Match against patients in upload before DB in ImmsImports

This change caches all patients in the upload so far and re-orders
the patient matching to match against in-memory cache before
consulting the DB.

Jira-Issue: MAV-3928

Author: alistair-white-horne-tng

app/models/immunisation_import.rb

@@ -75,14 +75,15 @@ def parse_row(data)
   end
 
   def process_row(row)
-    patient = row.set_patient(candidates: @patients_batch)
+    patient = row.set_patient(candidates: @all_patients)
     vaccination_record = row.to_vaccination_record
 
     count_column_to_increment = count_column(vaccination_record)
     return count_column_to_increment unless vaccination_record
 
     @vaccination_records_batch.add(vaccination_record)
     @patients_batch.add(patient)
+    @all_patients.add(patient)
 
     if (patient_location = row.to_patient_location)
       @patient_locations_batch.add(patient_location)
@@ -100,6 +101,7 @@ def process_import!
 
     @vaccination_records_batch = Set.new
     @patients_batch = Set.new
+    @all_patients = Set.new
     @patient_locations_batch = Set.new
     @archive_reasons_batch = Set.new
 

app/models/immunisation_import_row.rb

@@ -480,23 +480,24 @@ def existing_patients(candidates: nil)
       return
     end
 
-    database_matches =
-      PatientMatcher.from_relation(
-        Patient,
-        nhs_number: patient_nhs_number_value,
-        given_name: patient_first_name.to_s,
-        family_name: patient_last_name.to_s,
-        date_of_birth: patient_date_of_birth.to_date,
-        address_postcode: patient_postcode&.to_postcode,
-        include_3_out_of_4_matches: false
-      )
-
-    return database_matches if database_matches.present?
+    if candidates.present?
+      # Match against the in-memory list of patients so far in this upload, before matching against the database
+      candidate_matches =
+        PatientMatcher.from_enumerable(
+          candidates,
+          nhs_number: patient_nhs_number_value,
+          given_name: patient_first_name.to_s,
+          family_name: patient_last_name.to_s,
+          date_of_birth: patient_date_of_birth.to_date,
+          address_postcode: patient_postcode&.to_postcode,
+          include_3_out_of_4_matches: false
+        )
 
-    return if candidates.blank?
+      return candidate_matches if candidate_matches.present?
+    end
 
-    PatientMatcher.from_enumerable(
-      candidates,
+    PatientMatcher.from_relation(
+      Patient,
       nhs_number: patient_nhs_number_value,
       given_name: patient_first_name.to_s,
       family_name: patient_last_name.to_s,