solution

cinema/pagination.py

@@ -0,0 +1,7 @@
+from rest_framework.pagination import PageNumberPagination
+
+
+class CustomPagination(PageNumberPagination):
+    page_size = 5
+    page_size_query_param = "page_size"
+    max_page_size = 50

cinema/serializers.py

@@ -1,6 +1,15 @@
+from django.db import transaction
 from rest_framework import serializers
 
-from cinema.models import Genre, Actor, CinemaHall, Movie, MovieSession
+from cinema.models import (
+    Genre,
+    Actor,
+    CinemaHall,
+    Movie,
+    MovieSession,
+    Ticket,
+    Order
+)
 
 
 class GenreSerializer(serializers.ModelSerializer):
@@ -59,6 +68,7 @@ class MovieSessionListSerializer(MovieSessionSerializer):
     cinema_hall_capacity = serializers.IntegerField(
         source="cinema_hall.capacity", read_only=True
     )
+    tickets_available = serializers.IntegerField(read_only=True)
 
     class Meta:
         model = MovieSession
@@ -68,13 +78,73 @@ class Meta:
             "movie_title",
             "cinema_hall_name",
             "cinema_hall_capacity",
+            "tickets_available"
         )
 
 
+class TicketSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Ticket
+        fields = (
+            "id",
+            "row",
+            "seat",
+            "movie_session"
+        )
+
+
+class TicketListSerializer(TicketSerializer):
+    movie_session = MovieSessionListSerializer(many=False, read_only=True)
+
+
+class TicketTakenPlacesSerializer(TicketSerializer):
+    class Meta:
+        model = Ticket
+        fields = (
+            "row",
+            "seat",
+        )
+
+
+class OrderSerializer(serializers.ModelSerializer):
+    tickets = TicketSerializer(many=True, read_only=False, allow_empty=False)
+
+    class Meta:
+        model = Order
+        fields = ("id", "tickets", "created_at")
+
+    def create(self, validated_data):
+        with transaction.atomic():
+            tickets_data = validated_data.pop("tickets")
+            order = Order.objects.create(**validated_data)
+            for ticket_data in tickets_data:
+                Ticket.objects.create(order=order, **ticket_data)
+        return order
+
+
+class OrderListSerializer(OrderSerializer):
+    tickets = TicketListSerializer(many=True, read_only=True)
+
+
+class OrderDetailSerializer(OrderSerializer):
+    tickets = TicketListSerializer(many=True, read_only=True)
+
+
 class MovieSessionDetailSerializer(MovieSessionSerializer):
     movie = MovieListSerializer(many=False, read_only=True)
     cinema_hall = CinemaHallSerializer(many=False, read_only=True)
+    taken_places = TicketTakenPlacesSerializer(
+        many=True,
+        read_only=True,
+        source="tickets"
+    )
 
     class Meta:
         model = MovieSession
-        fields = ("id", "show_time", "movie", "cinema_hall")
+        fields = (
+            "id",
+            "show_time",
+            "movie",
+            "cinema_hall",
+            "taken_places"
+        )

cinema/urls.py

@@ -7,6 +7,7 @@
     CinemaHallViewSet,
     MovieViewSet,
     MovieSessionViewSet,
+    OrderViewSet
 )
 
 router = routers.DefaultRouter()
@@ -15,6 +16,7 @@
 router.register("cinema_halls", CinemaHallViewSet)
 router.register("movies", MovieViewSet)
 router.register("movie_sessions", MovieSessionViewSet)
+router.register("orders", OrderViewSet)
 
 urlpatterns = [path("", include(router.urls))]
 

cinema/views.py

@@ -1,6 +1,15 @@
+from django.db.models import Count, F
+
 from rest_framework import viewsets
 
