module EventMachine
  module WebSocket
    module MessageProcessor06
      def message(message_type, extension_data, application_data)
        debug [:message_received, message_type, application_data]
        
        case message_type
        when :close
          status_code = case application_data.length
          when 0
            # close messages MAY contain a body
            nil
          when 1
            # Illegal close frame
            raise WSProtocolError, "Close frames with a body must contain a 2 byte status code"
          else
            application_data.slice!(0, 2).unpack('n').first
          end
          
          debug [:close_frame_received, status_code, application_data]
          
          @close_info = {
            :code => status_code || 1005,
            :reason => application_data,
            :was_clean => true,
          }

          if @state == :closing
            # We can close connection immediately since no more data may be
            # sent or received on this connection
            @connection.close_connection
          elsif @state == :connected
            # Acknowlege close & echo status back to client
            # The connection is considered closed
            close_data = [status_code || 1000].pack('n')
            send_frame(:close, close_data)
            @connection.close_connection_after_writing
          end
        when :ping
          # There are a couple of protections here against malicious/broken WebSocket abusing ping frames.
          #
          # 1. Delay 200ms before replying. This reduces the number of pings from WebSocket clients behaving as
          #    `for (;;) { send_ping(conn); rcv_pong(conn); }`. The spec says we "SHOULD respond with Pong frame as soon
          #    as is practical".
          # 2. Reply at most every 200ms. This reduces the number of pong frames sent to WebSocket clients behaving as
          #    `for (;;) { send_ping(conn); }`. The spec says "If an endpoint receives a Ping frame and has not yet sent
          #    Pong frame(s) in response to previous Ping frame(s), the endpoint MAY elect to send a Pong frame for only
          #    the most recently processed Ping frame."
          @most_recent_pong_application_data = application_data
          if @pong_timer == nil then
            @pong_timer = EventMachine.add_timer(0.2) do
              @pong_timer = nil
              send_frame(:pong, @most_recent_pong_application_data)
            end
          end
          @connection.trigger_on_ping(application_data)
        when :pong
          @connection.trigger_on_pong(application_data)
        when :text
          if application_data.respond_to?(:force_encoding)
            application_data.force_encoding("UTF-8")
            unless application_data.valid_encoding?
              raise InvalidDataError, "Invalid UTF8 data"
            end
          end
          @connection.trigger_on_message(application_data)
        when :binary
          @connection.trigger_on_binary(application_data)
        end
      end

      # Ping & Pong supported
      def pingable?
        true
      end
    end
  end
end