validate staircasing dates

app/models/validations/sales/sale_information_validations.rb

@@ -41,6 +41,29 @@ module Validations::Sales::SaleInformationValidations
     if record.initialpurchase < Time.zone.local(1980, 1, 1)
       record.errors.add :initialpurchase, I18n.t("validations.sales.sale_information.initialpurchase.must_be_after_1980")
     end
+
+    if record.initialpurchase > record.saledate
+      record.errors.add :initialpurchase, I18n.t("validations.sales.sale_information.initialpurchase.must_be_before_saledate")
+      record.errors.add :saledate, I18n.t("validations.sales.sale_information.saledate.must_be_after_initial_purchase_date")
+    end
+  end
+
+  def validate_staircasing_last_transaction_date(record)
+    return unless record.lasttransaction
+
+    if record.lasttransaction < Time.zone.local(1980, 1, 1)
+      record.errors.add :lasttransaction, I18n.t("validations.sales.sale_information.lasttransaction.must_be_after_1980")
+    end
+
+    if record.lasttransaction > record.saledate
+      record.errors.add :lasttransaction, I18n.t("validations.sales.sale_information.lasttransaction.must_be_before_saledate")
+      record.errors.add :saledate, I18n.t("validations.sales.sale_information.saledate.must_be_after_last_transaction_date")
+    end
+
+    if record.initialpurchase.present? && record.lasttransaction < record.initialpurchase
+       record.errors.add :initialpurchase, I18n.t("validations.sales.sale_information.initialpurchase.must_be_before_last_transaction")
+       record.errors.add :lasttransaction, I18n.t("validations.sales.sale_information.lasttransaction.must_be_after_initial_purchase")
+    end
   end
 
   def validate_previous_property_unit_type(record)

config/locales/validations/sales/sale_information.en.yml

@@ -16,11 +16,20 @@ en:
           must_be_after_exdate: "Sale completion date must be after contract exchange date."
           must_be_less_than_1_year_from_exdate: "Sale completion date must be less than 1 year after contract exchange date."
           mortgage_used_year: "You must answer either ‘yes’ or ‘no’ to the question ‘was a mortgage used’ for the selected year."
+          must_be_after_initial_purchase_date: "Sale completion date for a staircasing transaction must be after the date of the initial purchase of a share."
+          must_be_after_last_transaction_date: "Sale completion date must be after the date of the last staircasing transaction."
+
         exdate:
           must_be_before_saledate: "Contract exchange date must be before sale completion date."
           must_be_less_than_1_year_from_saledate: "Contract exchange date must be less than 1 year before sale completion date."
         initialpurchase:
           must_be_after_1980: "The initial purchase date must be after January 1, 1980."
+          must_be_before_last_transaction: "The initial purchase date must be before the last staircasing transaction date."
+          must_be_before_saledate: "The initial purchase date must be before the date of this sale."
+        lasttransaction:
+          must_be_after_1980: "The last staircasing transaction date must be after January 1, 1980."
+          must_be_after_initial_purchase: "The last staircasing transaction date must be after the initial purchase date."
+          must_be_before_saledate: "The last staircasing transaction date must be before the date of this sale."
         fromprop:
           previous_property_type_bedsit: "A bedsit cannot have more than 1 bedroom."
         frombeds: