From 35d8fec2a38c59675c71e11aec55636bb58d05c9 Mon Sep 17 00:00:00 2001
From: Adam Goldsmith <adam@adamgoldsmith.name>
Date: Wed, 3 Jan 2024 14:25:04 -0500
Subject: [PATCH] membershipworks: Use GeneratedField for
 EventMeetingTime.duration

Relevant Django bug was fixed in 5.0.1
https://code.djangoproject.com/ticket/35019
---
 .../0007_eventmeetingtime_duration.py         | 24 +++++++++++++++
 membershipworks/models.py                     | 29 ++++---------------
 2 files changed, 30 insertions(+), 23 deletions(-)
 create mode 100644 membershipworks/migrations/0007_eventmeetingtime_duration.py

diff --git a/membershipworks/migrations/0007_eventmeetingtime_duration.py b/membershipworks/migrations/0007_eventmeetingtime_duration.py
new file mode 100644
index 0000000..59289af
--- /dev/null
+++ b/membershipworks/migrations/0007_eventmeetingtime_duration.py
@@ -0,0 +1,24 @@
+# Generated by Django 5.0.1 on 2024-01-03 19:22
+
+import django.db.models.expressions
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("membershipworks", "0006_eventext_instructor_flat_rate_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="eventmeetingtime",
+            name="duration",
+            field=models.GeneratedField(
+                db_persist=False,
+                expression=django.db.models.expressions.CombinedExpression(
+                    models.F("end"), "-", models.F("start")
+                ),
+                output_field=models.DurationField(),
+            ),
+        ),
+    ]
diff --git a/membershipworks/models.py b/membershipworks/models.py
index caf7acb..94a54c5 100644
--- a/membershipworks/models.py
+++ b/membershipworks/models.py
@@ -415,13 +415,7 @@ class EventInstructor(models.Model):
 
 class EventExtManager(models.Manager["EventExt"]):
     def get_queryset(self) -> models.QuerySet["EventExt"]:
-        return (
-            super()
-            .get_queryset()
-            .annotate(duration=Sum(F("meeting_times__end") - F("meeting_times__start")))
-        )
-        # TODO: use simpler expression when GeneratedField fixed
-        # return super().get_queryset().annotate(duration=Sum("meeting_times__duration"))
+        return super().get_queryset().annotate(duration=Sum("meeting_times__duration"))
 
 
 class EventExt(Event):
@@ -446,29 +440,18 @@ class EventExt(Event):
         verbose_name = "event"
 
 
-class EventMeetingTimeManager(models.Manager["EventMeetingTime"]):
-    def get_queryset(self) -> models.QuerySet["EventMeetingTime"]:
-        return super().get_queryset().annotate(duration=F("end") - F("start"))
-
-
 class EventMeetingTime(models.Model):
-    objects = EventMeetingTimeManager()
-
     event = models.ForeignKey(
         EventExt, on_delete=models.CASCADE, related_name="meeting_times"
     )
     start = models.DateTimeField()
     end = models.DateTimeField()
 
-    # TODO: Should use generated field instead of manager, but this is
-    # broken due to current Django bug, pending next release (> 5.0)
-    # ref: https://code.djangoproject.com/ticket/35019
-
-    # duration = models.GeneratedField(
-    #     expression=F("end") - F("start"),
-    #     output_field=models.DurationField(),
-    #     db_persist=False,
-    # )
+    duration = models.GeneratedField(
+        expression=F("end") - F("start"),
+        output_field=models.DurationField(),
+        db_persist=False,
+    )
 
     class Meta:
         constraints = [