Sith/counter/models.py

# -*- coding:utf-8 -*-
#
# Copyright 2023 © AE UTBM
# ae@utbm.fr / ae.info@utbm.fr
# All contributors are listed in the CONTRIBUTORS file.
#
# This file is part of the website of the UTBM Student Association (AE UTBM),
# https://ae.utbm.fr.
#
# You can find the whole source code at https://github.com/ae-utbm/sith3
#
# LICENSED UNDER THE GNU GENERAL PUBLIC LICENSE VERSION 3 (GPLv3)
# SEE : https://raw.githubusercontent.com/ae-utbm/sith3/master/LICENSE
# OR WITHIN THE LOCAL FILE "LICENSE"
#
# PREVIOUSLY LICENSED UNDER THE MIT LICENSE,
# SEE : https://raw.githubusercontent.com/ae-utbm/sith3/master/LICENSE.old
# OR WITHIN THE LOCAL FILE "LICENSE.old"
#
from __future__ import annotations

import base64
import os
import random
import string
from datetime import date, datetime, timedelta
from typing import Optional, Tuple

from dict2xml import dict2xml
from django.conf import settings
from django.core.validators import MinLengthValidator
from django.db import models
from django.db.models import Exists, F, OuterRef, QuerySet, Sum, Value
from django.db.models.functions import Concat, Length
from django.forms import ValidationError
from django.urls import reverse
from django.utils import timezone
from django.utils.functional import cached_property
from django.utils.translation import gettext_lazy as _
from django_countries.fields import CountryField

from accounting.models import CurrencyField
from club.models import Club
from core.models import Group, Notification, User
from core.utils import get_start_of_semester
from sith.settings import SITH_COUNTER_OFFICES, SITH_MAIN_CLUB
from subscription.models import Subscription


class Customer(models.Model):
    """
    This class extends a user to make a customer. It adds some basic customers' information, such as the account ID, and
    is used by other accounting classes as reference to the customer, rather than using User
    """

    user = models.OneToOneField(User, primary_key=True, on_delete=models.CASCADE)
    account_id = models.CharField(_("account id"), max_length=10, unique=True)
    amount = CurrencyField(_("amount"), default=0)
    recorded_products = models.IntegerField(_("recorded product"), default=0)

    class Meta:
        verbose_name = _("customer")
        verbose_name_plural = _("customers")
        ordering = ["account_id"]

    def __str__(self):
        return "%s - %s" % (self.user.username, self.account_id)

    @property
    def can_record(self):
        return self.recorded_products > -settings.SITH_ECOCUP_LIMIT

    def can_record_more(self, number):
        return self.recorded_products - number >= -settings.SITH_ECOCUP_LIMIT

    @property
    def can_buy(self) -> bool:
        """
        Check if whether this customer has the right to
        purchase any item.
        This must be not confused with the Product.can_be_sold_to(user)
        method as the present method returns an information
        about a customer whereas the other tells something
        about the relation between a User (not a Customer,
        don't mix them) and a Product.
        """
        subscription = self.user.subscriptions.order_by("subscription_end").last()
        if subscription is None:
            return False
        return (date.today() - subscription.subscription_end) < timedelta(days=90)

    @classmethod
    def get_or_create(cls, user: User) -> Tuple[Customer, bool]:
        """
        Work in pretty much the same way as the usual get_or_create method,
        but with the default field replaced by some under the hood.

        If the user has an account, return it as is.
        Else create a new account with no money on it and a new unique account id

        Example : ::

            user = User.objects.get(pk=1)
            account, created = Customer.get_or_create(user)
            if created:
                print(f"created a new account with id {account.id}")
            else:
                print(f"user has already an account, with {account.id} € on it"
        """
        if hasattr(user, "customer"):
            return user.customer, False

