Merge pull request #499 from ae-utbm/unify-account-creation

Unify account id creation

counter/models.py

@@ -21,6 +21,9 @@
 # Place - Suite 330, Boston, MA 02111-1307, USA.
 #
 #
+from __future__ import annotations
+
+from typing import Tuple
 
 from django.db import models
 from django.db.models.functions import Length
@@ -57,7 +60,7 @@ class Customer(models.Model):
 
     user = models.OneToOneField(User, primary_key=True, on_delete=models.CASCADE)
     account_id = models.CharField(_("account id"), max_length=10, unique=True)
-    amount = CurrencyField(_("amount"))
+    amount = CurrencyField(_("amount"), default=0)
     recorded_products = models.IntegerField(_("recorded product"), default=0)
 
     class Meta:
@@ -94,12 +97,27 @@ class Customer(models.Model):
         ) < timedelta(days=90)
 
     @classmethod
-    def new_for_user(cls, user: User):
+    def get_or_create(cls, user: User) -> Tuple[Customer, bool]:
         """
-        Create a new Customer instance for the user given in parameter without saving it
-        The account if is automatically generated and the amount set at 0
+        Work in pretty much the same way as the usual get_or_create method,
+        but with the default field replaced by some under the hood.
+
+        If the user has an account, return it as is.
+        Else create a new account with no money on it and a new unique account id
+
+        Example : ::
+
+            user = User.objects.get(pk=1)
+            account, created = Customer.get_or_create(user)
+            if created:
+                print(f"created a new account with id {account.id}")
+            else:
+                print(f"user has already an account, with {account.id} € on it"
         """
-        # account_id are number with a letter appended
+        if hasattr(user, "customer"):
+            return user.customer, False
+
+        # account_id are always a number with a letter appended
         account_id = (
             Customer.objects.order_by(Length("account_id"), "account_id")
             .values("account_id")
@@ -107,14 +125,19 @@ class Customer(models.Model):
         )
         if account_id is None:
             # legacy from the old site
-            return cls(user=user, account_id="1504a", amount=0)
-        account_id = account_id["account_id"]
-        num = int(account_id[:-1])
-        while Customer.objects.filter(account_id=account_id).exists():
-            num += 1
-            account_id = str(num) + random.choice(string.ascii_lowercase)
+            account = cls.objects.create(user=user, account_id="1504a")
+            return account, True
 
-        return cls(user=user, account_id=account_id, amount=0)
+        account_id = account_id["account_id"]
+        account_num = int(account_id[:-1])
+        while Customer.objects.filter(account_id=account_id).exists():
+            # when entering the first iteration, we are using an already existing account id
+            # so the loop should always execute at least one time
+            account_num += 1
+            account_id = f"{account_num}{random.choice(string.ascii_lowercase)}"
+
+        account = cls.objects.create(user=user, account_id=account_id)
+        return account, True
 
     def save(self, allow_negative=False, is_selling=False, *args, **kwargs):
         """