feat: add validation behaviour

app/models/validations/sales/financial_validations.rb

@@ -70,6 +70,27 @@ module Validations::Sales::FinancialValidations
     end
   end
 
+  def validate_equity_in_range_for_year_and_type(record)
+    return unless record.type && record.equity && record.collection_start_year
+
+    if record.collection_start_year == 2022
+      ranges = EQUITY_RANGES_FOR_TYPES_BY_COLLECTION_START_YEAR[2022]
+    elsif record.collection_start_year >= 2023
+      ranges = EQUITY_RANGES_FOR_TYPES_BY_COLLECTION_START_YEAR[2023]
+    end
+
+    if ranges.key?(record.type)
+      range = ranges[record.type]
+      if record.equity < range["min"]
+        record.errors.add :type, I18n.t("validations.financial.equity.under_min", min_equity: range["min"])
+        record.errors.add :equity, I18n.t("validations.financial.equity.under_min", min_equity: range["min"])
+      elsif record.equity > range["max"]
+        record.errors.add :type, I18n.t("validations.financial.equity.over_max")
+        record.errors.add :equity, I18n.t("validations.financial.equity.over_max")
+      end
+    end
+  end
+
 private
 
   def is_relationship_child?(relationship)
@@ -79,4 +100,26 @@ private
   def is_economic_status_child?(economic_status)
     economic_status == 9
   end
+
+  EQUITY_RANGES_FOR_TYPES_BY_COLLECTION_START_YEAR = {
+    2022 => {
+      2 => { "min" => 25, "max" => 75 },
+      30 => { "min" => 10, "max" => 75 },
+      18 => { "min" => 25, "max" => 75 },
+      16 => { "min" => 10, "max" => 75 },
+      24 => { "min" => 25, "max" => 75 },
+      # 28 => ranges don't apply
+      31 => { "min" => 0, "max" => 75 },
+    },
+    2023 => {
+      2 => { "min" => 10, "max" => 75 },
+      30 => { "min" => 25, "max" => 75 },
+      18 => { "min" => 25, "max" => 75 },
+      16 => { "min" => 10, "max" => 75 },
+      24 => { "min" => 25, "max" => 75 },
+      # 28 => ranges don't apply
+      31 => { "min" => 0, "max" => 75 },
+      32 => { "min" => 0, "max" => 75 },
+    },
+  }.freeze
 end

config/locales/en.yml

@@ -297,6 +297,9 @@ en:
       staircasing:
         percentage_bought_must_be_greater_than_percentage_owned: "Total percentage buyer now owns must be more than percentage bought in this transaction"
         older_person_percentage_owned_maximum_75: "Percentage cannot be above 75% under Older Person's Shared Ownership"
+      equity:
+        under_min: "The minimum initial equity stake for this type of shared ownership sale is %{min_equity}%"
+        over_max: "The maximum initial equity stake is 75%"
 
     household:
       reasonpref: