Add discounts (#182)

* Add discounts

Author: KwikKill

docs/manuel/src/03-existant/modules/payment.md

@@ -20,6 +20,14 @@ automatiquement à la création d'un tournoi (et plus tard, d'un créneau pizza)
 Ils contiennent plusieurs info comme le nom, le prix, la description, les dates
 de début et de fin de vente, etc.
 
+## Discount
+
+Les réductions sont créées manuellement par les admins. Elles font le lien entre
+un utilisateur et un produit. La valeur de la réduction et une description sont
+également stockées dans ce modèle. Les réductions doivent être ajoutés en amont
+du paiement et peuvent être utilisées une seule fois. Cela peut permettre de
+réduire le prix d'un pour certains joueurs. 
+
 ## Transaction
 
 Les transactions sont créées à chaque fois qu'un utilisateur initie un paiement

insalan/payment/admin.py

@@ -8,7 +8,7 @@
 from django.http import HttpResponse
 from django.utils.translation import gettext_lazy as _
 
-from .models import Product, Transaction, Payment, TransactionStatus
+from .models import Product, Transaction, Payment, TransactionStatus, Discount
 
 
 class ProductAdmin(admin.ModelAdmin):
@@ -123,3 +123,15 @@ def has_delete_permission(self, _request, _obj=None):
 
 
 admin.site.register(Transaction, TransactionAdmin)
+
+class DiscountAdmin(admin.ModelAdmin):
+    """
+    Admin handler for Discounts
+    """
+
+    list_display = ("id", "discount", "user", "product", "used")
+    search_fields = ["id", "discount", "user", "product", "reason"]
+    
+
+
+admin.site.register(Discount, DiscountAdmin)

insalan/payment/models.py

@@ -10,6 +10,7 @@
 from django.db import models
 from django.utils.translation import gettext_lazy as _
 from django.utils import timezone
+from django.core.validators import MinValueValidator
 from rest_framework.serializers import ValidationError
 
 import insalan.settings as app_settings
@@ -85,6 +86,12 @@ def can_be_bought_now(self) -> bool:
         """Returns whether or not the product can be bought now"""
         return self.available_from <= timezone.now() <= self.available_until
 
+    def __str__(self):
+        """
+        Return the name of the product
+        """
+        return str(self.name)
+
 
 class Payment(models.Model):
     """
@@ -161,6 +168,11 @@ class Meta:
         decimal_places=2,
         verbose_name=_("Montant"),
     )
+    discounts = models.ManyToManyField(
+        "Discount",
+        blank=True,
+        verbose_name=_("Réductions")
+    )
 
     @staticmethod
     def new(**data):
@@ -326,6 +338,10 @@ def validate_transaction(self):
 
         self.payment_status = TransactionStatus.SUCCEEDED
         self.last_modification_date = timezone.make_aware(datetime.now())
+        # For each discount, mark it as used
+        for discount in self.discounts.all():
+            discount.use()
+
         self.save()
         logger.info("Transaction %s succeeded", self.id)
         self.run_success_hooks()
@@ -378,3 +394,57 @@ class Meta:
         null=True,
     )
     count = models.IntegerField(default=1, editable=True, verbose_name=_("Quantité"))
+
+# Discount
+
+class DiscountAlreadyUsedError(Exception):
+    """Error raised when trying to use an already used discount"""
+
+class Discount(models.Model):
+    """
+    A discount is a temporary reduction of the price of a product
+    
+    A discount is tied to a user, a product and can be used only once
+    """
+
+    class Meta:
+        """Meta information"""
+
+        verbose_name = _("Réduction")
+        verbose_name_plural = _("Réductions")
+
+    id: int
+    user = models.ForeignKey(
+        User, null=True, on_delete=models.SET_NULL, verbose_name=_("Utilisateur")
+    )
+    product = models.ForeignKey(
+        Product, null=True, on_delete=models.SET_NULL, verbose_name=_("Produit")
+    )
+    discount = models.DecimalField(
+        null=False,
+        max_digits=5,
+        decimal_places=2,
+        verbose_name=_("Réduction"),
+        validators=[MinValueValidator(Decimal('0.01'))]
+    )
+    reason = models.CharField(max_length=200, verbose_name=_("Motif"))
+    creation_date = models.DateTimeField(
+        verbose_name=_("Date de création"),
+        editable=False,
+        default=timezone.now
+    )
+    used = models.BooleanField(default=False, verbose_name=_("Utilisé"))
+    used_date = models.DateTimeField(
+        verbose_name=_("Date d'utilisation"),
+        editable=False,
+        null=True,
+        blank=True
+    )
+
+    def use(self):
+        """Use the discount"""
+        if self.used:
+            raise DiscountAlreadyUsedError("Discount already used")
+        self.used = True
+        self.used_date = timezone.make_aware(datetime.now())
+        self.save()

insalan/payment/views.py

@@ -19,7 +19,7 @@
 import insalan.settings as app_settings
 import insalan.payment.serializers as serializers
 
-from .models import Transaction, TransactionStatus, Product, Payment
+from .models import Transaction, TransactionStatus, Product, Payment, Discount
 from .tokens import Token
 
 logger = logging.getLogger(__name__)
@@ -425,9 +425,22 @@ def create(self, request):
                     status=status.HTTP_400_BAD_REQUEST,
                 )
 
+            amount = transaction_obj.amount
+
+            # If the user has a discount for some products, apply them
+            for product in transaction_obj.products.all():
+                discounts = Discount.objects.filter(user=payer, product=product, used=False)
+                for discount in discounts:
+                    # Check if the discount is applicable
+                    if amount >= discount.discount:
+                        amount -= discount.discount
+
+                        # Add the discount to the transaction object
+                        transaction_obj.discounts.add(discount)
+
             # helloasso intent
             helloasso_amount = int(
-                transaction_obj.amount * 100
+                amount * 100
             )  # helloasso reads prices in cents
             intent_body = {
                 "totalAmount": helloasso_amount,

insalan/tournament/models/tournament.py

@@ -202,7 +202,7 @@ def save(self, *args, **kwargs):
         if self.player_online_product is None:
             prod = Product.objects.create(
                 price=self.player_price_online,
-                name=_(f"Place {self.name} Joueur en ligne"),
+                name=_(f"Place {self.name} Joueur en ligne - {self.event.name}"),
                 desc=_(f"Inscription au tournoi {self.name} joueur"),
                 category=ProductCategory.REGISTRATION_PLAYER,
                 associated_tournament=self,
@@ -219,7 +219,7 @@ def save(self, *args, **kwargs):
         if self.manager_online_product is None:
             prod = Product.objects.create(
                 price=self.manager_price_online,
-                name=_(f"Place {self.name} manager en ligne"),
+                name=_(f"Place {self.name} manager en ligne - {self.event.name}"),
                 desc=_(f"Inscription au tournoi {self.name} manager"),
                 category=ProductCategory.REGISTRATION_MANAGER,
                 associated_tournament=self,
@@ -236,7 +236,7 @@ def save(self, *args, **kwargs):
         if self.substitute_online_product is None:
             prod = Product.objects.create(
                 price=self.substitute_price_online,
-                name=_(f"Place {self.name} remplaçant en ligne"),
+                name=_(f"Place {self.name} remplaçant en ligne - {self.event.name}"),
                 desc=_(f"Inscription au tournoi {self.name} remplaçant"),
                 category=ProductCategory.REGISTRATION_SUBSTITUTE,
                 associated_tournament=self,