Refactor AppVaccinateFormComponent

This refactors the component to be based around the vaccine method
rather than the delivery method. This allows us to simplify the code
while also preparing for a future feature which allows nurses to choose
from multiple vaccine methods.

Jira-Issue: MAV-1338

Author: thomasleese

app/components/app_vaccinate_form_component.rb

@@ -18,21 +18,21 @@ def url
     session_patient_programme_vaccinations_path(session, patient, programme)
   end
 
+  def vaccine_method
+    patient.approved_vaccine_methods(programme:).first
+  end
+
   def delivery_method
-    if patient.approved_vaccine_methods(programme:).include?("nasal")
-      "nasal_spray"
-    else
-      "intramuscular"
-    end
+    Vaccine::AVAILABLE_DELIVERY_METHODS.fetch(vaccine_method).first
   end
 
   def dose_sequence
     programme.default_dose_sequence
   end
 
   COMMON_DELIVERY_SITES = {
-    "intramuscular" => %w[left_arm_upper_position right_arm_upper_position],
-    "nasal_spray" => %w[nose]
+    "injection" => %w[left_arm_upper_position right_arm_upper_position],
+    "nasal" => %w[nose]
   }.freeze
 
   CommonDeliverySite = Struct.new(:value, :label)
@@ -42,13 +42,13 @@ def common_delivery_sites_options
       begin
         options =
           COMMON_DELIVERY_SITES
-            .fetch(delivery_method)
+            .fetch(vaccine_method)
             .map do |value|
               label = VaccinationRecord.human_enum_name(:delivery_site, value)
               CommonDeliverySite.new(value:, label:)
             end
 
-        if delivery_method.in?(Vaccine::INJECTION_DELIVERY_METHODS)
+        if vaccine_method == "injection"
           options << CommonDeliverySite.new(value: "other", label: "Other")
         end
 
@@ -59,8 +59,6 @@ def common_delivery_sites_options
   def vaccination_name
     vaccination =
       if programme.has_multiple_vaccine_methods?
-        vaccine_method =
-          Vaccine.delivery_method_to_vaccine_method(delivery_method)
         Vaccine.human_enum_name(:method, vaccine_method).downcase
       else
         "vaccination"
@@ -73,6 +71,5 @@ def ask_not_taking_medication? = programme.doubles? || programme.flu?
 
   def ask_not_pregnant? = programme.td_ipv?
 
-  def ask_asthma_flare_up? =
-    delivery_method.in?(Vaccine::NASAL_DELIVERY_METHODS)
+  def ask_asthma_flare_up? = vaccine_method == "nasal"
 end

app/models/draft_vaccination_record.rb

@@ -296,10 +296,12 @@ def reset_unused_fields
     end
   end
 
-  def can_be_half_dose?
-    delivery_method.in?(Vaccine::NASAL_DELIVERY_METHODS)
+  def vaccine_method
+    Vaccine.delivery_method_to_vaccine_method(delivery_method)
   end
 
+  def can_be_half_dose? = vaccine_method == "nasal"
+
   def can_change_outcome?
     outcome != "already_had" || editing? || session.nil? || session.today?
   end
@@ -312,14 +314,14 @@ def delivery_site_matches_delivery_method
       return
     end
 
-    case delivery_method
-    when *Vaccine::NASAL_DELIVERY_METHODS
-      if delivery_site != "nose"
-        errors.add(:delivery_site, :nasal_spray_must_be_nose)
-      end
-    when *Vaccine::INJECTION_DELIVERY_METHODS
-      if delivery_site == "nose"
+    allowed_delivery_sites =
+      Vaccine::AVAILABLE_DELIVERY_SITES.fetch(vaccine_method)
+
+    unless delivery_site.in?(allowed_delivery_sites)
+      if vaccine_method == "injection"
         errors.add(:delivery_site, :injection_cannot_be_nose)
+      else
+        errors.add(:delivery_site, :nasal_spray_must_be_nose)
       end
     end
 

app/models/vaccine.rb

@@ -77,12 +77,9 @@ def available_delivery_sites
     AVAILABLE_DELIVERY_SITES.fetch(method)
   end
 
-  NASAL_DELIVERY_METHODS = %w[nasal_spray].freeze
-  INJECTION_DELIVERY_METHODS = %w[intramuscular subcutaneous].freeze
-
   AVAILABLE_DELIVERY_METHODS = {
-    "nasal" => NASAL_DELIVERY_METHODS,
-    "injection" => INJECTION_DELIVERY_METHODS
+    "nasal" => %w[nasal_spray].freeze,
+    "injection" => %w[intramuscular subcutaneous].freeze
   }.freeze
 
   def available_delivery_methods