Replace pre-screening patient session foreign key

This replaces the foreign key association between pre-screenings and
patient sessions to instead link directly to the patient and the
session (via the date). 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, actually slightly
improved as pre-screening is only supposed to exist on the day it
happened, so now we link directly to the session date rather than the
overall session.

Jira-Issue: MAV-1819

Author: thomasleese

app/components/app_patient_session_record_component.rb

@@ -22,7 +22,7 @@ def render?
       (
         patient_session.registration_status&.attending? ||
           patient_session.registration_status&.completed? ||
-          !patient_session.session.requires_registration?
+          !session.requires_registration?
       )
   end
 
@@ -35,8 +35,14 @@ def render?
 
   def default_vaccinate_form
     pre_screening_confirmed = patient.pre_screenings.today.exists?(programme:)
+    session_date = session.session_dates.today.first
 
-    VaccinateForm.new(patient_session:, programme:, pre_screening_confirmed:)
+    VaccinateForm.new(
+      patient:,
+      session_date:,
+      programme:,
+      pre_screening_confirmed:
+    )
   end
 
   def heading

app/components/app_vaccinate_form_component.rb

@@ -11,8 +11,7 @@ def initialize(vaccinate_form)
 
   attr_reader :vaccinate_form
 
-  delegate :patient_session, :programme, to: :vaccinate_form
-  delegate :patient, :session, to: :patient_session
+  delegate :patient, :session, :programme, to: :vaccinate_form
   delegate :academic_year, to: :session
 
   def url

app/controllers/api/testing/teams_controller.rb

@@ -27,11 +27,7 @@ def destroy
 
         patient_ids = team.patients.pluck(:id)
 
-        patient_sessions = PatientSession.where(session: sessions)
-        log_destroy(PreScreening.where(patient_session: patient_sessions))
-        patient_sessions.in_batches { log_destroy(it) }
-
-        log_destroy(SessionDate.where(session: sessions))
+        log_destroy(PatientSession.where(session: sessions))
 
         log_destroy(AccessLogEntry.where(patient_id: patient_ids))
         log_destroy(ArchiveReason.where(patient_id: patient_ids))
@@ -41,11 +37,14 @@ def destroy
         # In local dev we can end up with NotifyLogEntries without a patient
         log_destroy(NotifyLogEntry.where(patient_id: nil))
         log_destroy(NotifyLogEntry.where(patient_id: patient_ids))
+        log_destroy(PreScreening.where(patient_id: patient_ids))
         log_destroy(SchoolMove.where(patient_id: patient_ids))
         log_destroy(SchoolMove.where(team:))
         log_destroy(SchoolMoveLogEntry.where(patient_id: patient_ids))
         log_destroy(VaccinationRecord.where(patient_id: patient_ids))
 
+        log_destroy(SessionDate.where(session: sessions))
+
         log_destroy(ConsentForm.where(team:))
         log_destroy(Consent.where(team:))
         log_destroy(Triage.where(team:))

app/controllers/patient_sessions/base_controller.rb

@@ -19,6 +19,10 @@ def set_session
       )
   end
 
+  def set_session_date
+    @session_date = @session.session_dates.find_by!(value: Date.current)
+  end
+
   def set_academic_year
     @academic_year = @session.academic_year
   end

app/controllers/patient_sessions/session_attendances_controller.rb

@@ -41,10 +41,6 @@ def update
 
   private
 
-  def set_session_date
-    @session_date = @session.session_dates.find_by!(value: Date.current)
-  end
-
   def set_session_attendance
     @session_attendance =
       authorize @patient_session

app/controllers/patient_sessions/vaccinations_controller.rb

@@ -5,6 +5,7 @@ class PatientSessions::VaccinationsController < PatientSessions::BaseController
   include VaccinationMailerConcern
 
   before_action :set_todays_batch
+  before_action :set_session_date
 
   after_action :verify_authorized
 
@@ -17,7 +18,8 @@ def create
     @vaccinate_form =
       VaccinateForm.new(
         current_user:,
-        patient_session: @patient_session,
+        patient: @patient,
+        session_date: @session_date,
         programme: @programme,
         todays_batch: @todays_batch,
         **vaccinate_form_params

app/forms/vaccinate_form.rb

@@ -4,7 +4,13 @@ class VaccinateForm
   include ActiveModel::Model
   include ActiveModel::Attributes
 
