[DTOSS-9252] Extract status into an append only table

README.md

@@ -78,7 +78,7 @@ Database migrations are handled by [Django's database migration functionality](h
 - `poetry run manage.py migrate` loads database migrations
 - `poetry run manage.py makemigrations` generates new database migrations
 
-Note the database migration runs in the deployment pipeline *after* the application deployment. The deployed code must be compatible with the schema before AND after the schema changes. This also removes potential errors when using a rolling app deployment as multiple app versions may access the database at the same time. To enforce it, make sure to always separate code changes and database migrations into different pull requests.
+Note the database migration runs in the deployment pipeline _after_ the application deployment. The deployed code must be compatible with the schema before AND after the schema changes. This also removes potential errors when using a rolling app deployment as multiple app versions may access the database at the same time. To enforce it, make sure to always separate code changes and database migrations into different pull requests.
 
 ### Django admin
 

manage_breast_screening/assets/sass/main.scss

@@ -44,4 +44,4 @@ a[href="#"] {
   top: 10px;
   right: 0;
   text-align: right;
-}
+}

manage_breast_screening/clinics/fixtures/clinics.json

@@ -28,8 +28,7 @@
       "starts_at": "2025-04-01T09:00:00Z",
       "ends_at": "2025-04-04T17:00:00Z",
       "type": "SCREENING",
-      "risk_type": "ROUTINE_RISK",
-      "state": "IN_PROGRESS"
+      "risk_type": "ROUTINE_RISK"
     }
   },
   {
@@ -86,5 +85,14 @@
       "starts_at": "2025-05-01T13:00:00Z",
       "duration_in_minutes": 30
     }
+  },
+  {
+    "model": "clinics.clinicstatus",
+    "pk": "82da38f1-f39f-4692-8a76-d621630caa69",
+    "fields": {
+      "created_at": "2025-06-20T09:22:36.070Z",
+      "state": "IN_PROGRESS",
+      "clinic": "ce662c8b-92dc-4c82-9d5d-1ddcb201e2b6"
+    }
   }
 ]

manage_breast_screening/clinics/migrations/0013_move_clinic_state_to_table.py

@@ -0,0 +1,86 @@
+# Generated by Django 5.2.3 on 2025-06-17 12:51
+
+import uuid
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+def extract_status(apps, schema_editor):
+    Clinic = apps.get_model("clinics", "Clinic")
+    for clinic in Clinic.objects.all():
+        clinic.statuses.create(state=clinic.state)
+
+
+def revert_extract_status(apps, schema_editor):
+    Clinic = apps.get_model("clinics", "Clinic")
+    for clinic in Clinic.objects.all():
+        clinic.state = clinic.statuses.first().state
+        clinic.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("clinics", "0012_remove_screeningepisode_participant_and_more"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="clinic",
+            name="state",
+            field=models.CharField(
+                choices=[
+                    ("SCHEDULED", "Scheduled"),
+                    ("IN_PROGRESS", "In progress"),
+                    ("CLOSED", "Closed"),
+                    ("CANCELLED", "Cancelled"),
+                ],
+                max_length=50,
+                null=True,
+            ),
+        ),
+        migrations.CreateModel(
+            name="ClinicStatus",
+            fields=[
+                (
+                    "id",
+                    models.UUIDField(
+                        default=uuid.uuid4,
+                        editable=False,
+                        primary_key=True,
+                        serialize=False,
+                    ),
+                ),
+                ("created_at", models.DateTimeField(auto_now_add=True)),
+                (
+                    "state",
+                    models.CharField(
+                        choices=[
+                            ("SCHEDULED", "Scheduled"),
+                            ("IN_PROGRESS", "In progress"),
+                            ("CLOSED", "Closed"),
+                            ("CANCELLED", "Cancelled"),
+                        ],
+                        max_length=50,
+                    ),
+                ),
+                (
+                    "clinic",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.PROTECT,
+                        related_name="statuses",
+                        to="clinics.clinic",
+                    ),
+                ),
+            ],
+            options={
+                "ordering": ["-created_at"],
+            },
+        ),
+        migrations.RunPython(extract_status, revert_extract_status),
+        migrations.RemoveField(
+            model_name="clinic",
+            name="state",
+        ),
+    ]

manage_breast_screening/clinics/migrations/0014_merge_20250620_1113.py

@@ -0,0 +1,14 @@
+# Generated by Django 5.2.3 on 2025-06-20 11:13
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('clinics', '0013_alter_clinic_setting_alter_clinicslot_clinic_and_more'),
+        ('clinics', '0013_move_clinic_state_to_table'),
+    ]
+
+    operations = [
+    ]

manage_breast_screening/clinics/models.py

@@ -1,3 +1,4 @@
+import uuid
 from datetime import date
 from enum import StrEnum
 
