module HasRandomToken
  extend ActiveSupport::Concern

  module ClassMethods
    def has_random_token(attribute: :token, unique: false, length: 32)
      require 'securerandom'

      define_method("regenerate_#{attribute}") { update! attribute => self.class.generate_random_token(attribute, unique, length) }
      before_create { self.send("#{attribute}=", self.class.generate_random_token(attribute, unique, length)) unless self.send("#{attribute}?")}
    end

    def generate_random_token(attribute, unique, length)
    	begin
	      token = SecureRandom.base64(length)[0 .. length - 1]
	    end while unique && self.exists?(attribute => token)

    	return token
    end

  end
end

ActiveRecord::Base.send :include, HasRandomToken