Restrict shown answer options based on already answered questions

app/models/form/setup/questions/created_by_id.rb

@@ -18,6 +18,13 @@ class Form::Setup::Questions::CreatedById < ::Form::Question
     end
   end
 
+  def displayed_answer_options(case_log)
+    return answer_options unless case_log.owning_organisation
+
+    user_ids = case_log.owning_organisation.users.pluck(:id) + [""]
+    answer_options.select { |k, _v| user_ids.include?(k) }
+  end
+
   def label_from_value(value)
     return unless value
 

app/models/form/setup/questions/owning_organisation_id.rb

@@ -18,6 +18,13 @@ class Form::Setup::Questions::OwningOrganisationId < ::Form::Question
     end
   end
 
+  def displayed_answer_options(case_log)
+    return answer_options unless case_log.created_by
+
+    ids = ["", case_log.created_by.organisation.id]
+    answer_options.select { |k, _v| ids.include?(k) }
+  end
+
   def label_from_value(value)
     return unless value
 

spec/models/form/setup/questions/created_by_id_spec.rb

@@ -73,4 +73,18 @@ RSpec.describe Form::Setup::Questions::CreatedById, type: :model do
       expect(question.hidden_in_check_answers).to be true
     end
   end
+
+  context "when the owning organisation is already set" do
+    let(:case_log) { FactoryBot.create(:case_log, owning_organisation: user_2.organisation) }
+    let(:expected_answer_options) do
+      {
+        "" => "Select an option",
+        user_2.id => user_2.name,
+      }
+    end
+
+    it "only displays users that belong to that organisation" do
+      expect(question.displayed_answer_options(case_log)).to eq(expected_answer_options)
+    end
+  end
 end

spec/models/form/setup/questions/owning_organisation_id_spec.rb

@@ -73,4 +73,19 @@ RSpec.describe Form::Setup::Questions::OwningOrganisationId, type: :model do
       expect(question.hidden_in_check_answers).to be true
     end
   end
+
+  context "when the user is already set" do
+    let(:user) { FactoryBot.create(:user, organisation: organisation_2) }
+    let(:case_log) { FactoryBot.create(:case_log, created_by: user) }
+    let(:expected_answer_options) do
+      {
+        "" => "Select an option",
+        organisation_2.id => organisation_2.name,
+      }
+    end
+
+    it "only displays users that belong to that organisation" do
+      expect(question.displayed_answer_options(case_log)).to eq(expected_answer_options)
+    end
+  end
 end