Add validation for reactivation date before deactivation date

app/models/location.rb

@@ -426,6 +426,7 @@ class Location < ApplicationRecord
   def reactivation_date_errors
     return unless @run_reactivation_validations
 
+    recent_deactivation = location_deactivation_periods.deactivations_without_reactivation.first
     if reactivation_date.blank?
       if reactivation_date_type.blank?
         errors.add(:reactivation_date_type, message: I18n.t("validations.location.toggle_date.not_selected"))
@@ -434,8 +435,10 @@ class Location < ApplicationRecord
       end
     else
       collection_start_date = FormHandler.instance.current_collection_start_date
-      unless reactivation_date.between?(collection_start_date, Time.zone.local(2200, 1, 1))
+      if !reactivation_date.between?(collection_start_date, Time.zone.local(2200, 1, 1))
         errors.add(:reactivation_date, message: I18n.t("validations.location.toggle_date.out_of_range", date: collection_start_date.to_formatted_s(:govuk_date)))
+      elsif reactivation_date < recent_deactivation.deactivation_date
+        errors.add(:reactivation_date, message: I18n.t("validations.location.reactivation.before_deactivation", date: recent_deactivation.deactivation_date.to_formatted_s(:govuk_date)))
       end
     end
   end

config/locales/en.yml

@@ -323,6 +323,8 @@ en:
         not_selected: "Select one of the options"
         invalid: "Enter a valid day, month and year"
         out_of_range: "The date must be on or after the %{date}"
+      reactivation:
+        before_deactivation: "This location was deactivated on %{date}\nThe reactivation date must be on or after deactivation date"
 
   soft_validations:
     net_income:

spec/requests/locations_controller_spec.rb

@@ -1478,7 +1478,7 @@ RSpec.describe LocationsController, type: :request do
       let(:user) { FactoryBot.create(:user, :data_coordinator) }
       let!(:scheme) { FactoryBot.create(:scheme, owning_organisation: user.organisation) }
       let!(:location) { FactoryBot.create(:location, scheme:) }
-      let(:deactivation_date) { Time.zone.local(2022, 10, 10) }
+      let(:deactivation_date) { Time.zone.local(2022, 4, 1) }
       let(:startdate) { Time.utc(2022, 10, 11) }
 
       before do
@@ -1594,6 +1594,16 @@ RSpec.describe LocationsController, type: :request do
           expect(page).to have_content(I18n.t("validations.location.toggle_date.invalid"))
         end
       end
+
+      context "when the reactivation date is before deactivation date" do
+        let(:deactivation_date) { Time.zone.local(2022, 10, 10) }
+        let(:params) { { location: { reactivation_date_type: "other", "reactivation_date(3i)": "8", "reactivation_date(2i)": "9", "reactivation_date(1i)": "2022" } } }
+
+        it "displays page with an error message" do
+          expect(response).to have_http_status(:unprocessable_entity)
+          expect(page).to have_content(I18n.t("validations.location.reactivation.before_deactivation", date: "10 October 2022"))
+        end
+      end
     end
   end
 end