From 6aa49605cc845eaeff6718538f22898aaecccaec Mon Sep 17 00:00:00 2001
From: Valentin Deniaud <vdeniaud@entrouvert.com>
Date: Thu, 4 Feb 2021 15:10:29 +0100
Subject: [PATCH] api: prefetch exceptions for recurring events (#50561)

---
 chrono/agendas/models.py |  3 ++-
 chrono/api/views.py      | 32 +++++++++++++++++++++++++++-----
 tests/test_api.py        |  2 +-
 3 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/chrono/agendas/models.py b/chrono/agendas/models.py
index ee16fa4a..147f0629 100644
--- a/chrono/agendas/models.py
+++ b/chrono/agendas/models.py
@@ -660,10 +660,11 @@ class Agenda(models.Model):
 
         if prefetched_queryset:
             recurring_events = self.prefetched_recurring_events
+            exceptions = self.prefetched_exceptions
         else:
             recurring_events = self.event_set.filter(recurrence_rule__isnull=False)
+            exceptions = self.get_recurrence_exceptions(min_start, max_start)
 
-        exceptions = self.get_recurrence_exceptions(min_start, max_start)
         for event in recurring_events:
             events.extend(
                 event.get_recurrences(
diff --git a/chrono/api/views.py b/chrono/api/views.py
index 6622d8c7..a5e5c948 100644
--- a/chrono/api/views.py
+++ b/chrono/api/views.py
@@ -565,6 +565,9 @@ class Agendas(APIView):
                 start_datetime__gte=localtime(now()),
             ).order_by()
             recurring_event_queryset = Event.objects.filter(recurrence_rule__isnull=False)
+            exceptions_desk = Desk.objects.filter(slug='_exceptions_holder').prefetch_related(
+                'unavailability_calendars'
+            )
             agendas_queryset = agendas_queryset.filter(kind='events').prefetch_related(
                 Prefetch(
                     'event_set',
@@ -576,15 +579,34 @@ class Agendas(APIView):
                     queryset=recurring_event_queryset,
                     to_attr='prefetched_recurring_events',
                 ),
+                Prefetch(
+                    'desk_set',
+                    queryset=exceptions_desk,
+                    to_attr='prefetched_desks',
+                ),
+            )
+            agendas_exceptions = TimePeriodException.objects.filter(
+                Q(desk__slug='_exceptions_holder', desk__agenda__in=agendas_queryset)
+                | Q(
+                    unavailability_calendar__desks__slug='_exceptions_holder',
+                    unavailability_calendar__desks__agenda__in=agendas_queryset,
+                ),
+                start_datetime__gte=localtime(now()),
             )
 
         agendas = []
         for agenda in agendas_queryset:
-            if with_open_events and not any(
-                not e.full for e in agenda.get_open_events(prefetched_queryset=True)
-            ):
-                # exclude agendas without open events
-                continue
+            if with_open_events:
+                desk = agenda.prefetched_desks[0]
+                uc_ids = [uc.pk for uc in desk.unavailability_calendars.all()]
+                agenda.prefetched_exceptions = [
+                    e
+                    for e in agendas_exceptions
+                    if e.desk_id == desk.pk or e.unavailability_calendar_id in uc_ids
+                ]
+                if not any(not e.full for e in agenda.get_open_events(prefetched_queryset=True)):
+                    # exclude agendas without open events
+                    continue
             agendas.append(get_agenda_detail(request, agenda))
 
         return Response({'data': agendas})
diff --git a/tests/test_api.py b/tests/test_api.py
index 17edca2d..361c6630 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -317,7 +317,7 @@ def test_agendas_api(app):
 
     with CaptureQueriesContext(connection) as ctx:
         resp = app.get('/api/agenda/', params={'with_open_events': '1'})
-        assert len(ctx.captured_queries) == 15
+        assert len(ctx.captured_queries) == 7
 
 
 def test_agendas_meetingtypes_api(app, some_data, meetings_agenda):