by some financial
    service provider (like paypal, interswitch, etc.), each of which
    might provide several types of payments (credit card, scratch
    card, you name it).

    In Ikoba we call financial service providers 'gateway' and their
    types of services are handled as gateway types. Therefore PayPal
    handling a credit card payment is different from PayPal handling a
    regular PayPal account transaction.

    A payment can be approve()d, which means the act of paying was
    really performed. It can also fail for any reason, in which case
    we mark the payment 'failed'.
    """
    contains(IPaymentItem)

    payment_id = schema.TextLine(
        title=u'Payment Identifier',
        default=None,
        required=True,
        )

    payer_id = schema.TextLine(
        title=u'Payer',
        default=None,
        required=True,
        )

    payee_id = schema.TextLine(
        title=u'Payee',
        default=None,
        required=False,
        )

    payable_id = schema.TextLine(
        title=u'ID of item/good being paid',
        default=None,
        required=False,
        )

    gateway_service = schema.Choice(
        title=u'Payment Gateway',
        description=u'Payment gateway that handles this transaction.',
        source=PaymentGatewayServicesSource(),
        default=None,
        required=True,
        )

    state = schema.Choice(
        title=_(u'Payment State'),
        default=STATE_UNPAID,
        vocabulary=payment_states,
        required=True,
        )

    creation_date = schema.Datetime(
        title=_(u'Creation Datetime'),
        readonly=False,
        required=False,
        )

    payment_date = schema.Datetime(
        title=_(u'Payment Datetime'),
        required=False,
        readonly=False,
        )

    currency = schema.Choice(
        title=u'Currency',
        source=ISO_4217_CURRENCIES_VOCAB,
        required=True,
        default='USD',
        )

    amount = Attribute("Sum of amounts of items contained")

    def approve():
        """Approve a payment.

        The payment was approved and can now be considered payed. This
        kind of approvement means the final one (in case there are
        several instances to ask).
        """

    def mark_failed(reason=None):
        """Mark the payment as failed.

        A failed payment was canceled due to technical problems,
        insufficient funds, etc.
        """

    def add_payment_item(item):
        """Payments contain payment items.

        Add one
        """


class IPayer(Interface):
    """A payer.
    """
    payer_id = schema.TextLine(
        title=u'Payer ID',
        required=True,
        )

    first_name = schema.TextLine(
        title=u'First Name',
        required=True,
        )

    last_name = schema.TextLine(
        title=u'Last Name',
        required=True,
        )


class IPayee(Interface):
    """A person or institution being paid.
    """
    payee_id = schema.TextLine(
        title=u'Payee ID',
        required=True
        )