redjazz96/nova

require 'nova/common/metadata/data'
require 'nova/common/metadata/options'

module Nova
  module Common

    # Manages the metadata, such as required options, ruby versions,
    # required platforms/versions, etc.
    module Metadata

      # Class methods.
      module ClassMethods

        # @overload metadata(&block)
        #   Runs the metadata block in a metadata instance, and then
        #   sets the metadata information for this star.
        #
        #   @yield [Data]
        #   @return [Data]
        # @overload metadata
        #   Returns the metadata for this star.
        #
        #   @return [Data]
        def metadata(&block)
          if block_given?
            data = Data.new
            data.instance_exec data, &block
            @metadata = data
          else
            @metadata ||= Data.new
          end
        end

      end

      # Instance methods.
      module InstanceMethods

        # Handles validation for the metadata.
        def initialize(*)
          @meta = self.class.metadata
          @meta.validate! remote
        end

        # Sets the options, validating them.
        def options=(options)
          options = Options.new(options)
          @meta.validate_options! options
          @options = options
        end

      end

      # Called when {Metadata} is included.  Extends what included
      # it by {ClassMethods}, and includes {InstanceMethods}.
      #
      # @param receiver [Object]
      # @return [void]
      # @api private
      def self.included(receiver)
        receiver.extend         ClassMethods
        receiver.send :include, InstanceMethods
      end
    end

  end
end