Rajoute un manager à Participant

On rajoute un manager qui annote les querysets avec si le participant a payé ou non

bda/models.py

@@ -9,7 +9,7 @@ from django.contrib.auth.models import User
 from django.contrib.sites.models import Site
 from django.core import mail
 from django.db import models
-from django.db.models import Count
+from django.db.models import Count, Exists
 from django.utils import formats, timezone
 
 
@@ -170,6 +170,19 @@ class Attribution(models.Model):
         )
 
 
+class ParticipantPaidManager(models.Manager):
+    """
+        Un manager qui annote le queryset avec un champ `paid`,
+        indiquant si un participant a payé toutes ses attributions.
+    """
+
+    def get_queryset(self):
+        unpaid = Attribution.objects.filter(
+            participant=models.OuterRef("pk"), paid=False
+        )
+        return super().get_queryset().annotate(paid=~Exists(unpaid))
+
+
 class Participant(models.Model):
     user = models.ForeignKey(User, on_delete=models.CASCADE)
     choices = models.ManyToManyField(
@@ -183,6 +196,9 @@ class Participant(models.Model):
         Spectacle, related_name="subscribed", blank=True
     )
 
+    objects = models.Manager()
+    objects_paid = ParticipantPaidManager()
+
     def __str__(self):
         return "%s - %s" % (self.user, self.tirage.title)