symposion_app/registrasion/controllers/invoice.py

139 lines
4.5 KiB
Python

from decimal import Decimal
from django.core.exceptions import ObjectDoesNotExist
from django.db.models import Sum
from registrasion import models as rego
from cart import CartController
class InvoiceController(object):
def __init__(self, invoice):
self.invoice = invoice
self.update_validity() # Make sure this invoice is up-to-date
@classmethod
def for_cart(cls, cart):
''' Returns an invoice object for a given cart at its current revision.
If such an invoice does not exist, the cart is validated, and if valid,
an invoice is generated.'''
try:
invoice = rego.Invoice.objects.get(
cart=cart, cart_revision=cart.revision)
except ObjectDoesNotExist:
cart_controller = CartController(cart)
cart_controller.validate_cart() # Raises ValidationError on fail.
# Void past invoices for this cart
invoices = rego.Invoice.objects.filter(cart=cart).update(void=True)
invoice = cls._generate(cart)
return InvoiceController(invoice)
@classmethod
def resolve_discount_value(cls, item):
try:
condition = rego.DiscountForProduct.objects.get(
discount=item.discount,
product=item.product
)
except ObjectDoesNotExist:
condition = rego.DiscountForCategory.objects.get(
discount=item.discount,
category=item.product.category
)
if condition.percentage is not None:
value = item.product.price * (condition.percentage / 100)
else:
value = condition.price
return value
@classmethod
def _generate(cls, cart):
''' Generates an invoice for the given cart. '''
invoice = rego.Invoice.objects.create(
user=cart.user,
cart=cart,
cart_revision=cart.revision,
value=Decimal()
)
invoice.save()
# TODO: calculate line items.
product_items = rego.ProductItem.objects.filter(cart=cart)
product_items = product_items.order_by(
"product__category__order", "product__order"
)
discount_items = rego.DiscountItem.objects.filter(cart=cart)
invoice_value = Decimal()
for item in product_items:
product = item.product
line_item = rego.LineItem.objects.create(
invoice=invoice,
description="%s - %s" % (product.category.name, product.name),
quantity=item.quantity,
price=product.price,
)
line_item.save()
invoice_value += line_item.quantity * line_item.price
for item in discount_items:
line_item = rego.LineItem.objects.create(
invoice=invoice,
description=item.discount.description,
quantity=item.quantity,
price=cls.resolve_discount_value(item) * -1,
)
line_item.save()
invoice_value += line_item.quantity * line_item.price
# TODO: calculate line items from discounts
invoice.value = invoice_value
invoice.save()
return invoice
def update_validity(self):
''' Updates the validity of this invoice if the cart it is attached to
has updated. '''
if self.invoice.cart is not None:
if self.invoice.cart.revision != self.invoice.cart_revision:
self.void()
def void(self):
''' Voids the invoice. '''
self.invoice.void = True
self.invoice.save()
def pay(self, reference, amount):
''' Pays the invoice by the given amount. If the payment
equals the total on the invoice, finalise the invoice.
(NB should be transactional.)
'''
if self.invoice.cart is not None:
cart = CartController(self.invoice.cart)
cart.validate_cart() # Raises ValidationError if invalid
''' Adds a payment '''
payment = rego.Payment.objects.create(
invoice=self.invoice,
reference=reference,
amount=amount,
)
payment.save()
payments = rego.Payment.objects.filter(invoice=self.invoice)
agg = payments.aggregate(Sum("amount"))
total = agg["amount__sum"]
if total == self.invoice.value:
self.invoice.paid = True
cart = self.invoice.cart
cart.active = False
cart.save()
self.invoice.save()