combine similar validation methods

app/models/validations/sales/financial_validations.rb

@@ -105,41 +105,38 @@ module Validations::Sales::FinancialValidations
     end
   end
 
-  def validate_equity_less_than_staircase_difference(record)
+  def validate_staircase_difference(record)
     return unless record.equity && record.stairbought && record.stairowned
     return unless record.saledate && record.form.start_year_2024_or_later?
 
-    if record.equity > record.stairowned - record.stairbought
+    percentage_left = record.stairowned - record.stairbought - record.equity
+
+    if percentage_left.negative?
       formatted_equity = sprintf("%g", record.equity)
       joint_purchase_id = record.joint_purchase? ? "joint_purchase" : "not_joint_purchase"
+
       record.errors.add :equity, I18n.t("validations.sales.financial.equity.equity_over_stairowned_minus_stairbought.#{joint_purchase_id}", equity: formatted_equity, staircase_difference: record.stairowned - record.stairbought)
       record.errors.add :stairowned, I18n.t("validations.sales.financial.stairowned.equity_over_stairowned_minus_stairbought.#{joint_purchase_id}", equity: formatted_equity, staircase_difference: record.stairowned - record.stairbought)
       record.errors.add :stairbought, I18n.t("validations.sales.financial.stairbought.equity_over_stairowned_minus_stairbought.#{joint_purchase_id}", equity: formatted_equity, staircase_difference: record.stairowned - record.stairbought)
-    end
-  end
-
-  def validate_staircase_difference_enough_for_numstair(record)
-    return unless record.equity && record.stairbought && record.stairowned && record.numstair
-
-    percentage_left = record.stairowned - record.stairbought - record.equity
-    return if percentage_left.negative? # In this case we show the validate_equity_less_than_staircase_difference validation
-
-    previous_staircasing_transactions = record.numstair - 1
 
+    elsif record.numstair
       # We must use the lowest possible percentage for a staircasing transaction of any saletype, any year since 1980
       minimum_percentage_per_staircasing_transaction = 1
+      previous_staircasing_transactions = record.numstair - 1
 
       if percentage_left < previous_staircasing_transactions * minimum_percentage_per_staircasing_transaction
         equity_sum = sprintf("%g", record.stairowned - percentage_left + previous_staircasing_transactions * minimum_percentage_per_staircasing_transaction)
         formatted_equity = sprintf("%g", record.equity)
         formatted_stairbought = sprintf("%g", record.stairbought)
         formatted_stairowned = sprintf("%g", record.stairowned)
+
         record.errors.add :equity, I18n.t("validations.sales.financial.equity.more_than_stairowned_minus_stairbought_minus_prev_staircasing", equity: formatted_equity, bought: formatted_stairbought, numprevstair: previous_staircasing_transactions, equity_sum:, stair_total: formatted_stairowned)
         record.errors.add :stairowned, I18n.t("validations.sales.financial.stairowned.less_than_stairbought_plus_equity_plus_prev_staircasing", equity: formatted_equity, bought: formatted_stairbought, numprevstair: previous_staircasing_transactions, equity_sum:, stair_total: formatted_stairowned)
         record.errors.add :stairbought, I18n.t("validations.sales.financial.stairbought.more_than_stairowned_minus_equity_minus_prev_staircasing", equity: formatted_equity, bought: formatted_stairbought, numprevstair: previous_staircasing_transactions, equity_sum:, stair_total: formatted_stairowned)
         record.errors.add :numstair, I18n.t("validations.sales.financial.numstair.too_high_for_stairowned_minus_stairbought_minus_equity", equity: formatted_equity, bought: formatted_stairbought, numprevstair: previous_staircasing_transactions, equity_sum:, stair_total: formatted_stairowned)
       end
     end
+  end
 
 private