[credit card] implement payment

uncloud_pay/models.py

@@ -64,8 +64,8 @@ class Currency(models.TextChoices):
     Possible currencies to be billed
     """
     CHF   = 'CHF', _('Swiss Franc')
-    EUR   = 'EUR', _('Euro')
-    USD   = 'USD', _('US Dollar')
+#    EUR   = 'EUR', _('Euro')
+#    USD   = 'USD', _('US Dollar')
 
 
 def get_balance_for_user(user):
@@ -93,28 +93,30 @@ class StripeCustomer(models.Model):
 
 
 class StripeCreditCard(models.Model):
-    owner = models.OneToOneField( get_user_model(),
-            on_delete=models.CASCADE)
+    owner = models.ForeignKey(get_user_model(), on_delete=models.CASCADE)
 
     card_name = models.CharField(null=False, max_length=128, default="My credit card")
     card_id = models.CharField(null=False, max_length=32)
     last4 = models.CharField(null=False, max_length=4)
     brand = models.CharField(null=False, max_length=64)
     expiry_date = models.DateField(null=False)
+    active = models.BooleanField(default=False)
+
+    class Meta:
+        constraints = [
+            models.UniqueConstraint(fields=['owner'],
+                                    condition=Q(active=True),
+                                    name='one_active_card_per_user')
+        ]
+
 
     def __str__(self):
         return f"{self.card_name}: {self.brand} {self.last4} ({self.expiry_date})"
 
-
-###
-# Payments and Payment Methods.
-
 class Payment(models.Model):
-    owner = models.ForeignKey(get_user_model(),
-            on_delete=models.CASCADE)
+    owner = models.ForeignKey(get_user_model(), on_delete=models.CASCADE)
 
     amount = models.DecimalField(
-            default=0.0,
             max_digits=AMOUNT_MAX_DIGITS,
             decimal_places=AMOUNT_DECIMALS,
             validators=[MinValueValidator(0)])
@@ -128,21 +130,18 @@ class Payment(models.Model):
                                   ('unknown', 'Unknown')
                               ),
                               default='unknown')
-    timestamp = models.DateTimeField(editable=False, auto_now_add=True)
 
-    # We override save() in order to active products awaiting payment.
-    def save(self, *args, **kwargs):
-        # _state.adding is switched to false after super(...) call.
-        being_created = self._state.adding
+    timestamp = models.DateTimeField(default=timezone.now)
 
-        unpaid_bills_before_payment = Bill.get_unpaid_for(self.owner)
-        super(Payment, self).save(*args, **kwargs) # Save payment in DB.
-        unpaid_bills_after_payment = Bill.get_unpaid_for(self.owner)
+    currency = models.CharField(max_length=32, choices=Currency.choices, default=Currency.CHF)
 
-        newly_paid_bills = list(
-                set(unpaid_bills_before_payment) - set(unpaid_bills_after_payment))
-        for bill in newly_paid_bills:
-            bill.activate_products()
+    external_reference = models.CharField(max_length=256, default="", null=True, blank=True)
+
+    def __str__(self):
+        return f"{self.amount}{self.currency} from {self.owner} via {self.source} on {self.timestamp}"
+
+###
+# Payments and Payment Methods.
 
 
 class PaymentMethod(models.Model):