Sith/eboutic/models.py

# -*- coding:utf-8 -*
#
# Copyright 2016,2017
# - Skia <skia@libskia.so>
#
# Ce fichier fait partie du site de l'Association des Étudiants de l'UTBM,
# http://ae.utbm.fr.
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License a published by the Free Software
# Foundation; either version 3 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 Sofware Foundation, Inc., 59 Temple
# Place - Suite 330, Boston, MA 02111-1307, USA.
#
#
import typing
from typing import List

from django.conf import settings
from django.db import models, DataError
from django.db.models import Sum, F
from django.utils.functional import cached_property
from django.utils.translation import gettext_lazy as _

from accounting.models import CurrencyField
from core.models import Group, User
from counter.models import Counter, Product, Selling, Refilling


def get_eboutic_products(user: User) -> List[Product]:
    products = (
        Counter.objects.get(type="EBOUTIC")
        .products.filter(product_type__isnull=False)
        .filter(archived=False)
        .filter(limit_age__lte=user.age)
        .annotate(category=F("product_type__name"))
    )
    return [p for p in products if p.can_be_sold_to(user)]


class Basket(models.Model):
    """
    Basket is built when the user connects to an eboutic page
    """

    user = models.ForeignKey(
        User,
        related_name="baskets",
        verbose_name=_("user"),
        blank=False,
        on_delete=models.CASCADE,
    )
    date = models.DateTimeField(_("date"), auto_now=True)

    def add_product(self, p: Product, q: int = 1):
        """
        Given p an object of the Product model and q an integer,
        add q items corresponding to this Product from the basket.

        If this function is called with a product not in the basket, no error will be raised
        """
        item = self.items.filter(product_id=p.id).first()
        if item is None:
            BasketItem(
                basket=self,
                product_id=p.id,
                product_name=p.name,
                type_id=p.product_type.id,
                quantity=q,
                product_unit_price=p.selling_price,
            ).save()
        else:
            item.quantity += q
            item.save()

    def del_product(self, p: Product, q: int = 1):
        """
        Given p an object of the Product model and q an integer,
        remove q items corresponding to this Product from the basket.

        If this function is called with a product not in the basket, no error will be raised
        """
        try:
            item = self.items.get(product_id=p.id)
        except BasketItem.DoesNotExist:
            return
        item.quantity -= q
        item.save()
        if item.quantity <= 0:
            item.delete()

    def clear(self) -> None:
        """
        Remove all items from this basket without deleting the basket
        """
        BasketItem.objects.filter(basket=self).delete()

    @cached_property
    def contains_refilling_item(self) -> bool:
        return self.items.filter(
            type_id=settings.SITH_COUNTER_PRODUCTTYPE_REFILLING
        ).exists()

    def get_total(self) -> float:
        total = self.items.aggregate(
            total=Sum(F("quantity") * F("product_unit_price"))
        )["total"]
        return float(total) if total is not None else 0

    @classmethod
    def from_session(cls, session) -> typing.Union["Basket", None]:
        """
        Given an HttpRequest django object, return the basket used in the current session
        if it exists else create a new one and return it
        """
        if "basket_id" in session:
            try:
                return cls.objects.get(id=session["basket_id"])
            except cls.DoesNotExist:
                return None
        return None

    def __str__(self):
        return "%s's basket (%d items)" % (self.user, self.items.all().count())


class Invoice(models.Model):
    """
    Invoices are generated once the payment has been validated
    """

    user = models.ForeignKey(
        User,
        related_name="invoices",
        verbose_name=_("user"),
        blank=False,
        on_delete=models.CASCADE,
    )
    date = models.DateTimeField(_("date"), auto_now=True)
    validated = models.BooleanField(_("validated"), default=False)

    def get_total(self) -> float:
        total = self.items.aggregate(
            total=Sum(F("quantity") * F("product_unit_price"))
        )["total"]
        return float(total) if total is not None else 0

    def validate(self, *args, **kwargs):
        if self.validated:
            raise DataError(_("Invoice already validated"))
        from counter.models import Customer

        if not Customer.objects.filter(user=self.user).exists():
            number = Customer.objects.count() + 1
            Customer(
                user=self.user,
                account_id=Customer.generate_account_id(number),
                amount=0,
            ).save()
        eboutic = Counter.objects.filter(type="EBOUTIC").first()
        for i in self.items.all():
            if i.type_id == settings.SITH_COUNTER_PRODUCTTYPE_REFILLING:
                new = Refilling(
                    counter=eboutic,
                    customer=self.user.customer,
                    operator=self.user,
                    amount=i.product_unit_price * i.quantity,
                    payment_method="CARD",
                    bank="OTHER",
                    date=self.date,
                )
                new.save()
            else:
                product = Product.objects.filter(id=i.product_id).first()
                new = Selling(
                    label=i.product_name,
                    counter=eboutic,
                    club=product.club,
                    product=product,
                    seller=self.user,
                    customer=self.user.customer,
                    unit_price=i.product_unit_price,
                    quantity=i.quantity,
                    payment_method="CARD",
                    is_validated=True,
                    date=self.date,
                )
                new.save()
        self.validated = True
        self.save()

    def __str__(self):
        return "%s - %s - %s" % (self.user, self.get_total(), self.date)


class AbstractBaseItem(models.Model):
    product_id = models.IntegerField(_("product id"))
    product_name = models.CharField(_("product name"), max_length=255)
    type_id = models.IntegerField(_("product type id"))
    product_unit_price = CurrencyField(_("unit price"))
    quantity = models.PositiveIntegerField(_("quantity"))

    class Meta:
        abstract = True

    def __str__(self):
        return "Item: %s (%s) x%d" % (
            self.product_name,
            self.product_unit_price,
            self.quantity,
        )


class BasketItem(AbstractBaseItem):
    basket = models.ForeignKey(
        Basket, related_name="items", verbose_name=_("basket"), on_delete=models.CASCADE
    )


class InvoiceItem(AbstractBaseItem):
    invoice = models.ForeignKey(
        Invoice,
        related_name="items",
        verbose_name=_("invoice"),
        on_delete=models.CASCADE,
    )