From 4f15b820a5d19174fd03a248a8429a5206427ff0 Mon Sep 17 00:00:00 2001
From: Ludovic Stephan <ludovic.stephan@ens.fr>
Date: Mon, 17 Jun 2019 21:36:09 +0200
Subject: [PATCH] Use manager from queryset

---
 bda/admin.py  |  2 +-
 bda/models.py | 12 +++++++-----
 bda/views.py  | 10 ++++++----
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/bda/admin.py b/bda/admin.py
index 18c712f8..7f626c7a 100644
--- a/bda/admin.py
+++ b/bda/admin.py
@@ -117,7 +117,7 @@ class ParticipantAdmin(ReadOnlyMixin, admin.ModelAdmin):
     inlines = [WithListingAttributionInline, WithoutListingAttributionInline]
 
     def get_queryset(self, request):
-        return self.model.objects_paid.get_queryset().annotate(
+        return self.model.objects.annotate_paid().annotate(
             nb_places=Count("attributions"),
             remain=Sum(
                 "attribution__spectacle__price", filter=Q(attribution__paid=False)
diff --git a/bda/models.py b/bda/models.py
index de87731e..cee2c3e1 100644
--- a/bda/models.py
+++ b/bda/models.py
@@ -170,17 +170,20 @@ class Attribution(models.Model):
         )
 
 
-class ParticipantPaidManager(models.Manager):
+class ParticipantPaidQueryset(models.QuerySet):
     """
         Un manager qui annote le queryset avec un champ `paid`,
         indiquant si un participant a payé toutes ses attributions.
     """
 
-    def get_queryset(self):
+    # OuterRef permet de se référer à un champ d'un modèle non encore fixé
+    # Voir:
+    # https://docs.djangoproject.com/en/2.2/ref/models/expressions/#django.db.models.OuterRef
+    def annotate_paid(self):
         unpaid = Attribution.objects.filter(
             participant=models.OuterRef("pk"), paid=False
         )
-        return super().get_queryset().annotate(paid=~Exists(unpaid))
+        return self.annotate(paid=~Exists(unpaid))
 
 
 class Participant(models.Model):
@@ -196,8 +199,7 @@ class Participant(models.Model):
         Spectacle, related_name="subscribed", blank=True
     )
 
-    objects = models.Manager()
-    objects_paid = ParticipantPaidManager()
+    objects = ParticipantPaidQueryset.as_manager()
 
     def __str__(self):
         return "%s - %s" % (self.user, self.tirage.title)
diff --git a/bda/views.py b/bda/views.py
index 40595cbf..6a0e7ec7 100644
--- a/bda/views.py
+++ b/bda/views.py
@@ -378,7 +378,7 @@ def revente_manage(request, tirage_id):
     - Annulation d'une revente après que le tirage a eu lieu
     """
     tirage = get_object_or_404(Tirage, id=tirage_id)
-    participant, created = Participant.objects_paid.get_or_create(
+    participant, created = Participant.annotate_paid().get_or_create(
         user=request.user, tirage=tirage
     )
 
@@ -734,9 +734,11 @@ class UnpaidParticipants(BuroRequiredMixin, ListView):
     template_name = "bda-unpaid.html"
 
     def get_queryset(self):
-        return Participant.objects_paid.filter(
-            tirage__id=self.kwargs["tirage_id"], paid=False
-        ).select_related("user")
+        return (
+            Participant.objects.annotate_paid()
+            .filter(tirage__id=self.kwargs["tirage_id"], paid=False)
+            .select_related("user")
+        )
 
 
 @buro_required