Add Patient#approved_vaccine_methods

This adds a method which encapsulates the logic related to determining
the vaccine methods that are approved for a particular patient. This
refactors existing the logic, but this method will then be used when
generating personalisation variables for the emails and texts.

Author: thomasleese

app/components/app_vaccinate_form_component.rb

@@ -19,16 +19,11 @@ def url
   end
 
   def delivery_method
-    triage_status = patient.triage_status(programme:)
-
-    status =
-      if triage_status.not_required?
-        patient.consent_status(programme:)
-      else
-        triage_status
-      end
-
-    status.vaccine_method_nasal? ? :nasal_spray : :intramuscular
+    if patient.approved_vaccine_methods(programme:).include?("nasal")
+      :nasal_spray
+    else
+      :intramuscular
+    end
   end
 
   def dose_sequence

app/models/patient.rb

@@ -338,6 +338,16 @@ def consent_given_and_safe_to_vaccinate?(programme:)
       )
   end
 
+  def approved_vaccine_methods(programme:)
+    triage_status = triage_status(programme:)
+
+    if triage_status.not_required?
+      consent_status(programme:).vaccine_methods
+    else
+      [triage_status.vaccine_method].compact
+    end
+  end
+
   def deceased?
     date_of_death != nil
   end

spec/models/patient_spec.rb

@@ -321,6 +321,57 @@
     it { should eq("JD") }
   end
 
+  describe "#approved_vaccine_methods" do
+    subject(:approved_vaccine_methods) do
+      patient.approved_vaccine_methods(programme:)
+    end
+
+    let(:patient) { create(:patient) }
+    let(:programme) { create(:programme) }
+
+    it { should be_empty }
+
+    context "when consent given and triage not required" do
+      before do
+        create(
+          :patient_consent_status,
+          :given,
+          patient:,
+          programme:,
+          vaccine_methods: %w[nasal injection]
+        )
+      end
+
+      it { should eq(%w[nasal injection]) }
+    end
+
+    context "when consent given and triage required" do
+      before do
+        create(
+          :patient_consent_status,
+          :given,
+          patient:,
+          programme:,
+          vaccine_methods: %w[nasal injection]
+        )
+        create(:patient_triage_status, :required, patient:, programme:)
+      end
+
+      it { should be_empty }
+
+      context "and when triaged" do
+        before do
+          patient.triage_status(programme:).update!(
+            status: "safe_to_vaccinate",
+            vaccine_method: "nasal"
+          )
+        end
+
+        it { should eq(%w[nasal]) }
+      end
+    end
+  end
+
   describe "#update_from_pds!" do
     subject(:update_from_pds!) { patient.update_from_pds!(pds_patient) }