        # account_id are always a number with a letter appended
        account_id = (
            Customer.objects.order_by(Length("account_id"), "account_id")
            .values("account_id")
            .last()
        )
        if account_id is None:
            # legacy from the old site
            account = cls.objects.create(user=user, account_id="1504a")
            return account, True

        account_id = account_id["account_id"]
        account_num = int(account_id[:-1])
        while Customer.objects.filter(account_id=account_id).exists():
            # when entering the first iteration, we are using an already existing account id
            # so the loop should always execute at least one time
            account_num += 1
            account_id = f"{account_num}{random.choice(string.ascii_lowercase)}"

        account = cls.objects.create(user=user, account_id=account_id)
        return account, True

    def save(self, allow_negative=False, is_selling=False, *args, **kwargs):
        """
        is_selling : tell if the current action is a selling
        allow_negative : ignored if not a selling. Allow a selling to put the account in negative
        Those two parameters avoid blocking the save method of a customer if his account is negative
        """
        if self.amount < 0 and (is_selling and not allow_negative):
            raise ValidationError(_("Not enough money"))
        super(Customer, self).save(*args, **kwargs)

    def recompute_amount(self):
        refillings = self.refillings.aggregate(sum=Sum(F("amount")))["sum"]
        self.amount = refillings if refillings is not None else 0
        purchases = (
            self.buyings.filter(payment_method="SITH_ACCOUNT")
            .annotate(amount=F("quantity") * F("unit_price"))
            .aggregate(sum=Sum(F("amount")))
        )["sum"]
        if purchases is not None:
            self.amount -= purchases
        self.save()

    def get_absolute_url(self):
        return reverse("core:user_account", kwargs={"user_id": self.user.pk})

    def get_full_url(self):
        return "".join(["https://", settings.SITH_URL, self.get_absolute_url()])


class BillingInfo(models.Model):
    """
    Represent the billing information of a user, which are required
    by the 3D-Secure v2 system used by the etransaction module
    """

    customer = models.OneToOneField(
        Customer, related_name="billing_infos", on_delete=models.CASCADE
    )

    # declaring surname and name even though they are already defined
    # in User add some redundancy, but ensures that the billing infos
    # shall stay correct, whatever shenanigans the user commits on its profile
    first_name = models.CharField(_("First name"), max_length=22)
    last_name = models.CharField(_("Last name"), max_length=22)
    address_1 = models.CharField(_("Address 1"), max_length=50)
    address_2 = models.CharField(_("Address 2"), max_length=50, blank=True, null=True)
    zip_code = models.CharField(_("Zip code"), max_length=16)  # code postal
    city = models.CharField(_("City"), max_length=50)
    country = CountryField(blank_label=_("Country"))

    def to_3dsv2_xml(self) -> str:
        """
        Convert the data from this model into a xml usable
        by the online paying service of the Crédit Agricole bank.
        see : `https://www.ca-moncommerce.com/espace-client-mon-commerce/up2pay-e-transactions/ma-documentation/manuel-dintegration-focus-3ds-v2/principes-generaux/#integration-3dsv2-developpeur-webmaster`
        """
        data = {
            "Address": {
                "FirstName": self.first_name,
                "LastName": self.last_name,
                "Address1": self.address_1,
                "ZipCode": self.zip_code,
                "City": self.city,
                "CountryCode": self.country.numeric,  # ISO-3166-1 numeric code
            }
        }
        if self.address_2:
            data["Address"]["Address2"] = self.address_2
        xml = dict2xml(data, wrap="Billing", newlines=False)
        return '<?xml version="1.0" encoding="UTF-8" ?>' + xml

    def __str__(self):
        return f"{self.first_name} {self.last_name}"


class ProductType(models.Model):
    """
    This describes a product type
    Useful only for categorizing, changes are made at the product level for now
    """

    name = models.CharField(_("name"), max_length=30)
    description = models.TextField(_("description"), null=True, blank=True)
    comment = models.TextField(_("comment"), null=True, blank=True)
    icon = models.ImageField(upload_to="products", null=True, blank=True)

    # priority holds no real backend logic but helps to handle the order in which
    # the items are to be shown to the user
    priority = models.PositiveIntegerField(default=0)

    class Meta:
        verbose_name = _("product type")
        ordering = ["-priority", "name"]

    def is_owned_by(self, user):
        """
        Method to see if that object can be edited by the given user
        """
        if user.is_anonymous:
            return False
        if user.is_in_group(pk=settings.SITH_GROUP_ACCOUNTING_ADMIN_ID):
            return True
        return False