@@ -61,14 +62,11 @@ def completed(self):
         """
         return self.filter(starts_at__date__lt=date.today())
 
+    def with_statuses(self):
+        return self.prefetch_related("statuses")
 
-class Clinic(BaseModel):
-    class State:
-        SCHEDULED = "SCHEDULED"
-        IN_PROGRESS = "IN_PROGRESS"
-        CLOSED = "CLOSED"
-        CANCELLED = "CANCELLED"
 
+class Clinic(BaseModel):
     class RiskType:
         MIXED_RISK = "MIXED_RISK"
         ROUTINE_RISK = "ROUTINE_RISK"
@@ -83,13 +81,6 @@ class TimeOfDay:
         MORNING = "morning"
         AFTERNOON = "afternoon"
 
-    STATE_CHOICES = {
-        State.SCHEDULED: "Scheduled",
-        State.IN_PROGRESS: "In progress",
-        State.CLOSED: "Closed",
-        State.CANCELLED: "Cancelled",
-    }
-
     RISK_TYPE_CHOICES = {
         RiskType.MIXED_RISK: "Mixed risk",
         RiskType.ROUTINE_RISK: "Routine risk",
@@ -103,10 +94,12 @@ class TimeOfDay:
     ends_at = models.DateTimeField()
     type = models.CharField(choices=TYPE_CHOICES, max_length=50)
     risk_type = models.CharField(choices=RISK_TYPE_CHOICES, max_length=50)
-    state = models.CharField(choices=STATE_CHOICES, max_length=50)
 
     objects = ClinicQuerySet.as_manager()
 
+    def current_status(self):
+        return self.statuses.first()
+
     def session_type(self):
         start_hour = self.starts_at.hour
         duration = (self.ends_at - self.starts_at).seconds
@@ -137,3 +130,27 @@ class ClinicSlot(BaseModel):
     )
     starts_at = models.DateTimeField()
     duration_in_minutes = models.IntegerField()
+
+
+class ClinicStatus(models.Model):
+    SCHEDULED = "SCHEDULED"
+    IN_PROGRESS = "IN_PROGRESS"
+    CLOSED = "CLOSED"
+    CANCELLED = "CANCELLED"
+
+    STATE_CHOICES = [
+        (SCHEDULED, "Scheduled"),
+        (IN_PROGRESS, "In progress"),
+        (CLOSED, "Closed"),
+        (CANCELLED, "Cancelled"),
+    ]
+
+    class Meta:
+        ordering = ["-created_at"]
+
+    id = models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True)
+    created_at = models.DateTimeField(auto_now_add=True)
+    state = models.CharField(choices=STATE_CHOICES, max_length=50)
+    clinic = models.ForeignKey(
+        Clinic, on_delete=models.PROTECT, related_name="statuses"
+    )

manage_breast_screening/clinics/presenters.py

@@ -2,8 +2,8 @@
 
 from ..core.utils.date_formatting import format_date, format_time_range
 from ..core.utils.string_formatting import sentence_case
-from .models import Clinic
 from ..mammograms.presenters import AppointmentPresenter
+from .models import ClinicStatus
 
 
 class ClinicsPresenter:
@@ -26,9 +26,9 @@ def heading(self):
 
 class ClinicPresenter:
     STATUS_COLORS = {
-        Clinic.State.SCHEDULED: "blue",  # default blue
-        Clinic.State.IN_PROGRESS: "blue",
-        Clinic.State.CLOSED: "grey",
+        ClinicStatus.SCHEDULED: "blue",  # default blue
+        ClinicStatus.IN_PROGRESS: "blue",
+        ClinicStatus.CLOSED: "grey",
     }
 
     def __init__(self, clinic):
@@ -44,9 +44,13 @@ def __init__(self, clinic):
 
     @property
     def state(self):
+        status = self._clinic.current_status()
+        value = status.state
+        text = status.get_state_display()
+
         return {
-            "text": self._clinic.get_state_display(),
-            "classes": "nhsuk-tag--" + self.STATUS_COLORS[self._clinic.state],
+            "text": text,
+            "classes": "nhsuk-tag--" + self.STATUS_COLORS[value],
         }
 
