feat: Add like endpoint for promo codes

promo_code/business/migrations/0003_promo_like_count.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.2 on 2025-05-13 19:41
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("business", "0002_promo_used_count_alter_company_token_version_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="promo",
+            name="like_count",
+            field=models.PositiveIntegerField(default=0, editable=False),
+        ),
+    ]

promo_code/business/models.py

@@ -64,6 +64,10 @@ class Promo(django.db.models.Model):
         default=0,
         editable=False,
     )
+    like_count = django.db.models.PositiveIntegerField(
+        default=0,
+        editable=False,
+    )
     active_from = django.db.models.DateField(null=True, blank=True)
     active_until = django.db.models.DateField(null=True, blank=True)
     mode = django.db.models.CharField(
@@ -99,6 +103,10 @@ def is_active(self) -> bool:
 
         return True
 
+    @property
+    def get_like_count(self) -> int:
+        return self.like_count
+
     @property
     def get_used_codes_count(self) -> int:
         if self.mode == business.constants.PROMO_MODE_UNIQUE:

promo_code/business/serializers.py

@@ -406,7 +406,10 @@ class PromoReadOnlySerializer(rest_framework.serializers.ModelSerializer):
     target = TargetSerializer()
 
     promo_unique = rest_framework.serializers.SerializerMethodField()
-    like_count = rest_framework.serializers.SerializerMethodField()
+    like_count = rest_framework.serializers.IntegerField(
+        source='get_like_count',
+        read_only=True,
+    )
     used_count = rest_framework.serializers.IntegerField(
         source='get_used_codes_count',
         read_only=True,
@@ -439,10 +442,6 @@ class Meta:
     def get_promo_unique(self, obj):
         return obj.get_available_unique_codes
 
-    def get_like_count(self, obj):
-        # TODO
-        return 0
-
     def to_representation(self, instance):
         data = super().to_representation(instance)
         if instance.mode == business.constants.PROMO_MODE_COMMON:
@@ -476,7 +475,10 @@ class PromoDetailSerializer(rest_framework.serializers.ModelSerializer):
         source='company.name',
         read_only=True,
     )
-    like_count = rest_framework.serializers.SerializerMethodField()
+    like_count = rest_framework.serializers.IntegerField(
+        source='get_like_count',
+        read_only=True,
+    )
     used_count = rest_framework.serializers.IntegerField(
         source='get_used_codes_count',
         read_only=True,
@@ -526,7 +528,3 @@ def validate(self, data):
             instance=self.instance,
         )
         return validator.validate()
-
-    def get_like_count(self, obj):
-        # TODO
-        return 0

promo_code/user/migrations/0002_promolike.py

@@ -0,0 +1,56 @@
+# Generated by Django 5.2 on 2025-05-12 17:44
+
+import django.db.models.deletion
+import uuid
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("business", "0002_promo_used_count_alter_company_token_version_and_more"),
+        ("user", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="PromoLike",
+            fields=[
+                (
+                    "id",
+                    models.UUIDField(
+                        default=uuid.uuid4,
+                        editable=False,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="UUID",
+                    ),
+                ),
+                ("created_at", models.DateTimeField(auto_now_add=True)),
+                (
+                    "promo",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="likes",
+                        to="business.promo",
+                    ),
+                ),
+                (
+                    "user",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="promo_likes",
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+            ],
+            options={
+                "constraints": [
+                    models.UniqueConstraint(
+                        fields=("user", "promo"), name="unique_like"
+                    )
+                ],
+            },
+        ),
+    ]

promo_code/user/models.py

@@ -4,6 +4,7 @@
 import django.db.models
 import django.utils.timezone
 
+import business.models
 import user.constants
 
 
@@ -82,3 +83,34 @@ def save(self, *args, **kwargs):
             self.last_login = django.utils.timezone.now()
 
         super().save(*args, **kwargs)
+
+
+class PromoLike(django.db.models.Model):
+    id = django.db.models.UUIDField(
+        'UUID',
+        primary_key=True,
+        default=uuid.uuid4,
+        editable=False,
+    )
+    user = django.db.models.ForeignKey(
+        User,
+        on_delete=django.db.models.CASCADE,
+        related_name='promo_likes',
+    )
+    promo = django.db.models.ForeignKey(
+        business.models.Promo,
+        on_delete=django.db.models.CASCADE,
+        related_name='likes',
+    )
+    created_at = django.db.models.DateTimeField(auto_now_add=True)
+
+    class Meta:
+        constraints = [
+            django.db.models.UniqueConstraint(
+                fields=['user', 'promo'],
+                name='unique_like',
+            ),
+        ]
+
+    def __str__(self):
+        return f'{self.user} likes {self.promo}'