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse("counter:producttype_list")


class Product(models.Model):
    """
    This describes a product, with all its related informations
    """

    name = models.CharField(_("name"), max_length=64)
    description = models.TextField(_("description"), blank=True)
    product_type = models.ForeignKey(
        ProductType,
        related_name="products",
        verbose_name=_("product type"),
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
    )
    code = models.CharField(_("code"), max_length=16, blank=True)
    purchase_price = CurrencyField(_("purchase price"))
    selling_price = CurrencyField(_("selling price"))
    special_selling_price = CurrencyField(_("special selling price"))
    icon = models.ImageField(
        upload_to="products", null=True, blank=True, verbose_name=_("icon")
    )
    club = models.ForeignKey(
        Club, related_name="products", verbose_name=_("club"), on_delete=models.CASCADE
    )
    limit_age = models.IntegerField(_("limit age"), default=0)
    tray = models.BooleanField(_("tray price"), default=False)
    parent_product = models.ForeignKey(
        "self",
        related_name="children_products",
        verbose_name=_("parent product"),
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
    )
    buying_groups = models.ManyToManyField(
        Group, related_name="products", verbose_name=_("buying groups"), blank=True
    )
    archived = models.BooleanField(_("archived"), default=False)

    class Meta:
        verbose_name = _("product")

    @property
    def is_record_product(self):
        return settings.SITH_ECOCUP_CONS == self.id

    @property
    def is_unrecord_product(self):
        return settings.SITH_ECOCUP_DECO == self.id

    def is_owned_by(self, user):
        """
        Method to see if that object can be edited by the given user
        """
        if user.is_anonymous:
            return False
        if user.is_in_group(
            pk=settings.SITH_GROUP_ACCOUNTING_ADMIN_ID
        ) or user.is_in_group(pk=settings.SITH_GROUP_COUNTER_ADMIN_ID):
            return True
        return False

    def get_absolute_url(self):
        return reverse("counter:product_list")

    def can_be_sold_to(self, user: User) -> bool:
        """
        Check if whether the user given in parameter has the right to buy
        this product or not.

        This must be not confused with the Customer.can_buy()
        method as the present method returns an information
        about the relation between a User and a Product,
        whereas the other tells something about a Customer
        (and not a user, they are not the same model).

        :return: True if the user can buy this product else False
        """
        if not self.buying_groups.exists():
            return True
        for group_id in self.buying_groups.values_list("pk", flat=True):
            if user.is_in_group(pk=group_id):
                return True
        return False

    @property
    def profit(self):
        return self.selling_price - self.purchase_price

    def __str__(self):
        return "%s (%s)" % (self.name, self.code)


class CounterQuerySet(models.QuerySet):
    def annotate_has_barman(self, user: User) -> CounterQuerySet:
        """
        Annotate the queryset with the `user_is_barman` field.
        For each counter, this field has value True if the user
        is a barman of this counter, else False.

        :param user: the user we want to check if he is a barman

        Example::

            sli = User.objects.get(username="sli")
            counters = (
                Counter.objects
                .annotate_has_barman(sli)  # add the user_has_barman boolean field
                .filter(has_annotated_barman=True)  # keep only counters where this user is barman
            )
            print("Sli est barman dans les comptoirs suivants :")
            for counter in counters:
                print(f"- {counter.name}")
        """
        subquery = user.counters.filter(pk=OuterRef("pk"))
        # noinspection PyTypeChecker
        return self.annotate(has_annotated_barman=Exists(subquery))


class Counter(models.Model):
    name = models.CharField(_("name"), max_length=30)
    club = models.ForeignKey(
        Club, related_name="counters", verbose_name=_("club"), on_delete=models.CASCADE
    )
    products = models.ManyToManyField(
        Product, related_name="counters", verbose_name=_("products"), blank=True
    )
    type = models.CharField(
        _("counter type"),
        max_length=255,
        choices=[("BAR", _("Bar")), ("OFFICE", _("Office")), ("EBOUTIC", _("Eboutic"))],
    )
    sellers = models.ManyToManyField(
        User, verbose_name=_("sellers"), related_name="counters", blank=True
    )
    edit_groups = models.ManyToManyField(
        Group, related_name="editable_counters", blank=True
    )
    view_groups = models.ManyToManyField(
        Group, related_name="viewable_counters", blank=True
    )
    token = models.CharField(_("token"), max_length=30, null=True, blank=True)

    objects = CounterQuerySet.as_manager()

    class Meta:
        verbose_name = _("counter")

    def __getattribute__(self, name):
        if name == "edit_groups":
            return Group.objects.filter(
                name=self.club.unix_name + settings.SITH_BOARD_SUFFIX
            ).all()
        return object.__getattribute__(self, name)

