Fix start appointment visibility and state guard

The start appointment link is currently appearing for clinical users
even if an appointment has already been started by another user. We also
don't confirm appointment state before attempting to update it in the
start_appointment view.

- Template delegates start link visibility to `can_be_started_by(user)`
  on the presented appointment, instead of checking a permission
  directly.

- View now guards against starting an already-in-progress appointment:
  if the state machine can't transition, it redirects to the in-progress
  tab with a warning naming who started it.

Author: malcolmbaig

manage_breast_screening/core/jinja2/components/start-appointment/template.jinja

@@ -2,7 +2,7 @@
   {{ raise('start_appointment_url is required') }}
 {% endif %}
 
-{% if user.has_perm('mammograms.do_mammogram_appointment') %}
+{% if presented_appointment.can_be_started_by(user) %}
 <div data-module="app-start-appointment" data-appointment-id="{{ presented_appointment.pk }}" {% if presented_appointment.can_be_checked_in %}hidden{% endif %}>
   <form action="{{ start_appointment_url }}" method="post" novalidate>
     <p>

manage_breast_screening/core/tests/jinja2/test_start_appointment.py

@@ -17,9 +17,9 @@ def presented_appointment():
     return mock
 
 
-def render(template, user_has_perm, presented_appointment):
+def render(template, can_be_started_by, presented_appointment):
     user = MagicMock()
-    user.has_perm.return_value = user_has_perm
+    presented_appointment.can_be_started_by.return_value = can_be_started_by
     return template.render(
         {
             "user": user,
@@ -30,24 +30,28 @@ def render(template, user_has_perm, presented_appointment):
     )
 
 
-def test_renders_start_button_for_clinical_user(template, presented_appointment):
+def test_renders_start_button_when_appointment_can_be_started(
+    template, presented_appointment
+):
     html = render(
-        template, user_has_perm=True, presented_appointment=presented_appointment
+        template, can_be_started_by=True, presented_appointment=presented_appointment
     )
     assert 'data-module="app-start-appointment"' in html
 
 
-def test_does_not_render_start_button_for_admin_user(template, presented_appointment):
+def test_does_not_render_start_button_when_appointment_cannot_be_started(
+    template, presented_appointment
+):
     html = render(
-        template, user_has_perm=False, presented_appointment=presented_appointment
+        template, can_be_started_by=False, presented_appointment=presented_appointment
     )
     assert 'data-module="app-start-appointment"' not in html
 
 
 def test_renders_button_hidden_before_checkin(template, presented_appointment):
     presented_appointment.can_be_checked_in = True
     html = render(
-        template, user_has_perm=True, presented_appointment=presented_appointment
+        template, can_be_started_by=True, presented_appointment=presented_appointment
     )
     assert 'data-module="app-start-appointment"' in html
     assert 'data-appointment-id="abc-123" hidden' in html
@@ -56,7 +60,7 @@ def test_renders_button_hidden_before_checkin(template, presented_appointment):
 def test_renders_button_visible_after_checkin(template, presented_appointment):
     presented_appointment.can_be_checked_in = False
     html = render(
-        template, user_has_perm=True, presented_appointment=presented_appointment
+        template, can_be_started_by=True, presented_appointment=presented_appointment
     )
     assert 'data-module="app-start-appointment"' in html
     assert 'data-appointment-id="abc-123" hidden' not in html

manage_breast_screening/mammograms/tests/views/test_appointment_workflow_views.py

@@ -3,10 +3,12 @@
 import django
 import pytest
 import statemachine
+from django.contrib import messages
 from django.urls import reverse
 from pytest_django.asserts import (
     assertContains,
     assertInHTML,
+    assertMessages,
     assertNotContains,
     assertQuerySetEqual,
     assertRedirects,
@@ -534,6 +536,38 @@ def test_user_not_permitted(self, administrative_user_client):
         response = administrative_user_client.http.post(url)
         assert response.status_code == 403
 
+    def test_redirects_to_in_progress_tab_with_warning_when_already_started(
+        self, clinical_user_client
+    ):
+        other_user = UserFactory.create(first_name="Alice", last_name="Smith")
+        appointment = AppointmentFactory.create(
+            clinic_slot__clinic__setting__provider=clinical_user_client.current_provider,
+            current_status_params={
+                "name": AppointmentStatusNames.IN_PROGRESS,
+                "created_by": other_user,
+            },
+        )
+        response = clinical_user_client.http.post(
+            reverse("mammograms:start_appointment", kwargs={"pk": appointment.pk})
+        )
+        assertRedirects(
+            response,
+            reverse(
+                "clinics:list_clinic_appointments_in_progress",
+                kwargs={"pk": appointment.clinic_slot.clinic.pk},
+            ),
+        )
+        patient_name = appointment.participant.full_name
+        assertMessages(
+            response,
+            [
+                messages.Message(
+                    level=messages.WARNING,
+                    message=f"Appointment for {patient_name} has already been started by {other_user.get_short_name()}.",
+                )
+            ],
+        )
+
 
 @pytest.mark.django_db
 class TestResumeAppointment:

manage_breast_screening/mammograms/views/appointment_workflow_views.py

@@ -43,6 +43,7 @@
     ParticipantReportedMammogram,
 )
 from manage_breast_screening.participants.models.appointment import (
+    AppointmentMachine,
     AppointmentWorkflowStepCompletion,
 )
 from manage_breast_screening.participants.presenters import ParticipantPresenter
@@ -309,6 +310,19 @@ def start_appointment(request, pk):
     except Appointment.DoesNotExist:
         raise Http404("Appointment not found")
 
+    if not AppointmentMachine.from_appointment(appointment).can("start"):
+        patient_name = appointment.participant.full_name
+        started_by = appointment.current_status.created_by.get_short_name()
+        messages.add_message(
+            request,
+            messages.WARNING,
+            f"Appointment for {patient_name} has already been started by {started_by}.",
+        )
+        return redirect(
+            "clinics:list_clinic_appointments_in_progress",
+            pk=appointment.clinic_slot.clinic.pk,
+        )
+
     AppointmentStatusUpdater(appointment=appointment, current_user=request.user).start()
 
     return redirect("mammograms:confirm_identity", pk=pk)