solution

cinema/migrations/0003_movie_duration.py

@@ -6,13 +6,13 @@
 class Migration(migrations.Migration):
 
     dependencies = [
-        ('cinema', '0002_initial'),
+        ("cinema", "0002_initial"),
     ]
 
     operations = [
         migrations.AddField(
-            model_name='movie',
-            name='duration',
+            model_name="movie",
+            name="duration",
             field=models.IntegerField(default=123),
             preserve_default=False,
         ),

cinema/migrations/0004_alter_genre_name.py

@@ -6,13 +6,13 @@
 class Migration(migrations.Migration):
 
     dependencies = [
-        ('cinema', '0003_movie_duration'),
+        ("cinema", "0003_movie_duration"),
     ]
 
     operations = [
         migrations.AlterField(
-            model_name='genre',
-            name='name',
+            model_name="genre",
+            name="name",
             field=models.CharField(max_length=255, unique=True),
         ),
     ]

cinema/models.py

@@ -63,9 +63,8 @@ def __str__(self):
 
 class Order(models.Model):
     created_at = models.DateTimeField(auto_now_add=True)
-    user = models.ForeignKey(
-        settings.AUTH_USER_MODEL, on_delete=models.CASCADE
-    )
+    user = models.ForeignKey(settings.AUTH_USER_MODEL,
+                             on_delete=models.CASCADE)
 
     def __str__(self):
         return str(self.created_at)
@@ -78,20 +77,19 @@ class Ticket(models.Model):
     movie_session = models.ForeignKey(
         MovieSession, on_delete=models.CASCADE, related_name="tickets"
     )
-    order = models.ForeignKey(
-        Order, on_delete=models.CASCADE, related_name="tickets"
-    )
+    order = models.ForeignKey(Order, on_delete=models.CASCADE,
+                              related_name="tickets")
     row = models.IntegerField()
     seat = models.IntegerField()
 
     def clean(self):
-        for ticket_attr_value, ticket_attr_name, cinema_hall_attr_name in [
+        for (ticket_attr_value, ticket_attr_name,
+             cinema_hall_attr_name) in [
             (self.row, "row", "rows"),
             (self.seat, "seat", "seats_in_row"),
         ]:
-            count_attrs = getattr(
-                self.movie_session.cinema_hall, cinema_hall_attr_name
-            )
+            count_attrs = getattr(self.movie_session.cinema_hall,
+                                  cinema_hall_attr_name)
             if not (1 <= ticket_attr_value <= count_attrs):
                 raise ValidationError(
                     {
@@ -110,14 +108,13 @@ def save(
         update_fields=None,
     ):
         self.full_clean()
-        super(Ticket, self).save(
-            force_insert, force_update, using, update_fields
-        )
+        super(Ticket, self).save(force_insert, force_update, using,
+                                 update_fields)
 
     def __str__(self):
-        return (
-            f"{str(self.movie_session)} (row: {self.row}, seat: {self.seat})"
-        )
+        return (f"{str(self.movie_session)} (row: {self.row}, seat: "
+                f"{self.seat})")
 
     class Meta:
         unique_together = ("movie_session", "row", "seat")
+        ordering = ("row",)

cinema/serializers.py

@@ -1,6 +1,14 @@
+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,
+                           Order,
+                           Ticket)
 
 
 class GenreSerializer(serializers.ModelSerializer):
@@ -28,9 +36,9 @@ class Meta:
 
 
 class MovieListSerializer(MovieSerializer):
-    genres = serializers.SlugRelatedField(
-        many=True, read_only=True, slug_field="name"
-    )
+    genres = serializers.SlugRelatedField(many=True,
+                                          read_only=True,
+                                          slug_field="name")
     actors = serializers.SlugRelatedField(
         many=True, read_only=True, slug_field="full_name"
     )
@@ -52,13 +60,14 @@ class Meta:
 
 
 class MovieSessionListSerializer(MovieSessionSerializer):
-    movie_title = serializers.CharField(source="movie.title", read_only=True)
-    cinema_hall_name = serializers.CharField(
-        source="cinema_hall.name", read_only=True
-    )
+    movie_title = serializers.CharField(source="movie.title",
+                                        read_only=True)
+    cinema_hall_name = serializers.CharField(source="cinema_hall.name",
+                                             read_only=True)
     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 +77,65 @@ class Meta:
             "movie_title",
             "cinema_hall_name",
             "cinema_hall_capacity",
+            "tickets_available",
+        )
+
+
+class TicketDetailSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Ticket
+        fields = (
+            "row",
+            "seat",
         )
 
 
 class MovieSessionDetailSerializer(MovieSessionSerializer):
     movie = MovieListSerializer(many=False, read_only=True)
     cinema_hall = CinemaHallSerializer(many=False, read_only=True)
+    taken_places = TicketDetailSerializer(many=True, source="tickets",
+                                          read_only=True)
 
