Replace registration status patient session foreign key

This replaces the foreign key association between registration statuses
and patient sessions to instead link directly to the patient. This is
needed as we eventually want to replace the PatientSession model and to
do that we need to make sure all foreign keys to it have been replaced.

The functionality should be the same before and after.

Jira-Issue: MAV-1821

Author: thomasleese

app/lib/status_generator/registration.rb

@@ -1,8 +1,9 @@
 # frozen_string_literal: true
 
 class StatusGenerator::Registration
-  def initialize(patient_session:, session_attendance:, vaccination_records:)
-    @patient_session = patient_session
+  def initialize(patient:, session:, session_attendance:, vaccination_records:)
+    @patient = patient
+    @session = session
     @session_attendance = session_attendance
     @vaccination_records = vaccination_records
   end
@@ -21,17 +22,18 @@ def status
 
   private
 
-  attr_reader :patient_session, :session_attendance, :vaccination_records
+  attr_reader :patient, :session, :session_attendance, :vaccination_records
 
-  def academic_year = patient_session.session.academic_year
+  delegate :academic_year, to: :session
 
   def status_should_be_completed?
-    patient_session.programmes.all? do |programme|
-      vaccination_records.any? do
-        it.programme_id == programme.id &&
-          it.session_id == patient_session.session_id
+    session
+      .programmes_for(patient:, academic_year:)
+      .all? do |programme|
+        vaccination_records.any? do
+          it.programme_id == programme.id && it.session_id == session.id
+        end
       end
-    end
   end
 
   def status_should_be_attending?

app/lib/status_updater.rb

@@ -50,20 +50,22 @@ def update_consent_statuses!
 
   def update_registration_statuses!
     Patient::RegistrationStatus.import!(
-      %i[patient_session_id],
-      registration_statuses_to_import,
+      %i[patient_id session_id],
+      patient_session_statuses_to_import,
       on_duplicate_key_ignore: true
     )
 
     Patient::RegistrationStatus
-      .where(patient_session_id: patient_sessions.select(:id))
+      .where(
+        patient: patient_sessions.select(:patient_id),
+        session: patient_sessions.select(:session_id)
+      )
       .includes(
+        :patient,
         :session_attendances,
         :session_date,
         :vaccination_records,
-        patient_session: {
-          session: :programmes
-        }
+        session: :programmes
       )
       .find_in_batches(batch_size: 10_000) do |batch|
         batch.each(&:assign_status)
@@ -167,23 +169,24 @@ def patient_session_statuses_to_import
     patient_sessions
       .joins(:patient, :session)
       .pluck(
-        :id,
-        :"session.location_id",
-        :"session.academic_year",
+        :"patients.id",
+        :"sessions.id",
+        :"sessions.location_id",
+        :"sessions.academic_year",
         :"patients.birth_academic_year"
       )
-      .flat_map do |patient_session_id, location_id, academic_year, birth_academic_year|
+      .filter_map do |patient_id, session_id, location_id, academic_year, birth_academic_year|
         year_group = birth_academic_year.to_year_group(academic_year:)
 
-        programme_ids_per_location_id_and_year_group
-          .fetch(location_id, {})
-          .fetch(year_group, [])
-          .map { [patient_session_id, it] }
-      end
-  end
+        if programme_ids_per_location_id_and_year_group
+             .fetch(location_id, {})
+             .fetch(year_group, [])
+             .empty?
+          next
+        end
 
-  def registration_statuses_to_import
-    patient_session_statuses_to_import.map { [it.first] }.uniq
+        [patient_id, session_id]
+      end
   end
 
   def programme_ids_per_year_group

app/models/patient.rb

@@ -72,6 +72,7 @@ class Patient < ApplicationRecord
   has_many :patient_sessions
   has_many :pds_search_results
   has_many :pre_screenings
+  has_many :registration_statuses
   has_many :school_move_log_entries
   has_many :school_moves
   has_many :session_attendances

