base_validator.rb

# Classe base de validações auxiliares
class BaseValidator < SimpleDelegator
  include ActiveModel::Model
  include ActiveModel::Validations
  
  def build_error_list(prefix, list, indexes = nil)
    error_list = list.each_with_index.map do |item, i|
      index = coalesce_index(item, i, indexes)
      key = [prefix, index].compact.join '.'

      [key, item.errors.messages] if item.errors.any?
    end.compact
    Hash[error_list]
  end

  private

  def coalesce_index(item, index, indexes)
    return indexes[i] if indexes.present?

    item.respond_to?(:index) ? item.index : index
  end

  class << self
    def i18n_scope
      const_defined?(:MODEL) ? self::MODEL.i18n_scope : super
    end

    def model_name
      const_defined?(:MODEL) ? self::MODEL.model_name : super
    end
  end
end