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        if self.type == "EBOUTIC":
            return reverse("eboutic:main")
        return reverse("counter:details", kwargs={"counter_id": self.id})

    def is_owned_by(self, user):
        if user.is_anonymous:
            return False
        mem = self.club.get_membership_for(user)
        if mem and mem.role >= 7:
            return True
        return user.is_in_group(pk=settings.SITH_GROUP_COUNTER_ADMIN_ID)

    def can_be_viewed_by(self, user):
        if self.type == "BAR":
            return True
        return user.is_board_member or user in self.sellers.all()

    def gen_token(self):
        """Generate a new token for this counter"""
        self.token = "".join(
            random.choice(string.ascii_letters + string.digits) for x in range(30)
        )
        self.save()

    def add_barman(self, user):
        """
        Logs a barman in to the given counter
        A user is stored as a tuple with its login time
        """
        Permanency(user=user, counter=self, start=timezone.now(), end=None).save()

    def del_barman(self, user):
        """
        Logs a barman out and store its permanency
        """
        perm = Permanency.objects.filter(counter=self, user=user, end=None).all()
        for p in perm:
            p.end = p.activity
            p.save()

    @cached_property
    def barmen_list(self):
        return self.get_barmen_list()

    def get_barmen_list(self):
        """
        Returns the barman list as list of User

        Also handle the timeout of the barmen
        """
        pl = Permanency.objects.filter(counter=self, end=None).all()
        bl = []
        for p in pl:
            if timezone.now() - p.activity < timedelta(
                minutes=settings.SITH_BARMAN_TIMEOUT
            ):
                bl.append(p.user)
            else:
                p.end = p.activity
                p.save()
        return bl

    def get_random_barman(self):
        """
        Return a random user being currently a barman
        """
        bl = self.get_barmen_list()
        return bl[random.randrange(0, len(bl))]

    def update_activity(self):
        """
        Update the barman activity to prevent timeout
        """
        for p in Permanency.objects.filter(counter=self, end=None).all():
            p.save()  # Update activity

    def is_open(self):
        return len(self.barmen_list) > 0

    def is_inactive(self):
        """
        Returns True if the counter self is inactive from SITH_COUNTER_MINUTE_INACTIVE's value minutes, else False
        """
        return self.is_open() and (
            (timezone.now() - self.permanencies.order_by("-activity").first().activity)
            > timedelta(minutes=settings.SITH_COUNTER_MINUTE_INACTIVE)
        )

    def barman_list(self):
        """
        Returns the barman id list
        """
        return [b.id for b in self.get_barmen_list()]

    def can_refill(self):
        """
        Show if the counter authorize the refilling with physic money
        """

        if self.type != "BAR":
            return False
        if self.id in SITH_COUNTER_OFFICES:
            # If the counter is either 'AE' or 'BdF', refills are authorized
            return True
        is_ae_member = False
        ae = Club.objects.get(unix_name=SITH_MAIN_CLUB["unix_name"])
        for barman in self.get_barmen_list():
            if ae.get_membership_for(barman):
                is_ae_member = True
        return is_ae_member

    def get_top_barmen(self) -> QuerySet:
        """
        Return a QuerySet querying the office hours stats of all the barmen of all time
        of this counter, ordered by descending number of hours.

        Each element of the QuerySet corresponds to a barman and has the following data :
            - the full name (first name + last name) of the barman
            - the nickname of the barman
            - the promo of the barman
            - the total number of office hours the barman did attend
        """
        return (
            self.permanencies.exclude(end=None)
            .annotate(
                name=Concat(F("user__first_name"), Value(" "), F("user__last_name"))
            )
            .annotate(nickname=F("user__nick_name"))
            .annotate(promo=F("user__promo"))
            .values("user", "name", "nickname", "promo")
            .annotate(perm_sum=Sum(F("end") - F("start")))
            .exclude(perm_sum=None)
            .order_by("-perm_sum")
        )

    def get_top_customers(self, since: Optional[date] = None) -> QuerySet:
        """
        Return a QuerySet querying the money spent by customers of this counter
        since the specified date, ordered by descending amount of money spent.