app/models/patient/registration_status.rb

@@ -4,24 +4,26 @@
 #
 # Table name: patient_registration_statuses
 #
-#  id                 :bigint           not null, primary key
-#  status             :integer          default("unknown"), not null
-#  patient_session_id :bigint           not null
+#  id         :bigint           not null, primary key
+#  status     :integer          default("unknown"), not null
+#  patient_id :bigint           not null
+#  session_id :bigint           not null
 #
 # Indexes
 #
-#  index_patient_registration_statuses_on_patient_session_id  (patient_session_id) UNIQUE
-#  index_patient_registration_statuses_on_status              (status)
+#  idx_on_patient_id_session_id_2ff02d8889            (patient_id,session_id) UNIQUE
+#  index_patient_registration_statuses_on_patient_id  (patient_id)
+#  index_patient_registration_statuses_on_session_id  (session_id)
+#  index_patient_registration_statuses_on_status      (status)
 #
 # Foreign Keys
 #
-#  fk_rails_...  (patient_session_id => patient_sessions.id) ON DELETE => cascade
+#  fk_rails_...  (patient_id => patients.id) ON DELETE => cascade
+#  fk_rails_...  (session_id => sessions.id) ON DELETE => cascade
 #
 class Patient::RegistrationStatus < ApplicationRecord
-  belongs_to :patient_session
-
-  has_one :patient, through: :patient_session
-  has_one :session, through: :patient_session
+  belongs_to :patient
+  belongs_to :session
 
   has_many :vaccination_records,
            -> { kept.order(performed_at: :desc) },
@@ -49,7 +51,8 @@ def assign_status
   def generator
     @generator ||=
       StatusGenerator::Registration.new(
-        patient_session:,
+        patient:,
+        session:,
         session_attendance:,
         vaccination_records:
       )

app/models/patient_session.rb

@@ -44,8 +44,6 @@ class PatientSession < ApplicationRecord
   belongs_to :patient
   belongs_to :session
 
-  has_one :registration_status, class_name: "Patient::RegistrationStatus"
-
   has_one :location, through: :session
   has_one :subteam, through: :session
   has_one :team, through: :session
@@ -66,6 +64,12 @@ class PatientSession < ApplicationRecord
            -> { where(patient_id: it.patient_id) },
            through: :session
 
+  has_one :registration_status,
+          -> { where(session_id: it.session_id) },
+          through: :patient,
+          source: :registration_statuses,
+          class_name: "Patient::RegistrationStatus"
+
   has_many :session_attendances,
            -> { where(patient_id: it.patient_id) },
            through: :session
@@ -188,7 +192,8 @@ class PatientSession < ApplicationRecord
         ->(status) do
           where(
             Patient::RegistrationStatus
-              .where("patient_session_id = patient_sessions.id")
+              .where("patient_id = patient_sessions.patient_id")
+              .where("session_id = patient_sessions.session_id")
               .where(status:)
               .arel
               .exists

db/migrate/20250822153747_remove_patient_session_from_patient_registration_statuses.rb

@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+class RemovePatientSessionFromPatientRegistrationStatuses < ActiveRecord::Migration[
+  8.0
+]
+  def up
+    change_table :patient_registration_statuses, bulk: true do |t|
+      t.references :patient, foreign_key: { on_delete: :cascade }
+      t.references :session, foreign_key: { on_delete: :cascade }
+      t.index %i[patient_id session_id], unique: true
+    end
+
+    Patient::RegistrationStatus.find_each do |registration_status|
+      patient_session =
+        PatientSession.find(registration_status.patient_session_id)
+      patient_id = patient_session.patient_id
+      session_id = patient_session.session_id
+      registration_status.update_columns(patient_id:, session_id:)
+    end
+
+    change_table :patient_registration_statuses, bulk: true do |t|
+      t.change_null :patient_id, false
+      t.change_null :session_id, false
+      t.remove_references :patient_session
+    end
+  end
+
+  def down
+    change_table :patient_registration_statuses, bulk: true do |t|
+      t.references :patient_session, foreign_key: { on_delete: :cascade }
+      t.index :patient_session_id, unique: true
+    end
+
+    Patient::RegistrationStatus.find_each do |registration_status|
+      patient_id = registration_status.patient_id
+      session_id = registration_status.session_id
+      patient_session = PatientSession.find_by!(patient_id:, session_id:)
+      registration_status.update_column(:patient_session_id, patient_session.id)
+    end
+
+    change_table :patient_registration_statuses, bulk: true do |t|
+      t.change_null :patient_session_id, false
+      t.remove_references :patient, :session
+    end
+  end
+end

