Move selectable_subject_symbols into the journey.

There was a lot of duplicated business rules in this method.
We were explicity checking for `nqt_in_academic_year_after_itt`, and if
it was absent we were falling back to only the lup subjects. The ECP
policy is ineligible for non `nqt_in_academic_year_after_itt` claims so
it will be filtered out when we check for
`potentially_still_eligible_policies`.
We returned an empty array if the `current_academic_year` was outside
the lup policy dates, however the LUP#subject_symbols method already
returns an empty array of available subjects for years outside the
policy.

There's some weirdness in the
`AdditionalPaymentsForTeaching.selectable_subject_symbols` method. If
we're dealing with a trainee teacher, we return a hard coded list of
subjects, however trainee teachers won't be eligible as the
`EligibilityCheckable#common_ineligible_attributes?` checks if the
claimant is a trainee teacher, and is thus ineligible. It seems weird to
return a list of subjects if the claimant is ineligible. This was the
existing behaviour so I've kept it in place but this likely needs
revisiting.

app/forms/journeys/additional_payments_for_teaching/eligible_itt_subject_form.rb

@@ -50,7 +50,7 @@ def chemistry_or_physics_available?
 
       def subject_symbols
         @subject_symbols ||=
-          JourneySubjectEligibilityChecker.selectable_subject_symbols(answers)
+          AdditionalPaymentsForTeaching.selectable_subject_symbols(journey_session)
       end
 
       def save

app/models/academic_year.rb

@@ -107,8 +107,12 @@ def eql?(other)
     to_s == other.to_s
   end
 
+  def none?
+    [start_year, end_year].include? nil
+  end
+
   def to_s(format = :default)
-    return "None" if [start_year, end_year].include? nil
+    return "None" if none?
 
     if format == :long
       "#{start_year} to #{end_year}"

app/models/concerns/eligibility_checkable.rb

@@ -49,7 +49,15 @@ def trainee_teacher?
   private
 
   def common_ineligible_attributes?
-    [indicated_ineligible_school?, trainee_teacher?, supply_teacher_lacking_either_long_contract_or_direct_employment?, poor_performance?, no_selectable_subjects?, ineligible_cohort?, insufficient_teaching?].any?
+    [
+      indicated_ineligible_school?,
+      trainee_teacher?,
+      supply_teacher_lacking_either_long_contract_or_direct_employment?,
+      poor_performance?,
+      no_selectable_subjects?,
+      ineligible_cohort?,
+      insufficient_teaching?
+    ].any?
   end
 
   def indicated_ineligible_school?
@@ -65,12 +73,13 @@ def poor_performance?
   end
 
   def no_selectable_subjects?
-    args = {claim_year: claim_year, itt_year: itt_academic_year}
-
-    if args.values.any?(&:blank?)
+    if claim_year.blank? || itt_academic_year.blank?
       false
     else
-      JourneySubjectEligibilityChecker.new(**args).current_and_future_subject_symbols(policy).empty?
+      policy.current_and_future_subject_symbols(
+        claim_year: claim_year,
+        itt_year: itt_academic_year
+      ).empty?
     end
   end
 

app/models/journeys/additional_payments_for_teaching.rb

@@ -42,5 +42,25 @@ def set_a_reminder?(itt_academic_year:, policy:)
     def requires_student_loan_details?
       true
     end
+
+    def selectable_subject_symbols(journey_session)
+      return [] if journey_session.answers.itt_academic_year&.none?
+
+      if journey_session.answers.nqt_in_academic_year_after_itt
+        EligibilityChecker.new(journey_session: journey_session)
+          .potentially_still_eligible.map do |policy|
+            policy.current_and_future_subject_symbols(
+              claim_year: journey_session.answers.policy_year,
+              itt_year: journey_session.answers.itt_academic_year
+            )
+          end.flatten.uniq
+      elsif journey_session.answers.policy_year.in?(EligibilityCheckable::COMBINED_ECP_AND_LUP_POLICY_YEARS_BEFORE_FINAL_YEAR)
+        # they get the standard, unchanging LUP subject set because they won't have qualified in time for ECP by 2022/2023
+        # and they won't have given an ITT year
+        Policies::LevellingUpPremiumPayments.fixed_subject_symbols
+      else
+        []
+      end
+    end
   end
 end

