class User < ApplicationRecord
  validates_with UserBirthZalupaValidator
end

class UserBirthZalupaValidator < ActiveModel::Validator
  def validate(record)
    begin
      birth = Date.parse(record.birth_date.to_s)
      record.errors.add(:base, "zlpa") unless birth.between?(start_date, end_date)
    rescue StandardError => e
      Rails.logger.error("Full zlpa: #{e.inspect}")
    end
  end

  def start_date
    Date.new(1900,1,1)
  end

  def end_date
    Time.zone.today
  end
end