From 3fa1d5753ef030d6e89565bb4a05472863a49010 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timoth=C3=A9e=20Floure?= <timothee.floure@posteo.net>
Date: Wed, 15 Apr 2020 16:01:31 +0200
Subject: [PATCH] Minimal VAT validation on billing address registration

---
 uncloud_django_based/uncloud/requirements.txt |  4 ++++
 .../uncloud/uncloud_pay/serializers.py        |  7 +-----
 .../uncloud/uncloud_pay/views.py              | 24 +++++++++++++++++++
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/uncloud_django_based/uncloud/requirements.txt b/uncloud_django_based/uncloud/requirements.txt
index 90c9882..a7fc9f2 100644
--- a/uncloud_django_based/uncloud/requirements.txt
+++ b/uncloud_django_based/uncloud/requirements.txt
@@ -18,3 +18,7 @@ django-hardcopy
 # schema support
 pyyaml
 uritemplate
+
+# Comprehensive interface to validate VAT numbers, making use of the VIES
+# service for European countries.
+vat-validator
diff --git a/uncloud_django_based/uncloud/uncloud_pay/serializers.py b/uncloud_django_based/uncloud/uncloud_pay/serializers.py
index 664e19b..5579b14 100644
--- a/uncloud_django_based/uncloud/uncloud_pay/serializers.py
+++ b/uncloud_django_based/uncloud/uncloud_pay/serializers.py
@@ -56,15 +56,10 @@ class BillRecordSerializer(serializers.Serializer):
     order = serializers.HyperlinkedRelatedField(
             view_name='order-detail',
             read_only=True)
-    description = serializers.CharField()
-    recurring_period = serializers.CharField()
-    recurring_price = serializers.DecimalField(max_digits=10, decimal_places=2)
-    recurring_count = serializers.DecimalField(max_digits=10, decimal_places=2)
-    one_time_price = serializers.DecimalField(max_digits=10, decimal_places=2)
-    amount = serializers.DecimalField(max_digits=10, decimal_places=2)
 
 class BillSerializer(serializers.ModelSerializer):
     records = BillRecordSerializer(many=True, read_only=True)
+
     class Meta:
         model = Bill
         fields = ['reference', 'owner', 'total', 'due_date', 'creation_date',
diff --git a/uncloud_django_based/uncloud/uncloud_pay/views.py b/uncloud_django_based/uncloud/uncloud_pay/views.py
index 36a291a..5bd1ae6 100644
--- a/uncloud_django_based/uncloud/uncloud_pay/views.py
+++ b/uncloud_django_based/uncloud/uncloud_pay/views.py
@@ -7,12 +7,15 @@ from rest_framework.response import Response
 from rest_framework.decorators import action
 from rest_framework.reverse import reverse
 from rest_framework.decorators import renderer_classes
+from vat_validator import validate_vat, vies
+from vat_validator.countries import EU_COUNTRY_CODES
 
 import json
 
 from .models import *
 from .serializers import *
 from datetime import datetime
+from vat_validator import sanitize_vat
 import uncloud_pay.stripe as uncloud_stripe
 
 ###
@@ -206,7 +209,28 @@ class BillingAddressViewSet(mixins.CreateModelMixin,
     def create(self, request):
         serializer = self.get_serializer(data=request.data)
         serializer.is_valid(raise_exception=True)
+
+        # Validate VAT numbers.
+        country = serializer.validated_data["country"]
+        vat_number = serializer.validated_data["vat_number"]
+
+        # We ignore empty VAT numbers.
+        if vat_number != "":
+            if not validate_vat(country, vat_number):
+                return Response(
+                    {'error': 'Malformed VAT number.'},
+                    status=status.HTTP_400_BAD_REQUEST)
+            elif country in EU_COUNTRY_CODES:
+                # FIXME: make a synchroneous call to a third patry API here is
+                # not a good idea...
+                vies_state = vies.check_vat(country, vat_number)
+                if not vies_state.valid:
+                    return Response(
+                        {'error': 'European VAT number does not exist in VIES.'},
+                        status=status.HTTP_400_BAD_REQUEST)
+
         serializer.save(owner=request.user)
+        return Response(serializer.data)
 
 ###
 # Old admin stuff.