openfoodnetwork/app/models/concerns/stock_settings_override_validation.rb

module StockSettingsOverrideValidation
  extend ActiveSupport::Concern

  included do
    before_validation :require_compatible_on_demand_and_count_on_hand
  end

  def require_compatible_on_demand_and_count_on_hand
    disallow_count_on_hand_if_using_producer_stock_settings
    disallow_count_on_hand_if_on_demand
    require_count_on_hand_if_limited_stock
  end

  def disallow_count_on_hand_if_using_producer_stock_settings
    return unless on_demand.nil? && count_on_hand.present?

    error_message = I18n.t("count_on_hand.using_producer_stock_settings_but_count_on_hand_set",
                           scope: i18n_scope_for_stock_settings_override_validation_error)
    errors.add(:count_on_hand, error_message)
  end

  def disallow_count_on_hand_if_on_demand
    return unless on_demand? && count_on_hand.present?

    error_message = I18n.t("count_on_hand.on_demand_but_count_on_hand_set",
                           scope: i18n_scope_for_stock_settings_override_validation_error)
    errors.add(:count_on_hand, error_message)
  end

  def require_count_on_hand_if_limited_stock
    return unless on_demand == false && count_on_hand.blank?

    error_message = I18n.t("count_on_hand.limited_stock_but_no_count_on_hand",
                           scope: i18n_scope_for_stock_settings_override_validation_error)
    errors.add(:count_on_hand, error_message)
  end

  def i18n_scope_for_stock_settings_override_validation_error
    "activerecord.errors.models.#{self.class.name.underscore}"
  end
end