Cache triage status in database (#3268)

This introduces a new model, `Patient::TriageStatus`, which stores the
triage status of a patient-programme pair in the database so it can
queried and rendered quickly. Locally, I'm seeing the triage tab on
sessions with 50,000 patients load almost instantly even when filtering
on statuses. The session overview page has a slight improvement, but
that will only load quickly once the other statuses are cached.

I've decided not to implement a state machine as had been previously
discussed, but this could be built on top of this change to enhancement
the functionality. For now, this effectively caches the existing logic
that runs on the fly to the database.

I've also decided not to implement this using Rails callbacks and
instead be explicit where the status is refreshed. This allows us to
optimise for bulk refreshes, as is necessary when adding new programmes
to sessions, running the seeds, or generally updating the status of an
entire session.

This follows up from #3263 which applies the same to the consents.

Author: thomasleese

app/components/app_outcome_banner_component.rb

@@ -58,7 +58,7 @@ def vaccination_record
   end
 
   def triage
-    @triage ||= patient.triage_outcome.latest[programme]
+    @triage ||= patient.latest_triage(programme:)
   end
 
   def session_attendance

app/components/app_patient_page_component.html.erb

@@ -72,14 +72,14 @@
       ) %>
 <% end %>
 
-<% if patient.triage_outcome.all[programme].any? %>
+<% if patient.triages.exists?(programme:) %>
   <%= render AppCardComponent.new do |c| %>
     <% c.with_heading { "Triage notes" } %>
     <%= render AppTriageNotesComponent.new(patient_session:, programme:) %>
   <% end %>
 <% end %>
 
-<% if helpers.policy(Triage).create? && patient.triage_outcome.required?(programme) %>
+<% if helpers.policy(Triage).create? && patient.triage_status(programme:).required? %>
   <%= render AppCardComponent.new do %>
     <%= render AppTriageFormComponent.new(
           patient_session:,

app/components/app_patient_session_search_result_card_component.rb

@@ -83,24 +83,25 @@ def action_required
   def status_tag
     return if context == :record
 
-    if context == :register
+    case context
+    when :register
       render AppRegisterStatusTagComponent.new(
                patient_session.register_outcome.status
              )
-    elsif context == :consent
+    when :consent
       statuses =
         patient_session.programmes.index_with do |programme|
           patient.consent_status(programme:).status
         end
       render AppProgrammeStatusTagsComponent.new(statuses, outcome: :consent)
-    else
-      outcome =
-        case context
-        when :triage
-          patient.triage_outcome
-        when :outcome
-          patient_session.session_outcome
+    when :triage
+      statuses =
+        patient_session.programmes.index_with do |programme|
+          patient.triage_status(programme:).status
         end
+      render AppProgrammeStatusTagsComponent.new(statuses, outcome: :triage)
+    else
+      outcome = patient_session.session_outcome
 
       # ensure status is calculated for each programme
       patient_session.programmes.each { outcome.status[it] }

app/components/app_programme_session_table_component.rb

@@ -43,7 +43,9 @@ def no_response_percentage(session:)
   end
 
   def triage_needed_count(session:)
-    number_stat(session:) { it.patient.triage_outcome.required?(programme) }
+    format_number(
+      session.patient_sessions.has_triage_status(:required, programme:).count
+    )
   end
 
   def vaccinated_count(session:)

app/components/app_session_actions_component.rb

@@ -62,12 +62,10 @@ def consent_row(text, status:)
   end
 
   def triage_required_row
-    status = Patient::TriageOutcome::REQUIRED
+    status = "required"
 
     count =
-      patient_sessions.count do
-        it.patient.triage_outcome.status.values_at(*it.programmes).any?(status)
-      end
+      patient_sessions.has_triage_status(status, programme: programmes).count
 
     return nil if count.zero?
 

app/components/app_simple_status_banner_component.rb

@@ -50,9 +50,11 @@ def description
       programme_name: programme.name
     }
 
-    if patient.triage_outcome.required?(programme)
+    triage_status = patient.triage_status(programme:)
+
+    if triage_status.required?
       reasons = [
-        if patient.consent_status(programme:).health_answers_require_follow_up?
+        if triage_status.consent_requires_triage?
           I18n.t(
             :consent_needs_triage,
             scope: %i[
@@ -63,7 +65,7 @@ def description
             **options
           )
         end,
-        if patient.triage_outcome.vaccination_history_needs_triage?(programme:)
+        if triage_status.vaccination_history_requires_triage?
           I18n.t(
             :vaccination_partially_administered,
             scope: %i[
@@ -92,7 +94,7 @@ def who_refused
 
   def nurse
     (
-      patient.triage_outcome.all[programme] +
+      patient.triages.includes(:performed_by).where(programme:) +
         patient.programme_outcome.all[programme]
     ).max_by(&:updated_at)&.performed_by&.full_name
   end

app/components/app_triage_form_component.rb

@@ -16,10 +16,7 @@ def initialize(
     @triage =
       triage ||
         Triage.new.tap do |t|
-          if (
-               latest_triage =
-                 patient_session.patient.triage_outcome.latest[programme]
-             )
+          if (latest_triage = patient_session.patient.latest_triage(programme:))
             t.status = latest_triage.status
           end
         end

app/controllers/concerns/triage_mailer_concern.rb

@@ -40,18 +40,18 @@ def send_triage_confirmation(patient_session, consent)
   def vaccination_will_happen?(patient, consent)
     programme = consent.programme
     consent.triage_needed? &&
-      patient.triage_outcome.safe_to_vaccinate?(programme)
+      patient.triage_status(programme:).safe_to_vaccinate?
   end
 
   def vaccination_wont_happen?(patient, consent)
     programme = consent.programme
     consent.triage_needed? &&
-      patient.triage_outcome.do_not_vaccinate?(programme)
+      patient.triage_status(programme:).do_not_vaccinate?
   end
 
   def vaccination_at_clinic?(patient, consent)
     programme = consent.programme
     consent.triage_needed? &&
-      patient.triage_outcome.delay_vaccination?(programme)
+      patient.triage_status(programme:).delay_vaccination?
   end
 end

app/controllers/draft_consents_controller.rb

@@ -63,7 +63,7 @@ def handle_confirm
       StatusUpdater.call(patient: @patient)
     end
 
-    set_patient_session # reload with new consents
+    set_patient_session # reload with new statuses
 
     send_triage_confirmation(@patient_session, @consent)
 

app/controllers/patient_sessions_controller.rb

@@ -54,6 +54,7 @@ def set_patient_session
           patient: {
             consents: %i[parent],
             parent_relationships: :parent,
+            triage_statuses: :programme,
             triages: :performed_by,
             vaccination_records: {
               vaccine: :programme