Implement discount (promo) codes

backend/clubs/migrations/0120_ticket_code_discount_ticket_discount_code_applied.py

@@ -0,0 +1,24 @@
+# Generated by Django 5.1 on 2025-03-23 22:43
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("clubs", "0119_registrationqueuesettings"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="ticket",
+            name="code_discount",
+            field=models.DecimalField(blank=True, decimal_places=2,
+                                      default=0, max_digits=3),
+        ),
+        migrations.AddField(
+            model_name="ticket",
+            name="discount_code_applied",
+            field=models.BooleanField(default=False),
+        ),
+    ]

backend/clubs/models.py

@@ -1,4 +1,5 @@
 import datetime
+import hashlib
 import os
 import re
 import uuid
@@ -1896,6 +1897,14 @@ class TicketTransactionRecord(models.Model):
     buyer_email = models.EmailField(blank=True, null=True)
 
 
+def get_discount_code(event, ticket):
+    # get private key as hash of event id, ticket class, and secret
+    private_key = hashlib.sha256(
+        f"{event.id}-{ticket.type}-{settings.SECRET_KEY}".encode()
+    ).hexdigest()
+    return private_key[:8].upper()
+
+
 class Ticket(models.Model):
     """
     Represents an instance of a ticket for an event
@@ -1930,6 +1939,13 @@ class Ticket(models.Model):
         blank=True,
     )
     group_size = models.PositiveIntegerField(null=True, blank=True)
+    code_discount = models.DecimalField(
+        max_digits=3,
+        decimal_places=2,
+        default=0,
+        blank=True,
+    )
+    discount_code_applied = models.BooleanField(default=False)
     transferable = models.BooleanField(default=True)
     attended = models.BooleanField(default=False)
     # TODO: change to enum between All, Club, None
@@ -1993,6 +2009,10 @@ def send_confirmation_email(self):
                 },
             )
 
+    @property
+    def discount_code(self):
+        return get_discount_code(self.event, self)
+
 
 class TicketTransferRecord(models.Model):
     """

backend/clubs/serializers.py

@@ -1804,13 +1804,42 @@ class TicketSerializer(serializers.ModelSerializer):
 
     owner = serializers.SerializerMethodField("get_owner_name")
     event = EventSerializer()
+    discount_code = serializers.SerializerMethodField()
 
     def get_owner_name(self, obj):
         return obj.owner.get_full_name() if obj.owner else "None"
 
+    def get_discount_code(self, obj):
+        # only event officers should be able to see discount codes
+        if (
+            "request" in self.context
+            and self.context["request"].user.is_authenticated
+            and (
+                membership := Membership.objects.filter(
+                    person=self.context["request"].user, club=obj.event.club
+                ).first()
+            )
+        ):
+            if membership.role <= Membership.ROLE_OFFICER:
+                return obj.discount_code
+        return None
+
     class Meta:
         model = Ticket
-        fields = ("id", "event", "type", "owner", "attended", "price")
+        fields = (
+            "id",
+            "event",
+            "type",
+            "owner",
+            "attended",
+            "price",
+            "buyable",
+            "code_discount",
+            "group_discount",
+            "group_size",
+            "discount_code",
+            "discount_code_applied",
+        )
 
 
 class UserUUIDSerializer(serializers.ModelSerializer):

backend/clubs/views.py

@@ -46,7 +46,6 @@
     DurationField,
     ExpressionWrapper,
     F,
-    Max,
     Prefetch,
     Q,
     TextField,
@@ -2539,6 +2538,9 @@ def add_to_cart(self, request, *args, **kwargs):
                                             type: string
                                         count:
                                             type: integer
+                                        discount_code:
+                                            type: string
+                                            required: false
         responses:
             "200":
                 content:
@@ -2620,6 +2622,7 @@ def add_to_cart(self, request, *args, **kwargs):
         for item in quantities:
             type = item["type"]
             count = item["count"]
+            discount_code = item.get("discount_code", None)
 
             # Count unowned/unheld tickets of requested type
             # We don't need a lock since we aren't changing the holder or owner
@@ -2643,6 +2646,18 @@ def add_to_cart(self, request, *args, **kwargs):
                     },
                     status=status.HTTP_403_FORBIDDEN,
                 )
+
+            if discount_code:
+                valid_discount_code = tickets.first().discount_code
+                if discount_code != valid_discount_code:
+                    return Response(
+                        {
+                            "detail": f"Invalid discount code for {type}",
+                            "success": False,
+                        },
+                        status=status.HTTP_400_BAD_REQUEST,
+                    )
+                tickets.update(discount_code_applied=True)
             cart.tickets.add(*tickets[:count])
 
         cart.save()
@@ -2783,6 +2798,13 @@ def tickets(self, request, *args, **kwargs):
                                                 type: integer
                                             price:
                                                 type: number
+                                            code_discount:
+                                                type: number
+                                            group_discount:
+                                                type: number
+                                            group_size:
+                                                type: number
+                                                required: false
                                 available:
                                     type: array
                                     items:
@@ -2794,26 +2816,60 @@ def tickets(self, request, *args, **kwargs):
                                                 type: integer
                                             price:
                                                 type: number
+                                            code_discount:
+                                                type: number
+                                            group_discount:
+                                                type: number
+                                            group_size:
+                                                type: number
         ---
         """
         event = self.get_object()
         tickets = Ticket.objects.filter(event=event)
+        # if for purchasing purposes, non-buyable tickets are unavailable
+        # otherwise, all non-owned/held tickets are available
+        for_purchasing = self.request.query_params.get("for_purchasing", "true")
 
