Add a method to refresh Product stock

src/modules/inventory/migrations/0001_initial.py

@@ -0,0 +1,23 @@
+# Generated by Django 3.1.14 on 2022-10-16 18:18
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Product',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('description', models.CharField(max_length=200)),
+                ('unit_price', models.FloatField()),
+                ('stock', models.IntegerField()),
+            ],
+        ),
+    ]

src/modules/inventory/models.py

@@ -2,4 +2,18 @@ from django.db import models
 
 
 class Product(models.Model):
-    pass
+    # https://git.disroot.org/nsukami/interview/src/branch/feat-1/src/modules/inventory/tests.py#L59
+    description = models.CharField(max_length=200)
+    unit_price = models.FloatField()
+    stock = models.IntegerField()
+
+    # https://git.disroot.org/nsukami/interview/src/branch/feat-1/src/modules/orders/tests.py#L111
+    # a product stock should be refreshed after an order is made
+    def refresh_from_db(self):
+        from modules.orders.models import OrderItem
+
+        # self.stock = self.stock - sum((oi.quantity for oi in self.orderitem_set.all()))
+        self.stock = self.stock - sum(
+            oi.quantity for oi in OrderItem.objects.filter(id=self.id)
+        )
+        self.save()

src/modules/inventory/views.py

@@ -1,3 +1,22 @@
-from django.shortcuts import render
+from rest_framework import serializers  # type:ignore
+from rest_framework import viewsets, mixins
+from .models import Product
 
-# Create your views here.
+
+class ProductSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Product
+        fields = "__all__"
+
+
+# https://git.disroot.org/nsukami/interview/src/branch/feat-1/src/modules/inventory/tests.py#L17
+# a product can be created, updated, listed but not deleted
+class ProductsViewSet(
+    mixins.CreateModelMixin,
+    mixins.ListModelMixin,
+    mixins.UpdateModelMixin,
+    mixins.RetrieveModelMixin,
+    viewsets.GenericViewSet,
+):
+    queryset = Product.objects.all()
+    serializer_class = ProductSerializer

src/modules/orders/migrations/0001_initial.py

@@ -0,0 +1,20 @@
+# Generated by Django 3.1.14 on 2022-10-16 18:18
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Order',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+            ],
+        ),
+    ]

src/modules/orders/models.py

@@ -2,4 +2,23 @@ from django.db import models
 
 
 class Order(models.Model):
-    pass
+    # https://git.disroot.org/nsukami/interview/src/branch/feat-1/src/modules/orders/tests.py#L55
+    @property
+    def total(self):
+        return sum([x.total for x in self.items.all()])
+
+
+class OrderItem(models.Model):
+    # https://git.disroot.org/nsukami/interview/src/branch/feat-1/src/modules/orders/tests.py#L55
+    order = models.ForeignKey(Order, related_name="items", on_delete=models.CASCADE)
+
+    # https://git.disroot.org/nsukami/interview/src/branch/feat-1/src/modules/orders/tests.py#L59
+    quantity = models.IntegerField(default=1)
+    description = models.CharField(max_length=255)
+    unit_price = models.FloatField()
+
+    # https://git.disroot.org/nsukami/interview/src/branch/feat-1/src/modules/orders/tests.py#L63
+    @property
+    def total(self):
+        # return self.product.unit_price * self.quantity
+        return int(self.unit_price * self.quantity)

src/modules/orders/views.py

@@ -1,3 +1,53 @@
-from django.shortcuts import render
-
 # Create your views here.
+from rest_framework import serializers  # type:ignore
+from rest_framework import viewsets, mixins
+from .models import Order, OrderItem
+from modules.inventory.models import Product
+from modules.inventory.views import ProductSerializer
+
+
+class ItemSerializer(serializers.ModelSerializer):
+    quantity = serializers.IntegerField(required=False)
+    unit_price = serializers.FloatField(required=False)
+    description = serializers.CharField(required=False)
+
+    class Meta:
+        model = OrderItem
+        fields = ["description", "quantity", "unit_price", "total"]
+
+
+class OrderSerializer(serializers.ModelSerializer):
+    items = ItemSerializer(many=True)
+
+    def create(self, validated_data):
+        order = Order.objects.create()
+        # I want to be able to access the id, the id represent the Product id
+        # So, I'm using initial_data instead of validated_data
+        # I'll need to find a proper way
+        for item_data in self.initial_data["items"]:
+            product = Product.objects.get(id=item_data["id"])
+            OrderItem.objects.create(
+                id=product.id,
+                order=order,
+                description=product.description,
+                unit_price=product.unit_price,
+                quantity=item_data["quantity"],
+            )
+        return order
+
+    class Meta:
+        model = Order
+        fields = ["id", "items", "total"]
+
+
+# https://git.disroot.org/nsukami/interview/src/branch/feat-1/src/modules/orders/tests.py#L189
+# an order can be listed, created, updated but not deleted
+class OrdersViewSet(
+    mixins.CreateModelMixin,
+    mixins.ListModelMixin,
+    mixins.RetrieveModelMixin,
+    viewsets.GenericViewSet,
+):
+
+    queryset = Order.objects.all()
+    serializer_class = OrderSerializer

src/pos/urls.py

@@ -13,9 +13,19 @@ Including another URLconf
     1. Import the include() function: from django.urls import include, path
     2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
 """
+
 from django.contrib import admin
-from django.urls import path
+from django.urls import path, include
+
+from rest_framework import routers
+from modules.inventory.views import ProductsViewSet
+from modules.orders.views import OrdersViewSet
+
+router = routers.DefaultRouter()
+router.register(r"products", ProductsViewSet)
+router.register(r"orders", OrdersViewSet)
 
 urlpatterns = [
-    path('admin/', admin.site.urls),
+    path("admin/", admin.site.urls),
+    path("api/", include(router.urls)),
 ]