class Network

  def initialize
    @message = nil
    @m_size = 0
  end

  def update
    until @socket.eof?
      if @message
        receive_message_gradually
      else
        receive_full_message
      end
    end
  end

  def receive_message_gradually
    message = @socket.recv_non_block(@m_size - @message.size)
    if connection_lost?(message)
      $alert_msg ||= Vocab::ConnectionFailed
      DataManager.back_login
      return
    end
    @message << message
    if @message.size - 4 == @m_size
      buffer = Buffer_Reader.new(@message)
      handle_messages(buffer)
      @message = nil
    end
  end

  def receive_full_message
    bytes = @socket.recv_non_block(2)
    if connection_lost?(bytes)
      $alert_msg ||= Vocab::ConnectionFailed
      DataManager.back_login
      return
    end
    size = bytes.unpack('s')[0]
    message = @socket.recv_non_block(size)
    if message.size - 4 == size
      buffer = Buffer_Reader.new(message)
      handle_messages(buffer)
    else
      @message = message
      @m_size = size
    end
  end

end