Add backend for bookable office hours

backend/Pipfile

@@ -41,11 +41,11 @@ channels = "==3.0.5"
 channels-redis = "*"
 uvicorn = {extras = ["standard"],version = "*"}
 gunicorn = "*"
-django-schedules-ohq = "*"
 typing-extensions = "*"
 drf-excel = "*"
 pytz = "*"
 inflection = "*"
+django-scheduler = {git = "https://github.com/llazzaro/django-scheduler.git", ref = "8aa6f877f17e5b05f17d7c39e93d8e73625b0a65"}
 
 [requires]
 python_version = "3.11"

backend/ohq/admin.py

@@ -13,6 +13,7 @@
     Semester,
     Tag,
     UserStatistic,
+    Booking,
 )
 
 
@@ -28,3 +29,4 @@
 admin.site.register(Announcement)
 admin.site.register(Tag)
 admin.site.register(UserStatistic)
+admin.site.register(Booking)

backend/ohq/migrations/0022_booking.py

@@ -0,0 +1,56 @@
+# Generated by Django 5.0.3 on 2025-03-30 19:21
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("ohq", "0021_queue_question_timer_enabled_and_more"),
+        ("schedule", "0031_occurrence_location"),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="Booking",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("start", models.DateTimeField(db_index=True, verbose_name="start")),
+                ("end", models.DateTimeField(db_index=True, verbose_name="end")),
+                (
+                    "occurrence",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="bookings",
+                        to="schedule.occurrence",
+                    ),
+                ),
+                (
+                    "user",
+                    models.ForeignKey(
+                        blank=True,
+                        null=True,
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+            ],
+            options={
+                "verbose_name": "booking",
+                "verbose_name_plural": "bookings",
+                "ordering": ["start"],
+                "index_together": {("start", "end")},
+            },
+        ),
+    ]

backend/ohq/models.py

@@ -1,10 +1,11 @@
 from django.conf import settings
 from django.core.validators import MaxValueValidator, MinValueValidator
+from django.core.exceptions import ValidationError
 from django.db import models
 from django.dispatch import receiver
 from email_tools.emails import send_email
 from phonenumber_field.modelfields import PhoneNumberField
-
+from schedule.models import Event, Occurrence
 
 User = settings.AUTH_USER_MODEL
 
@@ -447,3 +448,71 @@ class Meta:
 
     def __str__(self):
         return f"{self.user}: {self.metric}"
+
+class Booking(models.Model):
+    """
+    Booking within an occurrence.
+    Bookings can only be created with start times of 5-minute intervals.
+    """
+
+    occurrence = models.ForeignKey(Occurrence, on_delete=models.CASCADE, related_name="bookings")
+    user = models.ForeignKey(User, on_delete=models.CASCADE, blank=True, null=True)
+    start = models.DateTimeField("start", db_index=True)
+    end = models.DateTimeField("end", db_index=True)
+
+    class Meta:
+        verbose_name = ("booking")
+        verbose_name_plural = ("bookings")
+        ordering = ["start"]
+        index_together = (("start", "end"),)
+
+    def clean(self):
+        if self.start >= self.end:
+            raise ValidationError('Start time must be before end time.')
+
+        if self.start.minute % 5 != 0:
+            raise ValidationError('Start time must be on a 5-minute interval (e.g., :00, :05, :10, :15, etc).')
+
+        if self.start < self.occurrence.start or self.end > self.occurrence.end:
+            raise ValidationError('Booking times must be within the occurrence\'s start and end times.')
+
+        duration = self.end - self.start
+        duration_minutes = duration.total_seconds() / 60
+
+        if duration_minutes != self.occurrence.interval:
+            raise ValidationError(f'Booking duration must be {self.occurrence.interval} minutes.')
+
+        overlapping_bookings = Booking.objects.filter(
+            occurrence=self.occurrence,
+            start__lt=self.end,
+            end__gt=self.start
+        ).exclude(id=self.id)
+        if overlapping_bookings.exists():
+            raise ValidationError('Booking times cannot overlap with existing bookings.')
+
+        super().clean()
+
+    def save(self, *args, **kwargs):
+        self.clean()
+        super().save(*args, **kwargs)
+
+    def __str__(self):
+        start_str = self.start.strftime("%Y-%m-%d %H:%M:%S")
+        end_str = self.end.strftime("%Y-%m-%d %H:%M:%S")
+        return f"{start_str} to {end_str}"
+
+Event.add_to_class('location', models.CharField(max_length=255, blank=True))
+Occurrence.add_to_class('location', models.CharField(max_length=255, blank=True))
+Occurrence.add_to_class('interval', models.IntegerField(blank=True, null=True))
+
+def new_occurrence_init(self, *args, **kwargs):
+    super(Occurrence, self).__init__(*args, **kwargs)
+    event = kwargs.get("event", None)
+    if not self.title and event:
+        self.title = event.title
+    if not self.description and event:
+        self.description = event.description
+    if not self.location and event:
+        self.location = event.location
+
+Occurrence.__init__ = new_occurrence_init

backend/ohq/permissions.py

@@ -1,9 +1,12 @@
 from django.db.models import Q
 from rest_framework import permissions
 from schedule.models import Event, EventRelation, Occurrence
-
-from ohq.models import Course, Membership, Question
-
+from ohq.models import (
+    Course, 
+    Membership, 
+    Question, 
+    Booking,
+)
 