     class Meta:
         model = MovieSession
-        fields = ("id", "show_time", "movie", "cinema_hall")
+        fields = ("id", "show_time", "movie", "cinema_hall", "taken_places")
+
+
+class TicketSerializer(serializers.ModelSerializer):
+    movie_session = MovieSessionListSerializer(read_only=True)
+
+    class Meta:
+        model = Ticket
+        fields = (
+            "id",
+            "row",
+            "seat",
+            "movie_session",
+        )
+        validators = [
+            UniqueTogetherValidator(
+                queryset=Ticket.objects.all(), fields=("row",
+                                                       "seat",
+                                                       "movie_session")
+            )
+        ]
+
+
+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

cinema/tests/test_actor_api.py

@@ -16,9 +16,7 @@ def test_get_actors(self):
         response = self.client.get("/api/cinema/actors/")
         self.assertEqual(response.status_code, status.HTTP_200_OK)
         actors_full_names = [actor["full_name"] for actor in response.data]
-        self.assertEqual(
-            sorted(actors_full_names), ["George Clooney", "Keanu Reeves"]
-        )
+        self.assertEqual(sorted(actors_full_names), ["George Clooney", "Keanu Reeves"])
 
     def test_post_actors(self):
         response = self.client.post(

cinema/tests/test_cinema_hall_api.py

@@ -31,9 +31,7 @@ def test_get_cinema_halls(self):
         self.assertEqual(response.status_code, status.HTTP_200_OK)
         self.assertEqual(response.data[0]["name"], blue_hall["name"])
         self.assertEqual(response.data[0]["rows"], blue_hall["rows"])
-        self.assertEqual(
-            response.data[0]["seats_in_row"], blue_hall["seats_in_row"]
-        )
+        self.assertEqual(response.data[0]["seats_in_row"], blue_hall["seats_in_row"])
         vip_hall = {
             "name": "VIP",
             "rows": 6,
@@ -43,9 +41,7 @@ def test_get_cinema_halls(self):
         self.assertEqual(response.status_code, status.HTTP_200_OK)
         self.assertEqual(response.data[1]["name"], vip_hall["name"])
         self.assertEqual(response.data[1]["rows"], vip_hall["rows"])
-        self.assertEqual(
-            response.data[1]["seats_in_row"], vip_hall["seats_in_row"]
-        )
+        self.assertEqual(response.data[1]["seats_in_row"], vip_hall["seats_in_row"])
 
     def test_post_cinema_halls(self):
         response = self.client.post(
@@ -72,9 +68,7 @@ def test_get_cinema_hall(self):
         self.assertEqual(response.status_code, status.HTTP_200_OK)
         self.assertEqual(response.data["name"], vip_hall["name"])
         self.assertEqual(response.data["rows"], vip_hall["rows"])
-        self.assertEqual(
-            response.data["seats_in_row"], vip_hall["seats_in_row"]
-        )
+        self.assertEqual(response.data["seats_in_row"], vip_hall["seats_in_row"])
         self.assertEqual(response.data["capacity"], vip_hall["capacity"])
 
     def test_get_invalid_cinema_hall(self):

cinema/tests/test_movie_api.py

@@ -15,9 +15,7 @@ def setUp(self):
         self.comedy = Genre.objects.create(
             name="Comedy",
         )
-        self.actress = Actor.objects.create(
-            first_name="Kate", last_name="Winslet"
-        )
+        self.actress = Actor.objects.create(first_name="Kate", last_name="Winslet")
         self.movie = Movie.objects.create(
             title="Titanic",
             description="Titanic description",
@@ -42,21 +40,15 @@ def test_get_movies(self):
             self.assertEqual(movies.data[0][field], titanic[field])
 
     def test_get_movies_with_genres_filtering(self):
-        movies = self.client.get(
-            f"/api/cinema/movies/?genres={self.comedy.id}"
-        )
+        movies = self.client.get(f"/api/cinema/movies/?genres={self.comedy.id}")
         self.assertEqual(len(movies.data), 1)
-        movies = self.client.get(
-            f"/api/cinema/movies/?genres={self.comedy.id},2,3"
-        )
+        movies = self.client.get(f"/api/cinema/movies/?genres={self.comedy.id},2,3")
         self.assertEqual(len(movies.data), 1)
         movies = self.client.get("/api/cinema/movies/?genres=123213")
         self.assertEqual(len(movies.data), 0)
 