        Each element of the QuerySet corresponds to a customer and has the following data :
            - the full name (first name + last name) of the customer
            - the nickname of the customer
            - the amount of money spent by the customer
        """
        if since is None:
            since = get_start_of_semester()
        return (
            self.sellings.filter(date__gte=since)
            .annotate(
                name=Concat(
                    F("customer__user__first_name"),
                    Value(" "),
                    F("customer__user__last_name"),
                )
            )
            .annotate(nickname=F("customer__user__nick_name"))
            .annotate(promo=F("customer__user__promo"))
            .annotate(user=F("customer__user"))
            .values("user", "promo", "name", "nickname")
            .annotate(
                selling_sum=Sum(
                    F("unit_price") * F("quantity"), output_field=CurrencyField()
                )
            )
            .filter(selling_sum__gt=0)
            .order_by("-selling_sum")
        )

    def get_total_sales(self, since=None) -> CurrencyField:
        """
        Compute and return the total turnover of this counter
        since the date specified in parameter (by default, since the start of the current
        semester)
        :param since: timestamp from which to perform the calculation
        :type since: datetime | date | None
        :return: Total revenue earned at this counter
        """
        if since is None:
            since = get_start_of_semester()
        if isinstance(since, date):
            since = datetime.combine(since, datetime.min.time())
        total = self.sellings.filter(date__gte=since).aggregate(
            total=Sum(F("quantity") * F("unit_price"), output_field=CurrencyField())
        )["total"]
        return total if total is not None else CurrencyField(0)


class Refilling(models.Model):
    """
    Handle the refilling
    """

    counter = models.ForeignKey(
        Counter, related_name="refillings", blank=False, on_delete=models.CASCADE
    )
    amount = CurrencyField(_("amount"))
    operator = models.ForeignKey(
        User,
        related_name="refillings_as_operator",
        blank=False,
        on_delete=models.CASCADE,
    )
    customer = models.ForeignKey(
        Customer, related_name="refillings", blank=False, on_delete=models.CASCADE
    )
    date = models.DateTimeField(_("date"))
    payment_method = models.CharField(
        _("payment method"),
        max_length=255,
        choices=settings.SITH_COUNTER_PAYMENT_METHOD,
        default="CASH",
    )
    bank = models.CharField(
        _("bank"), max_length=255, choices=settings.SITH_COUNTER_BANK, default="OTHER"
    )
    is_validated = models.BooleanField(_("is validated"), default=False)

    class Meta:
        verbose_name = _("refilling")

    def __str__(self):
        return "Refilling: %.2f for %s" % (
            self.amount,
            self.customer.user.get_display_name(),
        )

    def is_owned_by(self, user):
        if user.is_anonymous:
            return False
        return user.is_owner(self.counter) and self.payment_method != "CARD"

    def delete(self, *args, **kwargs):
        self.customer.amount -= self.amount
        self.customer.save()
        super(Refilling, self).delete(*args, **kwargs)

    def save(self, *args, **kwargs):
        if not self.date:
            self.date = timezone.now()
        self.full_clean()
        if not self.is_validated:
            self.customer.amount += self.amount
            self.customer.save()
            self.is_validated = True
        if self.customer.user.preferences.notify_on_refill:
            Notification(
                user=self.customer.user,
                url=reverse(
                    "core:user_account_detail",
                    kwargs={
                        "user_id": self.customer.user.id,
                        "year": self.date.year,
                        "month": self.date.month,
                    },
                ),
                param=str(self.amount),
                type="REFILLING",
            ).save()
        super(Refilling, self).save(*args, **kwargs)


class Selling(models.Model):
    """
    Handle the sellings
    """

