Allow triage performed by to be optional

This updates the `performed_by_user_id` column on triages to be `NOT
NULL`, allowing it to not be specified when we don't have a suitable
user.

The only place this will be set to `NULL` for now is when creating the
automatic next dose delay triage.

Jira-Issue: MAV-2991

Author: thomasleese

app/components/app_patient_session_triage_component.html.erb

@@ -29,16 +29,8 @@
       <p>A nurse needs to decide if <%= patient.full_name %> is safe to vaccinate.</p>
     <% end %>
   <% elsif latest_triage %>
-    <% if latest_triage.safe_to_vaccinate? %>
-      <% if latest_triage.vaccine_method.present? && programme.has_multiple_vaccine_methods? %>
-        <p><%= latest_triage.performed_by.full_name %> decided that <%= patient.full_name %> is safe to vaccinate using the <%= vaccination_method %> vaccine only.</p>
-      <% else %>
-        <p><%= latest_triage.performed_by.full_name %> decided that <%= patient.full_name %> is safe to vaccinate.</p>
-      <% end %>
-    <% elsif latest_triage.do_not_vaccinate? %>
-      <p><%= latest_triage.performed_by.full_name %> decided that <%= patient.full_name %> should not be vaccinated.</p>
-    <% elsif latest_triage.delay_vaccination? %>
-      <p><%= latest_triage.performed_by.full_name %> decided that <%= patient.full_name %>'s vaccination should be delayed.</p>
+    <% if (summary = triage_summary(latest_triage)) %>
+      <p><%= summary %></p>
     <% end %>
 
     <div class="nhsuk-button-group">

app/components/app_patient_session_triage_component.rb

@@ -19,7 +19,7 @@ def render? = consent_status.given? || !triage_status.not_required?
 
   attr_reader :current_user, :triage_form
 
-  delegate :govuk_button_link_to, to: :helpers
+  delegate :govuk_button_link_to, :triage_summary, to: :helpers
 
   def programme_type = programme.type
 
@@ -39,10 +39,6 @@ def consent_status
     patient.consent_status(programme:, academic_year:)
   end
 
-  def vaccination_method
-    Vaccine.human_enum_name(:method_prefix, triage_status.vaccine_method)
-  end
-
   def latest_triage
     @latest_triage ||=
       TriageFinder.call(

app/components/app_triage_table_component.html.erb

@@ -14,10 +14,12 @@
       <% body.with_row do |row| %>
         <% row.with_cell do %>
           <%= triage.created_at.to_fs(:long) %>
-          <br />
-          <span class="nhsuk-u-secondary-text-colour nhsuk-u-font-size-16">
-            <%= triage.performed_by.full_name %>
-          </span>
+          <% if (performed_by = triage.performed_by) %>
+            <br />
+            <span class="nhsuk-u-secondary-text-colour nhsuk-u-font-size-16">
+              <%= performed_by.full_name %>
+            </span>
+          <% end %>
         <% end %>
 
         <% row.with_cell(text: triage.notes) %>

app/helpers/triages_helper.rb

@@ -48,4 +48,31 @@ def triage_status_tag(triage)
       govuk_tag(text:, classes: "nhsuk-tag--#{colour}")
     end
   end
+
+  def triage_summary(triage)
+    prefix =
+      if (performed_by = triage.performed_by)
+        "#{performed_by.full_name} decided that "
+      else
+        ""
+      end
+
+    suffix =
+      if triage.safe_to_vaccinate?
+        if triage.vaccine_method.present? &&
+             triage.programme.has_multiple_vaccine_methods?
+          vaccination_method =
+            Vaccine.human_enum_name(:method_prefix, triage.vaccine_method)
+          "is safe to vaccinate using the #{vaccination_method} vaccine only."
+        else
+          "is safe to vaccinate."
+        end
+      elsif triage.do_not_vaccinate?
+        "should not be vaccinated."
+      elsif triage.delay_vaccination?
+        "’s vaccination should be delayed."
+      end
+
+    "#{prefix}#{triage.patient.full_name} #{suffix}" if suffix
+  end
 end