app/models/journeys/additional_payments_for_teaching/answers_presenter.rb

@@ -157,10 +157,11 @@ def itt_academic_year
 
       def text_for_subject_answer
         policy = eligibility.policy
-        subjects = JourneySubjectEligibilityChecker.new(
+
+        subjects = policy.current_and_future_subject_symbols(
           claim_year: Journeys.for_policy(policy).configuration.current_academic_year,
           itt_year: journey_session.answers.itt_academic_year
-        ).current_and_future_subject_symbols(policy)
+        )
 
         if subjects.many?
           t("additional_payments.forms.eligible_itt_subject.answers.#{journey_session.answers.eligible_itt_subject}")
@@ -173,7 +174,10 @@ def text_for_subject_answer
       private
 
       def subject_symbols
-        @subject_symbols ||= JourneySubjectEligibilityChecker.current_and_future_subject_symbols(answers)
+        @subject_symbols ||= answers.policy.subject_symbols(
+          claim_year: answers.policy_year,
+          itt_year: answers.itt_academic_year
+        )
       end
 
       def claim_submission_form

app/models/journeys/eligibility_checker.rb

@@ -63,6 +63,14 @@ def policies_eligible_now_and_sorted
       policies_eligible_now_with_award_amount_and_sorted.map { |policy_with_award_amount| policy_with_award_amount.policy }
     end
 
+    def potentially_still_eligible
+      policies.select do |policy|
+        policy::PolicyEligibilityChecker.new(
+          answers: @journey_session.answers
+        ).status != :ineligible
+      end
+    end
+
     private
 
     def policies_eligible_now_with_award_amount

app/models/journeys/page_sequence.rb

@@ -104,7 +104,7 @@ def handle_trainee_teacher
           @journey_session.answers.policy_year.in?(EligibilityCheckable::COMBINED_ECP_AND_LUP_POLICY_YEARS_BEFORE_FINAL_YEAR) ? "eligible-itt-subject" : "ineligible"
         end
       when "eligible-itt-subject"
-        if answers.eligible_itt_subject.to_sym.in? JourneySubjectEligibilityChecker.fixed_lup_subject_symbols
+        if answers.eligible_itt_subject.to_sym.in? Policies::LevellingUpPremiumPayments.fixed_subject_symbols
           "future-eligibility"
         else
           "eligible-degree-subject"

app/models/policies/early_career_payments.rb

@@ -110,6 +110,29 @@ def auto_check_student_loan_plan_task?
       true
     end
 
+    def current_subject_symbols(claim_year:, itt_year:)
+      subject_symbols(claim_year: claim_year, itt_year: itt_year)
+    end
+
+    def future_subject_symbols(claim_year:, itt_year:)
+      future_years(claim_year).flat_map do |year|
+        subject_symbols(claim_year: year, itt_year: itt_year)
+      end
+    end
+
+    def current_and_future_subject_symbols(claim_year:, itt_year:)
+      [
+        *current_subject_symbols(
+          claim_year: claim_year,
+          itt_year: itt_year
+        ),
+        *future_subject_symbols(
+          claim_year: claim_year,
+          itt_year: itt_year
+        )
+      ].uniq
+    end
+
     def subject_symbols(claim_year:, itt_year:)
       case AcademicYear.wrap(claim_year)
       when AcademicYear.new(2022), AcademicYear.new(2024)
@@ -134,5 +157,17 @@ def subject_symbols(claim_year:, itt_year:)
         []
       end
     end
+
+    def current_and_future_years(year)
+      fail "year before policy start year" if year < POLICY_START_YEAR
+
+      [year] + future_years(year)
+    end
+
+    def future_years(year)
+      fail "year before policy start year" if year < POLICY_START_YEAR
+
+      year + 1..POLICY_END_YEAR
+    end
   end
 end