-from cinema.models import Genre, Actor, CinemaHall, Movie, MovieSession
+from cinema.models import (
+    Genre,
+    Actor,
+    CinemaHall,
+    Movie,
+    MovieSession,
+    Order
+)
 
 from cinema.serializers import (
     GenreSerializer,
@@ -12,8 +21,13 @@
     MovieDetailSerializer,
     MovieSessionDetailSerializer,
     MovieListSerializer,
+    OrderSerializer,
+    OrderListSerializer,
+    OrderDetailSerializer
 )
 
+from .pagination import CustomPagination
+
 
 class GenreViewSet(viewsets.ModelViewSet):
     queryset = Genre.objects.all()
@@ -31,9 +45,33 @@ class CinemaHallViewSet(viewsets.ModelViewSet):
 
 
 class MovieViewSet(viewsets.ModelViewSet):
-    queryset = Movie.objects.all()
+    queryset = Movie.objects.prefetch_related("actors", "genres")
     serializer_class = MovieSerializer
 
+    @staticmethod
+    def params_to_ints(query_string: str) -> list[int]:
+        return [int(str_id) for str_id in query_string.split(",")]
+
+    def get_queryset(self):
+        queryset = self.queryset
+
+        actors = self.request.query_params.get("actors")
+        genres = self.request.query_params.get("genres")
+        title = self.request.query_params.get("title")
+
+        if title:
+            queryset = queryset.filter(title__icontains=title)
+
+        if genres:
+            genres = self.params_to_ints(genres)
+            queryset = queryset.filter(genres__id__in=genres)
+
+        if actors:
+            actors = self.params_to_ints(actors)
+            queryset = queryset.filter(actors__id__in=actors)
+
+        return queryset.distinct()
+
     def get_serializer_class(self):
         if self.action == "list":
             return MovieListSerializer
@@ -48,6 +86,30 @@ class MovieSessionViewSet(viewsets.ModelViewSet):
     queryset = MovieSession.objects.all()
     serializer_class = MovieSessionSerializer
 
+    def get_queryset(self):
+        queryset = self.queryset
+
+        if self.action == "list":
+            queryset = (
+                queryset
+                .annotate(
+                    tickets_available=(
+                        F("cinema_hall__rows") * F("cinema_hall__seats_in_row")
+                        - Count("tickets")
+                    )
+                )
+            ).order_by("show_time")
+
+        movie = self.request.query_params.get("movie")
+        date = self.request.query_params.get("date")
+
+        if movie:
+            queryset = queryset.filter(movie__id=int(movie))
+        if date:
+            queryset = queryset.filter(show_time__date=date)
+
+        return queryset.select_related("cinema_hall", "movie")
+
     def get_serializer_class(self):
         if self.action == "list":
             return MovieSessionListSerializer
@@ -56,3 +118,27 @@ def get_serializer_class(self):
             return MovieSessionDetailSerializer
 
         return MovieSessionSerializer
+
+
+class OrderViewSet(viewsets.ModelViewSet):
+    queryset = Order.objects
+    pagination_class = CustomPagination
+
+    def get_queryset(self):
+        queryset = Order.objects.prefetch_related(
+            "tickets__movie_session__movie",
+            "tickets__movie_session__cinema_hall"
+        ).filter(
+            user=self.request.user
+        )
+        return queryset
+
+    def perform_create(self, serializer):
+        serializer.save(user=self.request.user)
+
+    def get_serializer_class(self):
+        if self.action == "list":
+            return OrderListSerializer
+        if self.action == "retrieve":
+            return OrderDetailSerializer
+        return OrderSerializer

cinema_service/settings.py

@@ -124,7 +124,7 @@
 
 USE_I18N = True
 
-USE_TZ = False
+USE_TZ = True
 
 
 # Static files (CSS, JavaScript, Images)

cinema_service/urls.py

@@ -1,6 +1,7 @@
 from django.contrib import admin
 from django.urls import path, include
 
+
 urlpatterns = [
     path("admin/", admin.site.urls),
     path("api/cinema/", include("cinema.urls", namespace="cinema")),