promo_code/user/serializers.py

@@ -342,7 +342,10 @@ class PromoFeedSerializer(rest_framework.serializers.ModelSerializer):
     active = rest_framework.serializers.BooleanField(source='is_active')
     is_activated_by_user = rest_framework.serializers.SerializerMethodField()
     is_liked_by_user = rest_framework.serializers.SerializerMethodField()
-    like_count = rest_framework.serializers.SerializerMethodField()
+    like_count = rest_framework.serializers.IntegerField(
+        source='get_like_count',
+        read_only=True,
+    )
     comment_count = rest_framework.serializers.SerializerMethodField()
 
     class Meta:
@@ -366,10 +369,6 @@ def get_is_activated_by_user(self, obj) -> bool:
         # TODO:
         return False
 
-    def get_like_count(self, obj) -> int:
-        # TODO:
-        return 0
-
     def get_is_liked_by_user(self, obj) -> bool:
         # TODO:
         return False
@@ -403,7 +402,10 @@ class UserPromoDetailSerializer(rest_framework.serializers.ModelSerializer):
         read_only=True,
     )
     is_activated_by_user = rest_framework.serializers.SerializerMethodField()
-    like_count = rest_framework.serializers.SerializerMethodField()
+    like_count = rest_framework.serializers.IntegerField(
+        source='get_like_count',
+        read_only=True,
+    )
     is_liked_by_user = rest_framework.serializers.SerializerMethodField()
     comment_count = rest_framework.serializers.SerializerMethodField()
 
@@ -423,15 +425,20 @@ class Meta:
         )
         read_only_fields = fields
 
-    def get_is_activated_by_user(self, obj) -> bool:
-        # TODO:
+    def get_is_liked_by_user(self, obj: business.models.Promo) -> bool:
+        request = self.context.get('request')
+        if (
+            request
+            and hasattr(request, 'user')
+            and request.user.is_authenticated
+        ):
+            return user.models.PromoLike.objects.filter(
+                promo=obj,
+                user=request.user,
+            ).exists()
         return False
 
-    def get_like_count(self, obj) -> int:
-        # TODO:
-        return 0
-
-    def get_is_liked_by_user(self, obj) -> bool:
+    def get_is_activated_by_user(self, obj) -> bool:
         # TODO:
         return False
 

promo_code/user/urls.py

@@ -37,4 +37,9 @@
         user.views.UserPromoDetailView.as_view(),
         name='user-promo-detail',
     ),
+    django.urls.path(
+        'promo/<uuid:id>/like',
+        user.views.UserPromoLikeView.as_view(),
+        name='user-promo-like',
+    ),
 ]

promo_code/user/views.py

@@ -1,14 +1,17 @@
 import django.db.models
+import django.shortcuts
 import django.utils.timezone
 import rest_framework.generics
 import rest_framework.permissions
 import rest_framework.response
 import rest_framework.status
+import rest_framework.views
 import rest_framework_simplejwt.tokens
 import rest_framework_simplejwt.views
 
 import business.constants
 import business.models
+import user.models
 import user.pagination
 import user.serializers
 
@@ -224,3 +227,52 @@ def list(self, request, *args, **kwargs):
         self.validated_query_params = query_serializer.validated_data
 
         return super().list(request, *args, **kwargs)
+
+
+class UserPromoLikeView(rest_framework.views.APIView):
+    permission_classes = [rest_framework.permissions.IsAuthenticated]
+
+    def get_promo_object(self, promo_id):
+        return django.shortcuts.get_object_or_404(
+            business.models.Promo,
+            id=promo_id,
+        )
+
+    def post(self, request, id):
+        """Add a like to the promo code."""
+        promo = self.get_promo_object(id)
+
+        created = user.models.PromoLike.objects.get_or_create(
+            user=request.user,
+            promo=promo,
+        )
+
+        if created:
+            promo.like_count = django.db.models.F('like_count') + 1
+            promo.save(update_fields=['like_count'])
+
+        return rest_framework.response.Response(
+            {'status': 'ok'},
+            status=rest_framework.status.HTTP_200_OK,
+        )
+
+    def delete(self, request, id):
+        """Remove a like from the promo code."""
+        promo = self.get_promo_object(id)
+
+        # Idempotency: if the like doesn't exist,
+        # do nothing and still return 200 OK.
+        like_instance = user.models.PromoLike.objects.filter(
+            user=request.user,
+            promo=promo,
+        ).first()
+
+        if like_instance:
+            like_instance.delete()
+            promo.like_count = django.db.models.F('like_count') - 1
+            promo.save(update_fields=['like_count'])
+
+        return rest_framework.response.Response(
+            {'status': 'ok'},
+            status=rest_framework.status.HTTP_200_OK,
+        )