app/models/triage.rb

@@ -16,7 +16,7 @@
 #  created_at              :datetime         not null
 #  updated_at              :datetime         not null
 #  patient_id              :bigint           not null
-#  performed_by_user_id    :bigint           not null
+#  performed_by_user_id    :bigint
 #  team_id                 :bigint           not null
 #
 # Indexes
@@ -37,12 +37,15 @@ class Triage < ApplicationRecord
   include BelongsToProgramme
   include Invalidatable
   include Notable
-  include PerformableByUser
 
   audited associated_with: :patient
 
   belongs_to :patient
   belongs_to :team
+  belongs_to :performed_by,
+             class_name: "User",
+             foreign_key: :performed_by_user_id,
+             optional: true
 
   enum :status,
        {

db/migrate/20260108143705_make_triage_performed_by_null.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class MakeTriagePerformedByNull < ActiveRecord::Migration[8.1]
+  def change
+    change_column_null :triages, :performed_by_user_id, true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.1].define(version: 2026_01_07_194410) do
+ActiveRecord::Schema[8.1].define(version: 2026_01_08_143705) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_catalog.plpgsql"
   enable_extension "pg_trgm"
@@ -893,7 +893,7 @@
     t.datetime "invalidated_at"
     t.text "notes", default: "", null: false
     t.bigint "patient_id", null: false
-    t.bigint "performed_by_user_id", null: false
+    t.bigint "performed_by_user_id"
     t.enum "programme_type", null: false, enum_type: "programme_type"
     t.integer "status", null: false
     t.bigint "team_id", null: false

spec/components/app_triage_table_component_spec.rb

@@ -25,21 +25,27 @@
     subject { render_inline(component) }
 
     context "triaged as safe to vaccinate" do
-      let!(:triage) do
-        create(:triage, :safe_to_vaccinate, patient:, programme:)
-      end
+      before { create(:triage, :safe_to_vaccinate, patient:, programme:) }
 
       it { should have_css("caption", text: "Triage notes") }
       it { should have_content("Safe to vaccinate") }
-      it { should have_content(triage.performed_by.full_name) }
     end
 
     context "triaged as unsafe to vaccinate" do
-      let!(:triage) { create(:triage, :do_not_vaccinate, patient:, programme:) }
+      before { create(:triage, :do_not_vaccinate, patient:, programme:) }
 
       it { should have_css("caption", text: "Triage notes") }
       it { should have_content("Do not vaccinate") }
-      it { should have_content(triage.performed_by.full_name) }
+    end
+
+    context "with a performed by user" do
+      before do
+        create(:triage, :safe_to_vaccinate, patient:, programme:, performed_by:)
+      end
+
+      let(:performed_by) { create(:nurse) }
+
+      it { should have_content(performed_by.full_name) }
     end
   end
 end

spec/factories/triages.rb

@@ -16,7 +16,7 @@
 #  created_at              :datetime         not null
 #  updated_at              :datetime         not null
 #  patient_id              :bigint           not null
-#  performed_by_user_id    :bigint           not null
+#  performed_by_user_id    :bigint
 #  team_id                 :bigint           not null
 #
 # Indexes
@@ -38,8 +38,7 @@
     patient
     programme { Programme.sample }
 
-    performed_by
-    team { performed_by.teams.first }
+    team
 
     notes { "" }
 

spec/models/triage_spec.rb

@@ -16,7 +16,7 @@
 #  created_at              :datetime         not null
 #  updated_at              :datetime         not null
 #  patient_id              :bigint           not null
-#  performed_by_user_id    :bigint           not null
+#  performed_by_user_id    :bigint
 #  team_id                 :bigint           not null
 #
 # Indexes
@@ -40,7 +40,7 @@
   describe "associations" do
     it { should belong_to(:patient) }
     it { should belong_to(:team) }
-    it { should belong_to(:performed_by) }
+    it { should belong_to(:performed_by).optional(true) }
   end
 
   describe "validations" do