Solution

.flake8

@@ -1,6 +1,6 @@
 [flake8]
 inline-quotes = "
-ignore = E203, E266, W503, N807, N818, F401
+ignore = E203, E266, W503, N807, N818, F401, E126
 max-line-length = 79
 max-complexity = 18
 select = B,C,E,F,W,T4,B9,Q0,N8,VNE

.gitignore

@@ -7,4 +7,5 @@ venv/
 .pytest_cache/
 **__pycache__/
 *.pyc
-app/db.sqlite3
+app/db.sqlite3
+db.sqlite3

cinema/serializers.py

@@ -1,6 +1,16 @@
+from django.db import transaction
 from rest_framework import serializers
+from rest_framework.validators import UniqueTogetherValidator
 
-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 +69,7 @@ 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 +79,81 @@ class Meta:
             "movie_title",
             "cinema_hall_name",
             "cinema_hall_capacity",
+            "tickets_available",
         )
 
 
+class TicketSerializer(serializers.ModelSerializer):
+    movie_session = MovieSessionSerializer()
+
+    class Meta:
+        model = Ticket
+        fields = ("id", "movie_session", "row", "seat")
+
+    def validate(self, attrs):
+        movie_session = attrs.get("movie_session")
+        row = attrs.get("row")
+        seat = attrs.get("seat")
+        cinema_hall = movie_session.cinema_hall
+
+        for ticket_attr_value, ticket_attr_name, cinema_hall_attr_name in [
+            (row, "row", "rows"),
+            (seat, "seat", "seats_in_row"),
+        ]:
+            count_attrs = getattr(cinema_hall, cinema_hall_attr_name)
+            if not (1 <= ticket_attr_value <= count_attrs):
+                raise serializers.ValidationError(
+                    {
+                        ticket_attr_name: f"{ticket_attr_name} "
+                        f"number must be in available range: "
+                        f"(1, {cinema_hall_attr_name}): "
+                        f"(1, {count_attrs})"
+                    }
+                )
+        return attrs
+
+
 class MovieSessionDetailSerializer(MovieSessionSerializer):
     movie = MovieListSerializer(many=False, read_only=True)
     cinema_hall = CinemaHallSerializer(many=False, read_only=True)
+    taken_places = serializers.SerializerMethodField()
 
     class Meta:
         model = MovieSession
-        fields = ("id", "show_time", "movie", "cinema_hall")
+        fields = ("id", "show_time", "movie", "cinema_hall", "taken_places")
+
+    def get_taken_places(self, obj):
+        return [
+            {"row": ticket.row, "seat": ticket.seat}
+            for ticket in obj.tickets.all()
+        ]
+
+
+class OrderSerializer(serializers.ModelSerializer):
+    tickets = TicketSerializer(many=True, read_only=False, allow_empty=False)
+
+    class Meta:
+        model = Order
+        fields = ("id", "created_at", "tickets")
+        validators = [
+            UniqueTogetherValidator(
+                queryset=Ticket.objects.all(),
+                fields=["movie_session", "row", "seat"]
+            )
+        ]
+
+    def create(self, validated_data):
+        with transaction.atomic():
+            tickets_date = validated_data.pop("tickets")
+            order = Order.objects.create(**validated_data)
+            for ticket_data in tickets_date:
+                Ticket.objects.create(order=order, **ticket_data)
+            return order
+
+
+class TicketListSerializer(TicketSerializer):
+    movie_session = MovieSessionListSerializer(read_only=True)
+
+
+class OrderListSerializer(OrderSerializer):
+    tickets = TicketListSerializer(read_only=True, many=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 +1,17 @@
+from django.db.models import Count, F
+from django.utils.dateparse import parse_date
 from rest_framework import viewsets
+from rest_framework.pagination import PageNumberPagination
+
+from cinema.models import (
+    Genre,
+    Actor,
+    CinemaHall,
+    Movie,
+    MovieSession,
+    Order
+)
 
-from cinema.models import Genre, Actor, CinemaHall, Movie, MovieSession
 
 from cinema.serializers import (
     GenreSerializer,
@@ -11,7 +22,7 @@
     MovieSessionListSerializer,
     MovieDetailSerializer,
     MovieSessionDetailSerializer,
-    MovieListSerializer,
+    MovieListSerializer, OrderSerializer, OrderListSerializer,
 )
 
 
@@ -34,6 +45,10 @@ class MovieViewSet(viewsets.ModelViewSet):
     queryset = Movie.objects.all()
     serializer_class = MovieSerializer
 
+    @staticmethod
+    def _params_to_ints(query_string):
+        return [int(str_id) for str_id in query_string.split(",")]
+
     def get_serializer_class(self):
         if self.action == "list":
             return MovieListSerializer
@@ -43,6 +58,28 @@ def get_serializer_class(self):
 
         return MovieSerializer
 
+    def get_queryset(self):
+        queryset = self.queryset
+
+        actors = self.request.query_params.get("actors")
+        if actors:
+            actors = self._params_to_ints(actors)
+            queryset = queryset.filter(actors__id__in=actors)
+
+        genres = self.request.query_params.get("genres")
+        if genres:
+            genres = self._params_to_ints(genres)
+            queryset = queryset.filter(genres__id__in=genres)
+
+        title = self.request.query_params.get("title")
+        if title:
+            queryset = queryset.filter(title__icontains=title)
+
+        if self.action in ("list", "retrieve"):
+            return queryset.prefetch_related("actors", "genres")
+
+        return queryset.distinct()
+
 
 class MovieSessionViewSet(viewsets.ModelViewSet):
     queryset = MovieSession.objects.all()
@@ -56,3 +93,66 @@ def get_serializer_class(self):
             return MovieSessionDetailSerializer
 
         return MovieSessionSerializer
+
+    def get_queryset(self):
+        queryset = self.queryset
+        date = self.request.query_params.get("date")
+        movie = self.request.query_params.get("movie")
+
+        if date:
+            date = parse_date(date)
+            if date:
+                queryset = queryset.filter(show_time__date=date)
+
+        if movie:
+            queryset = queryset.filter(movie_id=movie)
+
+        if self.action in "list":
+            return (
+                queryset
+                .select_related()
+                .annotate(
+                    tickets_available=(
+                            F("cinema_hall__rows")
+                            * F("cinema_hall__seats_in_row")
+                            - Count("tickets")
+                    )
+                )
+            )
+        elif self.action in "retrieve":
+            return queryset.select_related()
+        return queryset.distinct()
+
+
+class OrderSetPagination(PageNumberPagination):
+    page_size = 2
+    page_size_query_param = "page_size"
+    max_page_size = 10
+
+
+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__movie",
+                "tickets__movie_session__cinema_hall"
+            )
+
+        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

cinema_service/settings.py

@@ -124,7 +124,7 @@
 
 USE_I18N = True
 
-USE_TZ = False
+USE_TZ = True
 
 
 # Static files (CSS, JavaScript, Images)
@@ -136,3 +136,9 @@
 # https://docs.djangoproject.com/en/4.0/ref/settings/#default-auto-field
 
 DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"
+
+# REST_FRAMEWORK = {
+#     "DEFAULT_PAGINATION_CLASS":
+#         "rest_framework.pagination.LimitOffsetPagination",
+#     "PAGE_SIZE": 2
+# }