app/models/policies/early_career_payments/dqt_record.rb

@@ -49,10 +49,11 @@ def eligible_itt_subject_for_claim
 
         return :none_of_the_above if itt_subject_groups.empty? || !year
 
-        itt_subject_checker = JourneySubjectEligibilityChecker.new(claim_year: current_academic_year, itt_year: year)
-
         itt_subject_groups.delete_if do |itt_subject_group|
-          !itt_subject_group.in?(itt_subject_checker.current_and_future_subject_symbols(EarlyCareerPayments))
+          EarlyCareerPayments.current_and_future_subject_symbols(
+            claim_year: current_academic_year,
+            itt_year: year
+          ).exclude?(itt_subject_group)
         end.first.to_sym
       rescue # JourneySubjectEligibilityChecker can also raise an exception if itt_year is out of eligible range
         :none_of_the_above

app/models/policies/early_career_payments/policy_eligibility_checker.rb

@@ -47,8 +47,10 @@ def itt_subject_eligible_now?
         return false if itt_subject.blank?
         return false if itt_subject_none_of_the_above?
 
-        itt_subject_checker = JourneySubjectEligibilityChecker.new(claim_year: claim_year, itt_year: itt_academic_year)
-        itt_subject.to_sym.in?(itt_subject_checker.current_subject_symbols(policy))
+        EarlyCareerPayments.current_subject_symbols(
+          claim_year: claim_year,
+          itt_year: itt_academic_year
+        ).include?(itt_subject.to_sym)
       end
 
       def specific_ineligible_attributes?
@@ -60,8 +62,10 @@ def itt_subject_ineligible_now_and_in_the_future?
         return false if itt_subject.blank?
         return true if itt_subject_none_of_the_above?
 
-        itt_subject_checker = JourneySubjectEligibilityChecker.new(claim_year: claim_year, itt_year: itt_academic_year)
-        !itt_subject.to_sym.in?(itt_subject_checker.current_and_future_subject_symbols(policy))
+        EarlyCareerPayments.current_and_future_subject_symbols(
+          claim_year: claim_year,
+          itt_year: itt_academic_year
+        ).exclude?(itt_subject.to_sym)
       end
 
       def specific_eligible_later_attributes?
@@ -73,8 +77,10 @@ def itt_subject_eligible_later?
         return false if itt_subject.blank?
         return false if itt_subject_none_of_the_above?
 
-        itt_subject_checker = JourneySubjectEligibilityChecker.new(claim_year: claim_year, itt_year: itt_academic_year)
-        itt_subject.to_sym.in?(itt_subject_checker.future_subject_symbols(policy))
+        EarlyCareerPayments.future_subject_symbols(
+          claim_year: claim_year,
+          itt_year: itt_academic_year
+        ).include?(itt_subject.to_sym)
       end
 
       # TODO: Is this used anywhere?
@@ -94,9 +100,10 @@ def itt_subject_other_than_those_eligible_now_or_in_the_future?
           # can still rule some out
           itt_subject_none_of_the_above?
         else
-          itt_subject_checker = JourneySubjectEligibilityChecker.new(**args)
-          itt_subject_symbol = itt_subject.to_sym
-          !itt_subject_symbol.in?(itt_subject_checker.current_and_future_subject_symbols(policy))
+          EarlyCareerPayments.current_and_future_subject_symbols(
+            claim_year: claim_year,
+            itt_year: itt_academic_year
+          ).exclude?(itt_subject_symbol)
         end
       end
     end

app/models/policies/levelling_up_premium_payments.rb

@@ -100,16 +100,55 @@ def auto_check_student_loan_plan_task?
       true
     end
 
+    def current_subject_symbols(claim_year:, itt_year:)
+      subject_symbols(claim_year: claim_year, itt_year: itt_year)
+    end
+
+    def future_subject_symbols(claim_year:, itt_year:)
+      future_years(claim_year).flat_map do |year|
+        subject_symbols(claim_year: year, itt_year: itt_year)
+      end
+    end
+
+    def current_and_future_subject_symbols(claim_year:, itt_year:)
+      [
+        *current_subject_symbols(
+          claim_year: claim_year,
+          itt_year: itt_year
+        ),
+        *future_subject_symbols(
+          claim_year: claim_year,
+          itt_year: itt_year
+        )
+      ].uniq
+    end
+
+    def fixed_subject_symbols
+      [:chemistry, :computing, :mathematics, :physics]
+    end
+
     def subject_symbols(claim_year:, itt_year:)
       return [] unless (POLICY_START_YEAR..POLICY_END_YEAR).cover?(claim_year)
 