db/schema.rb

@@ -619,9 +619,12 @@
   end
 
   create_table "patient_registration_statuses", force: :cascade do |t|
-    t.bigint "patient_session_id", null: false
     t.integer "status", default: 0, null: false
-    t.index ["patient_session_id"], name: "index_patient_registration_statuses_on_patient_session_id", unique: true
+    t.bigint "patient_id", null: false
+    t.bigint "session_id", null: false
+    t.index ["patient_id", "session_id"], name: "idx_on_patient_id_session_id_2ff02d8889", unique: true
+    t.index ["patient_id"], name: "index_patient_registration_statuses_on_patient_id"
+    t.index ["session_id"], name: "index_patient_registration_statuses_on_session_id"
     t.index ["status"], name: "index_patient_registration_statuses_on_status"
   end
 
@@ -1123,7 +1126,8 @@
   add_foreign_key "patient_changesets", "patients"
   add_foreign_key "patient_consent_statuses", "patients", on_delete: :cascade
   add_foreign_key "patient_consent_statuses", "programmes"
-  add_foreign_key "patient_registration_statuses", "patient_sessions", on_delete: :cascade
+  add_foreign_key "patient_registration_statuses", "patients", on_delete: :cascade
+  add_foreign_key "patient_registration_statuses", "sessions", on_delete: :cascade
   add_foreign_key "patient_sessions", "patients"
   add_foreign_key "patient_sessions", "sessions"
   add_foreign_key "patient_specific_directions", "patients"

spec/factories/patient_registration_statuses.rb

@@ -4,23 +4,27 @@
 #
 # Table name: patient_registration_statuses
 #
-#  id                 :bigint           not null, primary key
-#  status             :integer          default("unknown"), not null
-#  patient_session_id :bigint           not null
+#  id         :bigint           not null, primary key
+#  status     :integer          default("unknown"), not null
+#  patient_id :bigint           not null
+#  session_id :bigint           not null
 #
 # Indexes
 #
-#  index_patient_registration_statuses_on_patient_session_id  (patient_session_id) UNIQUE
-#  index_patient_registration_statuses_on_status              (status)
+#  idx_on_patient_id_session_id_2ff02d8889            (patient_id,session_id) UNIQUE
+#  index_patient_registration_statuses_on_patient_id  (patient_id)
+#  index_patient_registration_statuses_on_session_id  (session_id)
+#  index_patient_registration_statuses_on_status      (status)
 #
 # Foreign Keys
 #
-#  fk_rails_...  (patient_session_id => patient_sessions.id) ON DELETE => cascade
+#  fk_rails_...  (patient_id => patients.id) ON DELETE => cascade
+#  fk_rails_...  (session_id => sessions.id) ON DELETE => cascade
 #
 FactoryBot.define do
   factory :patient_registration_status, class: "Patient::RegistrationStatus" do
-    patient_session
-
+    patient
+    session
     traits_for_enum :status
   end
 end

spec/factories/patient_sessions.rb

@@ -43,27 +43,29 @@
     end
 
     trait :unknown_attendance do
-      registration_status do
-        association(:patient_registration_status, patient_session: instance)
-      end
-    end
-
-    trait :in_attendance do
-      registration_status do
-        association(
+      after(:create) do |patient_session|
+        create(
           :patient_registration_status,
-          :attending,
-          patient_session: instance
+          patient: patient_session.patient,
+          session: patient_session.session
         )
       end
+    end
 
+    trait :in_attendance do
       after(:create) do |patient_session|
         create(
           :session_attendance,
           :present,
           patient: patient_session.patient,
           session: patient_session.session
         )
+        create(
+          :patient_registration_status,
+          :attending,
+          patient: patient_session.patient,
+          session: patient_session.session
+        )
       end
     end
 

spec/factories/patients.rb

@@ -125,10 +125,7 @@
 
     after(:create) do |patient, evaluator|
       if evaluator.session
-        patient_session =
-          patient.patient_sessions.find_or_create_by!(
-            session: evaluator.session
-          )
+        PatientSession.find_or_create_by!(patient:, session: evaluator.session)
 
         if evaluator.in_attendance
           create(
@@ -137,7 +134,12 @@
             patient:,
             session: evaluator.session
           )
-          create(:patient_registration_status, :attending, patient_session:)
+          create(
+            :patient_registration_status,
+            :attending,
+            patient:,
+            session: evaluator.session
+          )
         end
       end
     end