# A message is what is sent when you invoke a method. Args and stuff are packed up in to a Message
# and the Message is sent to the receiver.

# Part of the housekeeping (see attributes) makes messages a double linked list (next_message and
#  caller) , and maybe surprisingly this means that we can create all messages at runtime
# and link them up and never have to touch that list again.
# All the args and receiver data changes, but the list of messages stays constant.

module Parfait
  class Message < Object
    attributes [:next_message , :frame, :caller]
    attributes [:receiver ,  :return_address , :return_value , :name]

    def initialize next_m
      self.next_message = next_m
      self.frame = Frame.new()
      self.caller = nil
      super()
    end


    def set_caller caller
      self.caller = caller
    end

    def get_type_for(name)
      index = @layout.get_index(name)
      get_at(index)
    end

    # def __send
    #   typ = get_type_for( :receiver )
    #   # TODO: this will obviously be recoded as case, once that is done :-)
    #   # depending on value type get method
    #   if( typ == Integer )
    #     method = Integer.get_method @method_name
    #   else
    #     if( typ != ObjectReference )
    #       raise "unimplemented case"
    #     else
    #       method = @receiver.get_singeton_method @method_name
    #       # Find the method for the given object (receiver) according to ruby dispatch rules:
    #         # - see if the receiver object has a (singleton) method by the name
    #         # - get receivers class and look for instance methods of the name
    #         # - go up inheritance tree
    #         # - start over with method_missing instead
    #         #    -> guaranteed to end at object.method_missing
    #       unless method
    #         cl = @receiver.layout.object_class
    #         method = cl.get_instance_or_super_method @method_name
    #       end
    #     end
    #   end
    #   unless method
    #     message = Message.new( @receiver , :method_missing , [@method_name] + @args)
    #     message.send
    #   else
    #     method.call
    #   end
    # end
  end
end