'Solution'

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,
+    Order,
+    Ticket
+)
 
 
 class GenreSerializer(serializers.ModelSerializer):
@@ -68,6 +77,7 @@ class Meta:
             "movie_title",
             "cinema_hall_name",
             "cinema_hall_capacity",
+            "tickets_available",
         )
 
 
@@ -77,4 +87,52 @@ class MovieSessionDetailSerializer(MovieSessionSerializer):
 
     class Meta:
         model = MovieSession
-        fields = ("id", "show_time", "movie", "cinema_hall")
+        fields = ("id", "show_time", "movie", "cinema_hall", "taken_places")
+
+
+class TicketSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Ticket
+        fields = ("id", "row", "seat", "movie_session")
+
+
+class TicketRetrieveSerializer(serializers.ModelSerializer):
+    movie_session = MovieSessionListSerializer(many=False)
+
+    class Meta:
+        model = Ticket
+        fields = [
+            "id",
+            "order",
+            "row",
+            "seat",
+            "movie_session"
+        ]
+
+
+class OrderSerializer(serializers.ModelSerializer):
+    tickets = TicketRetrieveSerializer(
+        many=True,
+        read_only=False,
+        allow_empty=False
+    )
+
+    class Meta:
+        model = Order
+        fields = [
+            "id",
+            "created_at",
+            "tickets"
+        ]
+
+    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 = TicketRetrieveSerializer(many=True, read_only=True)

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 +1,7 @@
 from rest_framework import viewsets
+from rest_framework.pagination import PageNumberPagination
 
-from cinema.models import Genre, Actor, CinemaHall, Movie, MovieSession
+from cinema.models import Genre, Actor, CinemaHall, Movie, MovieSession, Order
 
 from cinema.serializers import (
     GenreSerializer,
@@ -12,6 +13,8 @@
     MovieDetailSerializer,
     MovieSessionDetailSerializer,
     MovieListSerializer,
+    OrderSerializer,
+    OrderListSerializer
 )
 
 
@@ -56,3 +59,30 @@ def get_serializer_class(self):
             return MovieSessionDetailSerializer
 
         return MovieSessionSerializer
+
+
+class OrderSetPagination(PageNumberPagination):
+    page_size = 1
+    page_size_query_param = "page_size"
+    max_page_size = 3
+
+
+class OrderViewSet(viewsets.ModelViewSet):
+    queryset = Order.objects.all()
+    serializer_class = OrderSerializer
+    pagination_class = OrderSetPagination
+
+    def get_queryset(self):
+        queryset = self.queryset.filter(user=self.request.user)
+        if self.action == "list":
+            queryset = queryset.prefetch_related("tickets__movie_session")
+        return queryset
+
+    def perform_create(self, serializer):
+        serializer.save(user=self.request.user)
+
+    def get_serializer_class(self):
+        serializer = self.serializer_class
+        if self.action == "list":
+            serializer = OrderListSerializer
+        return serializer