# Ensures values are either the type you expect, a default value or nil.
#
# Virtus is built to handle data from a database where it's either well formed or nil. We need
# to tweak it's return values a little bit for it to handle form data. See https://github.com/solnic/virtus/issues/99.
module FormObject
  include Virtus

  module ClassMethods
    def attribute(name, type, opts = {})
      super(name, type, opts)
      define_method(name) do
        data = super()
        if data.is_a?(type)
          data
        elsif opts[:default]
          opts[:default].call
        else
          nil
        end
      end
    end
  end

  def self.included(descendant)
    super
    descendant.extend FormObject::ClassMethods
  end
end