 # Hierarchy of permissions is usually:
 # Professor > Head TA > TA > Student > User
@@ -504,3 +507,44 @@ def has_permission(self, request, view):
             return True
 
         return True
+
+class BookingPermission(permissions.BasePermission):
+    @staticmethod
+    def get_membership_from_occurrence(request, occurrence):
+        event_course_relation = EventRelation.objects.filter(event=occurrence.event).first()
+        membership = Membership.objects.filter(
+            course_id=event_course_relation.object_id, user=request.user
+        ).first()
+        return membership
+
+    def has_object_permission(self, request, view, obj):
+        if view.action in ["retrieve"]:
+            booking = Booking.objects.filter(pk=view.kwargs["pk"]).first()
+            membership = self.get_membership_from_occurrence(request=request, occurrence=booking.occurrence)
+            return membership is not None
+
+        if view.action in ["update", "partial_update", "destroy"]:
+            booking = Booking.objects.filter(pk=view.kwargs["pk"]).first()
+            membership = self.get_membership_from_occurrence(request=request, occurrence=booking.occurrence)
+
+            if membership is None:
+                return False
+
+            if membership.is_ta:
+                return True
+
+            return booking.user == request.user
+
+        return False
+
+    def has_permission(self, request, view):
+        if not request.user.is_authenticated:
+            return False
+
+        if view.action in ["list", "create"]:
+            occurrence_id = view.kwargs.get("occurrence_pk")
+            occurrence = Occurrence.objects.filter(id=occurrence_id).first()
+            membership = self.get_membership_from_occurrence(request=request, occurrence=occurrence)
+            return membership is not None
+
+        return True

backend/ohq/serializers.py

@@ -7,8 +7,7 @@
 from phonenumber_field.serializerfields import PhoneNumberField
 from rest_framework import serializers
 from rest_live.signals import save_handler
-from schedule.models import Calendar, Event, EventRelation, EventRelationManager, Rule
-from schedule.models.events import Occurrence
+from schedule.models import Calendar, Event, Occurrence, EventRelation, EventRelationManager, Rule
 
 from ohq.models import (
     Announcement,
@@ -22,6 +21,7 @@
     QueueStatistic,
     Semester,
     Tag,
+    Booking,
 )
 from ohq.sms import sendSMSVerification
 from ohq.tasks import sendUpNextNotificationTask
@@ -542,7 +542,7 @@ def update(self, instance, validated_data):
                 else:
                     rule, _ = Rule.objects.get_or_create(
                         frequency=validated_data["rule"]["frequency"],
-                        params=validated_data["rule"]["params"],
+                        params=validated_data["rule"].get("params", ""),
                     )
                 validated_data.pop("rule")
 
@@ -564,7 +564,7 @@ def create(self, validated_data):
         course = Course.objects.get(pk=validated_data["course_id"])
         rule = None
         if "rule" in validated_data and validated_data["rule"] is not None:
-            rule, _ = Rule.objects.get_or_create(frequency=validated_data["rule"]["frequency"], params = validated_data["rule"]["params"])
+            rule, _ = Rule.objects.get_or_create(frequency=validated_data["rule"]["frequency"], params = validated_data["rule"].get("params", ""))
             validated_data.pop("rule")
 
         validated_data.pop("course_id")
@@ -592,4 +592,16 @@ class OccurrenceSerializer(serializers.ModelSerializer):
 
     class Meta:
         model = Occurrence
-        fields = ("id", "title", "description", "location", "start", "end", "cancelled", "event")
+        fields = ("id", "title", "description", "location", "start", "end", "cancelled", "event", "interval")
+
+class BookingSerializer(serializers.ModelSerializer):
+    """
+    Serializer for booking
+    """
+
+    occurrence = OccurrenceSerializer(read_only=True)
+
+    class Meta:
+        model = Booking
+        fields = ("id", "occurrence", "user", "start", "end")  
+

backend/ohq/urls.py

@@ -19,6 +19,8 @@
     SemesterViewSet,
     TagViewSet,
     UserView,
+    BookingDetailViewSet,
+    BookingListCreateViewSet,
     HealthView,
 )
 
@@ -30,6 +32,10 @@
 router.register("courses", CourseViewSet, basename="course")
 router.register("events", EventViewSet, basename="event")
 router.register("occurrences", OccurrenceViewSet, basename="occurrence")
+router.register("bookings", BookingDetailViewSet, basename="booking")
+
+occurrence_router = routers.NestedSimpleRouter(router, "occurrences", lookup="occurrence")
+occurrence_router.register("bookings", BookingListCreateViewSet, basename="booking-create")
 
 course_router = routers.NestedSimpleRouter(router, "courses", lookup="course")
 course_router.register("queues", QueueViewSet, basename="queue")
@@ -65,4 +71,4 @@
     ),
 ]
 
-urlpatterns = router.urls + course_router.urls + queue_router.urls + additional_urls
+urlpatterns = router.urls + occurrence_router.urls + course_router.urls + queue_router.urls + additional_urls