-  attr_accessor :patient_session, :programme, :current_user, :todays_batch
+  attr_accessor :patient,
+                :session_date,
+                :programme,
+                :current_user,
+                :todays_batch
+
+  delegate :session, to: :session_date
 
   attribute :identity_check_confirmed_by_other_name, :string
   attribute :identity_check_confirmed_by_other_relationship, :string
@@ -90,19 +96,19 @@ def save(draft_vaccination_record:)
       identity_check_confirmed_by_patient
     draft_vaccination_record.location_id =
       session.location_id unless session.generic_clinic?
-    draft_vaccination_record.patient_id = patient_session.patient_id
+    draft_vaccination_record.patient_id = patient.id
     draft_vaccination_record.performed_at = Time.current
     draft_vaccination_record.performed_by_user = current_user
     draft_vaccination_record.performed_ods_code = organisation.ods_code
     draft_vaccination_record.programme = programme
-    draft_vaccination_record.session_id = patient_session.session_id
+    draft_vaccination_record.session_id = session.id
 
     draft_vaccination_record.save # rubocop:disable Rails/SaveBang
   end
 
   private
 
-  delegate :organisation, :session, to: :patient_session
+  delegate :organisation, to: :session
 
   def administered? = vaccine_method != "none"
 
@@ -131,10 +137,11 @@ def delivery_method
 
   def pre_screening
     @pre_screening ||=
-      patient_session.pre_screenings.build(
+      patient.pre_screenings.build(
         notes: pre_screening_notes,
         performed_by: current_user,
-        programme:
+        programme:,
+        session_date:
       )
   end
 end

app/lib/patient_merger.rb

@@ -40,6 +40,10 @@ def call
         patient_id: patient_to_keep.id
       )
 
+      patient_to_destroy.pre_screenings.update_all(
+        patient_id: patient_to_keep.id
+      )
+
       patient_to_destroy.school_moves.find_each do |school_move|
         if patient_to_keep.school_moves.exists?(
              home_educated: school_move.home_educated,
@@ -78,18 +82,12 @@ def call
       end
 
       patient_to_destroy.patient_sessions.each do |patient_session|
-        if (
-             existing_patient_session =
-               patient_to_keep.patient_sessions.find_by(
-                 session_id: patient_session.session_id
-               )
+        if patient_to_keep.patient_sessions.exists?(
+             session_id: patient_session.session_id
            )
-          patient_session.pre_screenings.update_all(
-            patient_session_id: existing_patient_session.id
-          )
-        else
-          patient_session.update!(patient: patient_to_keep)
+          next
         end
+        patient_session.update!(patient: patient_to_keep)
       end
 
       PatientSession.where(patient: patient_to_destroy).destroy_all

app/models/patient.rb

@@ -70,6 +70,7 @@ class Patient < ApplicationRecord
   has_many :parent_relationships, -> { order(:created_at) }
   has_many :patient_sessions
   has_many :pds_search_results
+  has_many :pre_screenings
   has_many :school_move_log_entries
   has_many :school_moves
   has_many :session_notifications
@@ -81,7 +82,6 @@ class Patient < ApplicationRecord
   has_many :gillick_assessments
   has_many :parents, through: :parent_relationships
   has_many :patient_specific_directions
-  has_many :pre_screenings, through: :patient_sessions
   has_many :session_attendances, through: :patient_sessions
   has_many :sessions, through: :patient_sessions
   has_many :teams, -> { distinct }, through: :sessions

app/models/patient_session.rb

@@ -44,7 +44,6 @@ class PatientSession < ApplicationRecord
   belongs_to :patient
   belongs_to :session
 
-  has_many :pre_screenings
   has_many :session_attendances, dependent: :destroy
   has_one :registration_status
 
@@ -64,6 +63,10 @@ class PatientSession < ApplicationRecord
           through: :patient,
           source: :notes
 
+  has_many :pre_screenings,
+           -> { where(patient_id: it.patient_id) },
+           through: :session
+
   has_many :session_notifications,
            -> { where(session_id: it.session_id) },
            through: :patient