     def test_get_movies_with_actors_filtering(self):
-        movies = self.client.get(
-            f"/api/cinema/movies/?actors={self.actress.id}"
-        )
+        movies = self.client.get(f"/api/cinema/movies/?actors={self.actress.id}")
         self.assertEqual(len(movies.data), 1)
         movies = self.client.get(f"/api/cinema/movies/?actors={123}")
         self.assertEqual(len(movies.data), 0)
@@ -111,9 +103,7 @@ def test_get_movie(self):
         self.assertEqual(response.data["genres"][1]["name"], "Comedy")
         self.assertEqual(response.data["actors"][0]["first_name"], "Kate")
         self.assertEqual(response.data["actors"][0]["last_name"], "Winslet")
-        self.assertEqual(
-            response.data["actors"][0]["full_name"], "Kate Winslet"
-        )
+        self.assertEqual(response.data["actors"][0]["full_name"], "Kate Winslet")
 
     def test_get_invalid_movie(self):
         response = self.client.get("/api/cinema/movies/100/")

cinema/tests/test_movie_session_api.py

@@ -34,12 +34,7 @@ def setUp(self):
         self.movie_session = MovieSession.objects.create(
             movie=self.movie,
             cinema_hall=self.cinema_hall,
-            show_time=datetime.datetime(
-                year=2022,
-                month=9,
-                day=2,
-                hour=9
-            ),
+            show_time=datetime.datetime(year=2022, month=9, day=2, hour=9),
         )
 
     def test_get_movie_sessions(self):
@@ -51,20 +46,14 @@ def test_get_movie_sessions(self):
         }
         self.assertEqual(movie_sessions.status_code, status.HTTP_200_OK)
         for field in movie_session:
-            self.assertEqual(
-                movie_sessions.data[0][field], movie_session[field]
-            )
+            self.assertEqual(movie_sessions.data[0][field], movie_session[field])
 
     def test_get_movie_sessions_filtered_by_date(self):
-        movie_sessions = self.client.get(
-            "/api/cinema/movie_sessions/?date=2022-09-02"
-        )
+        movie_sessions = self.client.get("/api/cinema/movie_sessions/?date=2022-09-02")
         self.assertEqual(movie_sessions.status_code, status.HTTP_200_OK)
         self.assertEqual(len(movie_sessions.data), 1)
 
-        movie_sessions = self.client.get(
-            "/api/cinema/movie_sessions/?date=2022-09-01"
-        )
+        movie_sessions = self.client.get("/api/cinema/movie_sessions/?date=2022-09-01")
         self.assertEqual(movie_sessions.status_code, status.HTTP_200_OK)
         self.assertEqual(len(movie_sessions.data), 0)
 
@@ -75,9 +64,7 @@ def test_get_movie_sessions_filtered_by_movie(self):
         self.assertEqual(movie_sessions.status_code, status.HTTP_200_OK)
         self.assertEqual(len(movie_sessions.data), 1)
 
-        movie_sessions = self.client.get(
-            "/api/cinema/movie_sessions/?movie=1234"
-        )
+        movie_sessions = self.client.get("/api/cinema/movie_sessions/?movie=1234")
         self.assertEqual(movie_sessions.status_code, status.HTTP_200_OK)
         self.assertEqual(len(movie_sessions.data), 0)
 
@@ -117,9 +104,7 @@ def test_get_movie_session(self):
         response = self.client.get("/api/cinema/movie_sessions/1/")
         self.assertEqual(response.status_code, status.HTTP_200_OK)
         self.assertEqual(response.data["movie"]["title"], "Titanic")
-        self.assertEqual(
-            response.data["movie"]["description"], "Titanic description"
-        )
+        self.assertEqual(response.data["movie"]["description"], "Titanic description")
         self.assertEqual(response.data["movie"]["duration"], 123)
         self.assertEqual(response.data["movie"]["genres"], ["Drama", "Comedy"])
         self.assertEqual(response.data["movie"]["actors"], ["Kate Winslet"])

cinema/tests/test_order_api.py

@@ -26,9 +26,7 @@ def setUp(self):
         self.comedy = Genre.objects.create(
             name="Comedy",
         )
-        self.actress = Actor.objects.create(
-            first_name="Kate", last_name="Winslet"
-        )
+        self.actress = Actor.objects.create(first_name="Kate", last_name="Winslet")
         self.movie = Movie.objects.create(
             title="Titanic",
             description="Titanic description",
@@ -73,12 +71,8 @@ def test_movie_session_detail_tickets(self):
             f"/api/cinema/movie_sessions/{self.movie_session.id}/"
         )
         self.assertEqual(response.status_code, status.HTTP_200_OK)
-        self.assertEqual(
-            response.data["taken_places"][0]["row"], self.ticket.row
-        )
-        self.assertEqual(
-            response.data["taken_places"][0]["seat"], self.ticket.seat
-        )
+        self.assertEqual(response.data["taken_places"][0]["row"], self.ticket.row)
+        self.assertEqual(response.data["taken_places"][0]["seat"], self.ticket.seat)
 
     def test_movie_session_list_tickets_available(self):
         response = self.client.get(f"/api/cinema/movie_sessions/")