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k4ever/k4ever/buyable/models.py

162 lines
5.2 KiB

# -*- coding: utf-8 -*-
# This file is part of k4ever, a point-of-sale system
# Contact............ <k4ever@lists.someserver.de>
# Website............ http://k4ever.someserver.de/
# Bug tracker........ http://k4ever.someserver.de/report
#
# Licensed under GNU Affero General Public License v3 or later
from django.db import models
from django.contrib.auth.models import User
import datetime
from decimal import Decimal
from django.db.models.signals import pre_delete, post_delete
# Create your models here.
class BuyableType(models.Model):
""" Type/Category for a buyable object """
name = models.CharField(max_length=100)
def __unicode__(self):
return self.name
def itemcount(self):
return self.buyable_set.values().count()
class Buyable(models.Model):
""" Represents a buyable item. """
name = models.CharField(max_length=100)
price = models.DecimalField(max_digits=8, decimal_places=2)
image = models.ImageField(upload_to='img/buyable/', help_text="<strong>The Image needs to have a 1:1 aspect ratio.</strong>")
deposit = models.DecimalField(max_digits=8, decimal_places=2)
description = models.TextField()
buyableType = models.ManyToManyField(BuyableType)
barcode = models.CharField(max_length=100, default='', blank=True)
def hasDeposit(self):
""" Returns True if the item has deposit. """
return self.deposit > Decimal(0)
def __unicode__(self):
item = "%s (%.2f EUR" % (self.name, self.price)
if self.hasDeposit():
item += "/%.2f Pfand" % self.deposit
item += ")"
return item
def types(self):
typelist = ""
for item in self.buyableType.values_list():
typelist += item[1] + ", "
return typelist.rstrip(u", ")
class Order(models.Model):
""" Represents an order by the user, consists of several :class:`Purchases <Purchase>`. """
user = models.ForeignKey(User)
price = models.DecimalField(max_digits=8, decimal_places=2, default=Decimal(0))
dateTime = models.DateTimeField(auto_now_add=True)
def addItems(self, items):
for item in items:
self.purchase.add(item)
self.price += item.price
def updatePrice(self, instance, price, saveOrder=True):
""" Update price of order, save Order if saveOrder is True. """
self.price += price
if self.id and saveOrder:
self.save()
def __unicode__(self):
return "Price %s, User %s" % (self.price, self.user)
def itemList(self):
l = ""
for item in self.purchase_set.all():
l += item.buyable.name + u", "
return l.rstrip(u", ")
def save(self, *args, **kwargs):
profile = self.user.get_profile()
if self.id == None:
# new item, get it!
profile.balance -= self.price
profile.save()
else:
# get old
oldobj = Order.objects.get(id=self.id)
if oldobj.user == self.user:
profile = self.user.get_profile()
profile.balance -= (self.price - oldobj.price)
profile.save()
else:
oldProfile = oldobj.user.get_profile()
newProfile = self.user.get_profile()
oldProfile.balance += oldobj.price
oldProfile.save()
newprofile.balance -= self.price
self.save()
super(Order, self).save(*args, **kwargs)
@staticmethod
def pre_delete_signal(sender, instance, **kwargs):
# Normally we would not need this function as for consistency
# reasons and the behaviour of Buyables delete at deletion
# the orders price should be 0. But for the sake of not getting
# inconsistent with the users balance in the strangest situations
# we will check that here. This means (at least) one extra query
# per order deletion, as we don't get the updated object but the one
# where all the buyables have not updated the price
updOrder = Order.objects.get(id=instance.id)
if updOrder.price != Decimal("0"):
profile = updOrder.user.get_profile()
profile.balance += updOrder.price
profile.save()
pre_delete.connect(Order.pre_delete_signal, sender=Order)
class Purchase(models.Model):
""" Represents a :class:`Buyable` in a :class:`Order`.
Could be viewed as 'one bought item' or 'one item on the voucher'."""
order = models.ForeignKey(Order)
price = models.DecimalField(max_digits=8, decimal_places=2, default=None)
isDeposit = models.BooleanField()
buyable = models.ForeignKey(Buyable)
def updatePrice(self):
if self.isDeposit:
self.price = self.buyable.deposit
else:
self.price = self.buyable.price
def __unicode__(self):
return "%s%s" % (self.buyable.name, (self.isDeposit and " (deposit)" or ""))
def save(self, saveOrder=True, *args, **kwargs):
if self.price == None:
self.updatePrice()
if self.order:
if self.id == None:
self.order.updatePrice(self, self.price, saveOrder=saveOrder)
else:
# object exists, update.
oldobj = Purchase.objects.get(id=self.id)
if oldobj.order == self.order:
self.order.updatePrice(self, self.price - oldobj.price, saveOrder=saveOrder)
else:
oldobj.order.updatePrice(oldobj, -oldobj.price, saveOrder=saveOrder)
self.order.updatePrice(self, self.price, saveOrder=saveOrder)
super(Purchase, self).save(*args, **kwargs)
@staticmethod
def pre_delete_signal(sender, instance, **kwargs):
# FIXME: For many items this could get very inefficient
# Find workarround!
print "pre delete from purchase"
instance.order.updatePrice(instance, -instance.price, saveOrder=True)
pre_delete.connect(Purchase.pre_delete_signal, sender=Purchase)