    label = models.CharField(_("label"), max_length=64)
    product = models.ForeignKey(
        Product,
        related_name="sellings",
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
    )
    counter = models.ForeignKey(
        Counter,
        related_name="sellings",
        null=True,
        blank=False,
        on_delete=models.SET_NULL,
    )
    club = models.ForeignKey(
        Club, related_name="sellings", null=True, blank=False, on_delete=models.SET_NULL
    )
    unit_price = CurrencyField(_("unit price"))
    quantity = models.IntegerField(_("quantity"))
    seller = models.ForeignKey(
        User,
        related_name="sellings_as_operator",
        null=True,
        blank=False,
        on_delete=models.SET_NULL,
    )
    customer = models.ForeignKey(
        Customer,
        related_name="buyings",
        null=True,
        blank=False,
        on_delete=models.SET_NULL,
    )
    date = models.DateTimeField(_("date"))
    payment_method = models.CharField(
        _("payment method"),
        max_length=255,
        choices=[("SITH_ACCOUNT", _("Sith account")), ("CARD", _("Credit card"))],
        default="SITH_ACCOUNT",
    )
    is_validated = models.BooleanField(_("is validated"), default=False)

    class Meta:
        verbose_name = _("selling")

    def __str__(self):
        return "Selling: %d x %s (%f) for %s" % (
            self.quantity,
            self.label,
            self.quantity * self.unit_price,
            self.customer.user.get_display_name(),
        )

    def is_owned_by(self, user):
        if user.is_anonymous:
            return False
        return user.is_owner(self.counter) and self.payment_method != "CARD"

    def can_be_viewed_by(self, user):
        if (
            not hasattr(self, "customer") or self.customer is None
        ):  # Customer can be set to Null
            return False
        return user == self.customer.user

    def delete(self, *args, **kwargs):
        if self.payment_method == "SITH_ACCOUNT":
            self.customer.amount += self.quantity * self.unit_price
            self.customer.save()
        super(Selling, self).delete(*args, **kwargs)

    def send_mail_customer(self):
        event = self.product.eticket.event_title or _("Unknown event")
        subject = _("Eticket bought for the event %(event)s") % {"event": event}
        message_html = _(
            "You bought an eticket for the event %(event)s.\nYou can download it directly from this link %(eticket)s.\nYou can also retrieve all your e-tickets on your account page %(url)s."
        ) % {
            "event": event,
            "url": "".join(
                (
                    '<a href="',
                    self.customer.get_full_url(),
                    '">',
                    self.customer.get_full_url(),
                    "</a>",
                )
            ),
            "eticket": "".join(
                (
                    '<a href="',
                    self.get_eticket_full_url(),
                    '">',
                    self.get_eticket_full_url(),
                    "</a>",
                )
            ),
        }
        message_txt = _(
            "You bought an eticket for the event %(event)s.\nYou can download it directly from this link %(eticket)s.\nYou can also retrieve all your e-tickets on your account page %(url)s."
        ) % {
            "event": event,
            "url": self.customer.get_full_url(),
            "eticket": self.get_eticket_full_url(),
        }
        self.customer.user.email_user(subject, message_txt, html_message=message_html)

