package se.six.cs.comm.cub;



import com.sun.grizzly.ProtocolParser;

import java.nio.ByteBuffer;

import se.six.cs.xflow.message.XFlowMessage;

public class XFlowProtocolParser implements ProtocolParser<XFlowMessage> {

  private ByteBuffer saved;

  /*
  To fullfill the interface contract with we need to have a hasNextMessage() method.
  Since finding out if we have a message could be said to be the same thing as
  finding out by parsing, we have current_message that we store the message we have
  parsed but not yet delivered.
   */
  private XFlowMessage current_message;
  private boolean wants_more_data = false;
  private boolean has_more_data = false;
  private int pos = 0;

  public XFlowProtocolParser() {
    System.out.println("XFlowProtocolParser created...");

  }

  public boolean isExpectingMoreData() {
    return wants_more_data;  
  }

  public boolean hasMoreBytesToParse() {
    return has_more_data;
  }

  public XFlowMessage getNextMessage() {
    if (current_message == null) {
      current_message = xGetXFlowMessage();
    }
    XFlowMessage tmp_msg = null;
    if (current_message != null) {
      tmp_msg = current_message;
      current_message = null;
    }
    return tmp_msg;
  }

  public boolean hasNextMessage() {
    if (current_message == null) {
      current_message = xGetXFlowMessage();
    }
    return (current_message != null);
  }

  public void startBuffer(ByteBuffer byteBuffer) {
    saved = byteBuffer;
    saved.flip();
    System.out.println("\n********\nstartBuffer: Message buffer size : "+saved.limit()+"\n***********\n");
    has_more_data = true;
    current_message = null;
  }

  private void xPrintBufferStats(ByteBuffer bb) {
    System.out.println(" Position : "+bb.position()+" Limit: "+bb.limit());
  }

  public boolean releaseBuffer() {
    if (wants_more_data) {

      saved.compact();
    } else {
      saved.clear();
    }
    return wants_more_data;  //To change body of implemented methods use File | Settings | File Templates.
  }

  /*
  The most common case:
   */

  private XFlowMessage xGetXFlowMessage() {
    XFlowMessage msg = null;
    if (!saved.hasRemaining()) {
      wants_more_data = false;
      has_more_data = false;
      saved.clear();
      return null;

    }
    // we need to save the position if there isn't a complete message in the buffer.
    pos = saved.position();
    
    // the XFlowMessage contains its own parser.
    msg = XFlowMessage.parse(saved);
    if (msg == null) { // not enough bytes in the buffer
      wants_more_data = true;
      has_more_data = false;
        saved.position(pos);
    } else {
      if (saved.position() == saved.limit()) {
        has_more_data = false;
      } else {
        has_more_data = true;
      }
    }
    return msg;
  }
}