         # Take price of first ticket of given type for now
-        totals = (
-            tickets.values("type")
-            .annotate(price=Max("price"))
-            .annotate(count=Count("type"))
-            .order_by("type")
-        )
-        available = (
-            tickets.filter(owner__isnull=True, holder__isnull=True, buyable=True)
-            .values("type")
-            .annotate(price=Max("price"))
-            .annotate(count=Count("type"))
-            .order_by("type")
+        total_counts = {
+            t["type"]: t["count"]
+            for t in tickets.values("type").annotate(count=Count("type"))
+        }
+
+        available_tickets = tickets.filter(
+            owner__isnull=True,
+            holder__isnull=True,
         )
-        return Response({"totals": list(totals), "available": list(available)})
+        if for_purchasing == "true":
+            available_tickets = available_tickets.filter(buyable=True)
+        available_counts = {
+            t["type"]: t["count"]
+            for t in available_tickets.values("type").annotate(count=Count("type"))
+        }
+
+        # Get one representative ticket for each type and serialize it
+        totals_list = []
+        available_list = []
+        for ticket_type in tickets.values_list("type", flat=True).distinct():
+            ticket = tickets.filter(type=ticket_type).first()
+            if ticket:
+                # Serialize the ticket and add counts
+                ticket_data = TicketSerializer(
+                    ticket, context={"request": request}
+                ).data
+
+                # Add to totals
+                totals_entry = ticket_data.copy()
+                totals_entry["count"] = total_counts.get(ticket_type, 0)
+                totals_list.append(totals_entry)
+
+                # Add to available if there are any available tickets
+                if ticket_type in available_counts:
+                    available_entry = ticket_data.copy()
+                    available_entry["count"] = available_counts.get(ticket_type, 0)
+                    available_list.append(available_entry)
+
+        return Response({"totals": totals_list, "available": available_list})
 
     @tickets.mapping.put
     @transaction.atomic
@@ -2845,6 +2901,10 @@ def create_tickets(self, request, *args, **kwargs):
                                             type: number
                                             format: float
                                             required: false
+                                        code_discount:
+                                            type: number
+                                            format: float
+                                            required: false
                                         transferable:
                                             type: boolean
                                         buyable:
@@ -2929,14 +2989,25 @@ def create_tickets(self, request, *args, **kwargs):
                 )
 
             # Group discounts must be between 0 and 1
-            if item.get("group_discount", 0) < 0 or item.get("group_discount", 0) > 1:
+            if item.get("group_discount", 0) is not None and (
+                item.get("group_discount", 0) < 0 or item.get("group_discount", 0) > 1
+            ):
                 return Response(
                     {"detail": "Group discount must be between 0 and 1"},
                     status=status.HTTP_400_BAD_REQUEST,
                 )
 
+            # Code discounts must be between 0 and 1
+            if item.get("code_discount", 0) is not None and (
+                item.get("code_discount", 0) < 0 or item.get("code_discount", 0) > 1
+            ):
+                return Response(
+                    {"detail": "Code discount must be between 0 and 1"},
+                    status=status.HTTP_400_BAD_REQUEST,
+                )
+
             # Min group sizes must be greater than 1
-            if item.get("group_size", 2) <= 1:
+            if item.get("group_size", 2) is not None and item.get("group_size", 2) <= 1:
                 return Response(
                     {"detail": "Min group size must be greater than 1"},
                     status=status.HTTP_400_BAD_REQUEST,
@@ -2961,8 +3032,9 @@ def create_tickets(self, request, *args, **kwargs):
                 event=event,
                 type=item["type"],
                 price=item.get("price", 0),
-                group_discount=item.get("group_discount", 0),
+                group_discount=item.get("group_discount", 0) or 0,  # Field not nullable
                 group_size=item.get("group_size", None),
+                code_discount=item.get("code_discount", 0) or 0,
                 transferable=item.get("transferable", True),
                 buyable=item.get("buyable", True),
             )
@@ -5548,6 +5620,14 @@ def _calculate_cart_total(cart) -> float:
                 and ticket_type_counts[ticket.type] >= ticket.group_size
                 else ticket.price
             )
+            * (
+                1
+                - (
+                    ticket.code_discount
+                    if ticket.code_discount and ticket.discount_code_applied
+                    else 0
+                )
+            )
             for ticket in cart.tickets.all()
         )
         return cart_total