    def save(self, allow_negative=False, *args, **kwargs):
        """
        allow_negative : Allow this selling to use more money than available for this user
        """
        if not self.date:
            self.date = timezone.now()
        self.full_clean()
        if not self.is_validated:
            self.customer.amount -= self.quantity * self.unit_price
            self.customer.save(allow_negative=allow_negative, is_selling=True)
            self.is_validated = True
        u = User.objects.filter(id=self.customer.user.id).first()
        if u.was_subscribed:
            if (
                self.product
                and self.product.id == settings.SITH_PRODUCT_SUBSCRIPTION_ONE_SEMESTER
            ):
                sub = Subscription(
                    member=u,
                    subscription_type="un-semestre",
                    payment_method="EBOUTIC",
                    location="EBOUTIC",
                )
                sub.subscription_start = Subscription.compute_start()
                sub.subscription_start = Subscription.compute_start(
                    duration=settings.SITH_SUBSCRIPTIONS[sub.subscription_type][
                        "duration"
                    ]
                )
                sub.subscription_end = Subscription.compute_end(
                    duration=settings.SITH_SUBSCRIPTIONS[sub.subscription_type][
                        "duration"
                    ],
                    start=sub.subscription_start,
                )
                sub.save()
            elif (
                self.product
                and self.product.id == settings.SITH_PRODUCT_SUBSCRIPTION_TWO_SEMESTERS
            ):
                u = User.objects.filter(id=self.customer.user.id).first()
                sub = Subscription(
                    member=u,
                    subscription_type="deux-semestres",
                    payment_method="EBOUTIC",
                    location="EBOUTIC",
                )
                sub.subscription_start = Subscription.compute_start()
                sub.subscription_start = Subscription.compute_start(
                    duration=settings.SITH_SUBSCRIPTIONS[sub.subscription_type][
                        "duration"
                    ]
                )
                sub.subscription_end = Subscription.compute_end(
                    duration=settings.SITH_SUBSCRIPTIONS[sub.subscription_type][
                        "duration"
                    ],
                    start=sub.subscription_start,
                )
                sub.save()
        if self.customer.user.preferences.notify_on_click:
            Notification(
                user=self.customer.user,
                url=reverse(
                    "core:user_account_detail",
                    kwargs={
                        "user_id": self.customer.user.id,
                        "year": self.date.year,
                        "month": self.date.month,
                    },
                ),
                param="%d x %s" % (self.quantity, self.label),
                type="SELLING",
            ).save()
        super(Selling, self).save(*args, **kwargs)
        try:
            # The product has no id until it's saved
            if self.product.eticket:
                self.send_mail_customer()
        except:
            pass

    def get_eticket_full_url(self):
        eticket_url = reverse("counter:eticket_pdf", kwargs={"selling_id": self.id})
        return "".join(["https://", settings.SITH_URL, eticket_url])


class Permanency(models.Model):
    """
    This class aims at storing a traceability of who was barman where and when
    """

    user = models.ForeignKey(
        User,
        related_name="permanencies",
        verbose_name=_("user"),
        on_delete=models.CASCADE,
    )
    counter = models.ForeignKey(
        Counter,
        related_name="permanencies",
        verbose_name=_("counter"),
        on_delete=models.CASCADE,
    )
    start = models.DateTimeField(_("start date"))
    end = models.DateTimeField(_("end date"), null=True, db_index=True)
    activity = models.DateTimeField(_("last activity date"), auto_now=True)

    class Meta:
        verbose_name = _("permanency")

    def __str__(self):
        return "%s in %s from %s (last activity: %s) to %s" % (
            self.user,
            self.counter,
            self.start.strftime("%Y-%m-%d %H:%M:%S"),
            self.activity.strftime("%Y-%m-%d %H:%M:%S"),
            self.end.strftime("%Y-%m-%d %H:%M:%S") if self.end else "",
        )

    @property
    def duration(self):
        if self.end is None:
            return self.activity - self.start
        return self.end - self.start


class CashRegisterSummary(models.Model):
    user = models.ForeignKey(
        User,
        related_name="cash_summaries",
        verbose_name=_("user"),
        on_delete=models.CASCADE,
    )
    counter = models.ForeignKey(
        Counter,
        related_name="cash_summaries",
        verbose_name=_("counter"),
        on_delete=models.CASCADE,
    )
    date = models.DateTimeField(_("date"))
    comment = models.TextField(_("comment"), null=True, blank=True)
    emptied = models.BooleanField(_("emptied"), default=False)

    class Meta:
        verbose_name = _("cash register summary")

    def __str__(self):
        return "At %s by %s - Total: %s €" % (self.counter, self.user, self.get_total())

    def __getattribute__(self, name):
        if name[:5] == "check":
            checks = self.items.filter(check=True).order_by("value").all()
        if name == "ten_cents":
            return self.items.filter(value=0.1, check=False).first()
        elif name == "twenty_cents":
            return self.items.filter(value=0.2, check=False).first()
        elif name == "fifty_cents":
            return self.items.filter(value=0.5, check=False).first()
        elif name == "one_euro":
            return self.items.filter(value=1, check=False).first()
        elif name == "two_euros":
            return self.items.filter(value=2, check=False).first()
        elif name == "five_euros":
            return self.items.filter(value=5, check=False).first()
        elif name == "ten_euros":
            return self.items.filter(value=10, check=False).first()
        elif name == "twenty_euros":
            return self.items.filter(value=20, check=False).first()
        elif name == "fifty_euros":
            return self.items.filter(value=50, check=False).first()
        elif name == "hundred_euros":
            return self.items.filter(value=100, check=False).first()
        elif name == "check_1":
            return checks[0] if 0 < len(checks) else None
        elif name == "check_2":
            return checks[1] if 1 < len(checks) else None
        elif name == "check_3":
            return checks[2] if 2 < len(checks) else None
        elif name == "check_4":
            return checks[3] if 3 < len(checks) else None
        elif name == "check_5":
            return checks[4] if 4 < len(checks) else None
        else:
            return object.__getattribute__(self, name)