     @property

manage_breast_screening/clinics/tests/factories.py

@@ -1,6 +1,7 @@
 from datetime import datetime, timedelta, timezone
 
-from factory.declarations import LazyAttribute, Sequence, SubFactory
+from factory import post_generation
+from factory.declarations import LazyAttribute, RelatedFactoryList, Sequence, SubFactory
 from factory.django import DjangoModelFactory
 from factory.fuzzy import FuzzyChoice
 
@@ -24,20 +25,41 @@ class Meta:
     provider = SubFactory(ProviderFactory)
 
 
+class ClinicStatusFactory(DjangoModelFactory):
+    class Meta:
+        model = models.ClinicStatus
+
+    clinic = None
+    state = models.ClinicStatus.SCHEDULED
+
+
 class ClinicFactory(DjangoModelFactory):
     class Meta:
         model = models.Clinic
         django_get_or_create = ("starts_at", "ends_at")
 
     type = FuzzyChoice(models.Clinic.TYPE_CHOICES)
     risk_type = FuzzyChoice(models.Clinic.RISK_TYPE_CHOICES)
-    state = models.Clinic.State.SCHEDULED
     starts_at = Sequence(
         lambda n: datetime(2025, 1, 1, 9, tzinfo=timezone.utc) + timedelta(hours=n)
     )
     ends_at = LazyAttribute(lambda o: o.starts_at + timedelta(minutes=30))
     setting = SubFactory(SettingFactory)
 
+    # Create a status by default
+    statuses = RelatedFactoryList(
+        ClinicStatusFactory, size=1, factory_related_name="clinic"
+    )
+
+    # Allow passing an explicit status
+    # e.g. `current_status=ClinicStatus.IN_PROGRESS`
+    @post_generation
+    def current_status(obj, create, extracted, **kwargs):
+        if not create or not extracted:
+            return
+
+        obj.statuses.add(ClinicStatusFactory.create(state=extracted, clinic=obj))
+
 
 class ClinicSlotFactory(DjangoModelFactory):
     class Meta:

manage_breast_screening/clinics/tests/test_models.py

@@ -10,9 +10,10 @@
 from .factories import ClinicFactory
 
 
-def test_clinic_is_scheduled():
-    factory = ClinicFactory.build()
-    assert factory.state == models.Clinic.State.SCHEDULED
+@pytest.mark.django_db
+def test_clinic_current_status():
+    clinic = ClinicFactory.create(current_status=models.ClinicStatus.SCHEDULED)
+    assert clinic.current_status().state == models.ClinicStatus.SCHEDULED
 
 
 @pytest.mark.django_db

manage_breast_screening/clinics/tests/test_presenters.py

@@ -1,15 +1,13 @@
+import uuid
 from datetime import datetime
 from unittest.mock import MagicMock
-import uuid
-import pytest
 
+import pytest
 from django.urls import reverse
 
-from manage_breast_screening.clinics.presenters import (
-    ClinicPresenter,
-    AppointmentListPresenter,
-)
-from manage_breast_screening.clinics.models import Clinic
+from ..models import Clinic
+from ..presenters import AppointmentListPresenter, ClinicPresenter
+from .factories import ClinicStatusFactory
 
 
 @pytest.fixture
@@ -26,6 +24,7 @@ def mock_clinic():
     }
     mock.get_type_display.return_value = "Screening"
     mock.get_risk_type_display.return_value = "Routine"
+    mock.current_status.return_value = ClinicStatusFactory.build()
 
     return mock
 
@@ -40,6 +39,10 @@ def test_clinic_presenter(mock_clinic):
     assert presenter.time_range == "9am to 3pm"
     assert presenter.type == "Screening"
     assert presenter.risk_type == "Routine"
+    assert presenter.state == {
+        "classes": "nhsuk-tag--blue",
+        "text": "Scheduled",
+    }
 
 
 class TestAppointmentListPresenter:

manage_breast_screening/clinics/views.py

@@ -7,12 +7,6 @@
 from .models import Clinic
 from ..participants.models import Appointment
 
-STATUS_COLORS = {
-    Clinic.State.SCHEDULED: "blue",  # default blue
-    Clinic.State.IN_PROGRESS: "blue",
-    Clinic.State.CLOSED: "grey",
-}
-
 
 def clinic_list(request, filter="today"):
     clinics = Clinic.objects.prefetch_related("setting").by_filter(filter)