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##
# This file is part of TALER
# (C) 2014, 2015, 2016 INRIA
#
# TALER is free software; you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation; either version 3, or
# (at your option) any later version. TALER 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 TALER; see the file COPYING. If not, see
# <http://www.gnu.org/licenses/>
#
# @author Marcello Stanisci
# @author Florian Dold
from __future__ import unicode_literals
from typing import Any, Tuple
from django.contrib.auth.models import User
from django.db import models
from django.conf import settings
from django.core.exceptions import \
ValidationError, \
ObjectDoesNotExist
from .amount import Amount, BadFormatAmount, NumberTooBig
class InvalidAmount(Amount):
def __init__(self, currency):
super(InvalidAmount, self).__init__(currency, value=float('nan'), fraction=float('nan'))
def stringify(self, ndigits, pretty):
return "Invalid Amount, please report"
def dump(self):
return "Invalid Amount, please report"
##
# Helper function that instantiates a zero-valued @a Amount
# object.
def get_zero_amount() -> Amount:
return Amount(settings.TALER_CURRENCY)
##
# Custom implementation of the @a Amount class as a database type.
class AmountField(models.Field):
description = 'Amount object in Taler style'
##
# Return the database type of the serialized amount.
#
# @param self the object itself.
# @param connection the database connection.
# @return type of the serialized amount: varchar.
def db_type(self, connection: Any) -> str:
return "varchar"
##
# Stringifies the Amount object to feed the DB connector.
#
# @param self the object itself.
# @para value the @a Amount object to be serialized.
def get_prep_value(self, value: Amount) -> str:
if not value:
return "%s:0.0" % settings.TALER_CURRENCY
if settings.TALER_CURRENCY != value.currency:
raise CurrencyMismatch(settings.TALER_CURRENCY,
value.currency)
return value.stringify(settings.TALER_DIGITS)
##
# Parse the stringified Amount back to Python.
#
# @param value serialized amount coming from the database.
# (It is just a string in the usual CURRENCY:X.Y form)
# @param args currently unused.
# @return the @a Amount object.
@staticmethod
def from_db_value(value: str, *args) -> Amount:
del args # pacify PEP checkers
if value is None:
return Amount.parse(settings.TALER_CURRENCY)
try:
return Amount.parse(value)
except NumberTooBig:
# Keep the currency right to avoid causing
# exceptions if some operation is attempted
# against this invalid amount. NOTE that the
# value is defined as NaN, so no actual/useful
# amount will ever be generated using this one.
# And more, the NaN value will make it easier
# to scan the database to find these faulty
# amounts.
# We also decide to not raise exception here
# because they would propagate in too many places
# in the code, and it would be too verbose to
# just try-cactch any possible exception situation.
return InvalidAmount(settings.TALER_CURRENCY)
##
# Parse the stringified Amount back to Python. FIXME:
# why this serializer consider _more_ cases respect to the
# one above ('from_db_value')?
#
# @param value serialized amount coming from the database.
# (It is just a string in the usual CURRENCY:X.Y form)
# @param args currently unused.
# @return the @a Amount object.
def to_python(self, value: Any) -> Amount:
if isinstance(value, Amount):
return value
try:
if value is None:
return Amount.parse(settings.TALER_CURRENCY)
return Amount.parse(value)
except BadFormatAmount:
raise ValidationError(
"Invalid input for an amount string: %s" % value)
##
# Exception class to raise when a non-existent bank account is
# tried to be referenced.
class BankAccountDoesNotExist(ObjectDoesNotExist):
hint = "Specified bank account does not exist"
http_status_code = 404
##
# Exception class to raise when a non-existent bank transaction is
# tried to be referenced.
class BankTransactionDoesNotExist(ObjectDoesNotExist):
hint = "Specified bank transaction does not exist"
http_status_code = 404
##
# The class representing a bank account.
class BankAccount(models.Model):
is_public = models.BooleanField(default=False)
debit = models.BooleanField(default=False)
account_no = models.AutoField(primary_key=True)
user = models.OneToOneField(User, on_delete=models.CASCADE)
amount = AmountField(default=get_zero_amount)
DoesNotExist = BankAccountDoesNotExist
##
# The class representing a bank transaction.
class BankTransaction(models.Model):
amount = AmountField(default=False)
debit_account = models.ForeignKey(
BankAccount,
on_delete=models.CASCADE,
db_index=True,
related_name="debit_account")
credit_account = models.ForeignKey(
BankAccount,
on_delete=models.CASCADE,
db_index=True,
related_name="credit_account")
subject = models.CharField(
default="(no subject given)", max_length=200)
date = models.DateTimeField(
auto_now=True, db_index=True)
cancelled = models.BooleanField(default=False)
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