    def is_owned_by(self, user):
        """
        Method to see if that object can be edited by the given user
        """
        if user.is_anonymous:
            return False
        if user.is_in_group(pk=settings.SITH_GROUP_COUNTER_ADMIN_ID):
            return True
        return False

    def get_total(self):
        t = 0
        for it in self.items.all():
            t += it.quantity * it.value
        return t

    def save(self, *args, **kwargs):
        if not self.id:
            self.date = timezone.now()
        return super(CashRegisterSummary, self).save(*args, **kwargs)

    def get_absolute_url(self):
        return reverse("counter:cash_summary_list")


class CashRegisterSummaryItem(models.Model):
    cash_summary = models.ForeignKey(
        CashRegisterSummary,
        related_name="items",
        verbose_name=_("cash summary"),
        on_delete=models.CASCADE,
    )
    value = CurrencyField(_("value"))
    quantity = models.IntegerField(_("quantity"), default=0)
    check = models.BooleanField(_("check"), default=False)

    class Meta:
        verbose_name = _("cash register summary item")


class Eticket(models.Model):
    """
    Eticket can be linked to a product an allows PDF generation
    """

    product = models.OneToOneField(
        Product,
        related_name="eticket",
        verbose_name=_("product"),
        on_delete=models.CASCADE,
    )
    banner = models.ImageField(
        upload_to="etickets", null=True, blank=True, verbose_name=_("banner")
    )
    event_date = models.DateField(_("event date"), null=True, blank=True)
    event_title = models.CharField(
        _("event title"), max_length=64, null=True, blank=True
    )
    secret = models.CharField(_("secret"), max_length=64, unique=True)

    def __str__(self):
        return "%s" % (self.product.name)

    def get_absolute_url(self):
        return reverse("counter:eticket_list")

    def save(self, *args, **kwargs):
        if not self.id:
            self.secret = base64.b64encode(os.urandom(32))
        return super(Eticket, self).save(*args, **kwargs)

    def is_owned_by(self, user):
        """
        Method to see if that object can be edited by the given user
        """
        if user.is_anonymous:
            return False
        return user.is_in_group(pk=settings.SITH_GROUP_COUNTER_ADMIN_ID)

    def get_hash(self, string):
        import hashlib
        import hmac

        return hmac.new(
            bytes(self.secret, "utf-8"), bytes(string, "utf-8"), hashlib.sha1
        ).hexdigest()


class StudentCard(models.Model):
    """
    Alternative way to connect a customer into a counter
    We are using Mifare DESFire EV1 specs since it's used for izly cards
    https://www.nxp.com/docs/en/application-note/AN10927.pdf
    UID is 7 byte long that means 14 hexa characters
    """

    UID_SIZE = 14

    @staticmethod
    def is_valid(uid):
        return (
            (uid.isupper() or uid.isnumeric())
            and len(uid) == StudentCard.UID_SIZE
            and not StudentCard.objects.filter(uid=uid).exists()
        )

    @staticmethod
    def can_create(customer, user):
        return user.pk == customer.user.pk or user.is_board_member or user.is_root

    def can_be_edited_by(self, obj):
        if isinstance(obj, User):
            return StudentCard.can_create(self.customer, obj)
        return False

    uid = models.CharField(
        _("uid"), max_length=14, unique=True, validators=[MinLengthValidator(4)]
    )
    customer = models.ForeignKey(
        Customer,
        related_name="student_cards",
        verbose_name=_("student cards"),
        null=False,
        blank=False,
        on_delete=models.CASCADE,
    )