module Dsc
  module Mash
    class << self
      DEFAULT_PROC = lambda do |hash, key|
        raise UndefinedAttribute,
          "Attribute #{key} is not defined in the config file (current hash: #{hash.inspect})."
      end

      def new(source)
        Hashie::Mash.new(source).tap do |hash|
          recursively_freeze(hash)
        end
      end

      private

      def recursively_freeze(object)
        case object
          when Array
            object.each { |obj| recursively_freeze(obj) }
          when Hash
            object.default_proc = DEFAULT_PROC
            recursively_freeze(object.values)
        end
      end
    end
  end
end