       previous_five_years = (claim_year - 5)...claim_year
 
       if previous_five_years.cover?(itt_year)
-        [:chemistry, :computing, :mathematics, :physics]
+        fixed_subject_symbols
       else
         []
       end
     end
+
+    def current_and_future_years(year)
+      fail "year before policy start year" if year < POLICY_START_YEAR
+
+      [year] + future_years(year)
+    end
+
+    def future_years(year)
+      fail "year before policy start year" if year < POLICY_START_YEAR
+
+      year + 1..POLICY_END_YEAR
+    end
   end
 end

app/models/policies/levelling_up_premium_payments/policy_eligibility_checker.rb

@@ -22,7 +22,7 @@ def indicated_ineligible_itt_subject?
 
         if args.values.any?(&:blank?)
           # trainee teacher who won't have given their ITT year
-          eligible_itt_subject.present? && !eligible_itt_subject.to_sym.in?(JourneySubjectEligibilityChecker.fixed_lup_subject_symbols)
+          eligible_itt_subject.present? && !eligible_itt_subject.to_sym.in?(policy.fixed_subject_symbols)
         else
           itt_subject_checker = JourneySubjectEligibilityChecker.new(**args)
           eligible_itt_subject.present? && !eligible_itt_subject.to_sym.in?(itt_subject_checker.current_subject_symbols(policy))

lib/ineligibility_reason_checker.rb

@@ -154,10 +154,10 @@ def subject_invalid_for_ecp?
   end
 
   def ecp_subject_options
-    JourneySubjectEligibilityChecker.new(
+    Policies::EarlyCareerPayments.current_and_future_subject_symbols(
       claim_year: @answers.policy_year,
       itt_year: @answers.itt_academic_year
-    ).current_and_future_subject_symbols(Policies::EarlyCareerPayments)
+    )
   end
 
   def bad_itt_year_for_ecp?

lib/journey_subject_eligibility_checker.rb

@@ -41,27 +41,14 @@ def self.selectable_itt_years_for_claim_year(claim_year)
     (AcademicYear.new(claim_year - 5)...AcademicYear.new(claim_year)).to_a
   end
 
-  def self.current_and_future_subject_symbols(answers)
-    return [] if answers.itt_academic_year.blank?
-
-    if answers.nqt_in_academic_year_after_itt
-      JourneySubjectEligibilityChecker.new(claim_year: answers.policy_year, itt_year: answers.itt_academic_year).current_and_future_subject_symbols(answers.policy)
-    elsif answers.policy_year.in?(EligibilityCheckable::COMBINED_ECP_AND_LUP_POLICY_YEARS_BEFORE_FINAL_YEAR)
-      # they get the standard, unchanging LUP subject set because they won't have qualified in time for ECP by 2022/2023
-      # and they won't have given an ITT year
-      JourneySubjectEligibilityChecker.fixed_lup_subject_symbols
-    else
-      []
-    end.sort
-  end
-
   # Ideally we wouldn't have this method at all. Unfortunately it was hardcoded like
   # this before we realised trainee teachers weren't as special a case as we
   # thought.
   def self.fixed_lup_subject_symbols
     [:chemistry, :computing, :mathematics, :physics]
   end
 
+  # FIXME RL - should be able to delete all the methods using this
   def current_and_future_subject_symbols(policy)
     (current_subject_symbols(policy) + future_subject_symbols(policy)).uniq
   end
@@ -70,7 +57,11 @@ def current_subject_symbols(policy)
     if none_of_the_above_or_blank?(@itt_year)
       []
     else
-      subject_symbols(policy: policy, claim_year: @claim_year, itt_year: @itt_year)
+      subject_symbols(
+        policy: policy,
+        claim_year: @claim_year,
+        itt_year: @itt_year
+      )
     end
   end
 
@@ -92,6 +83,7 @@ def selectable_subject_symbols(answers)
 
   private
 
+  # Move this
   def potentially_still_eligible_policies(answers)
     Journeys::AdditionalPaymentsForTeaching::POLICIES.select do |policy|
       policy::PolicyEligibilityChecker.new(answers: answers).status != :ineligible