package rep;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;

public class REPPacketReceive {
	
	SocketChannel socketchannel;
	private int HEADER_SIZE = 24;
	
	public REPPacketReceive(SocketChannel sc){
		socketchannel = sc;
	}

	
	public REPCommand unpack() {

		ByteBuffer header = ByteBuffer.allocateDirect(HEADER_SIZE);
		long len = 0;
		header.clear();
		try {
			len = socketchannel.read(header);
			if(len == -1){
				socketchannel.close();
				return null;
			}else if(len == 0){
				return null;
			}
		} catch (IOException e1) {
			e1.printStackTrace();
		}  // limit = read length
		if (len !=HEADER_SIZE) {
			System.out.println("‚Ä‚·");
			// this can't happen
		}
		header.rewind();  // position = 0

		String text = "";
		int cmd = header.getInt();
		int sid = header.getInt();
		int eid = header.getInt();
		int seqid = header.getInt();
		int lineno = header.getInt();
		int textsiz = header.getInt()/2;
		
		ByteBuffer textBuffer = ByteBuffer.allocateDirect(textsiz*2);

		try {
			len = socketchannel.read(textBuffer);
		} catch (IOException e1) {
			e1.printStackTrace();
		}  // limit = read length
		if (len != textsiz * 2) {
			// this can't happen
			System.out.println("‚ ‚Æ");
		}
		textBuffer.rewind();
		for(int i=0;i<textsiz;i++) {
			text +=textBuffer.getChar();
		}
		String string = text;
		//System.out.println(string);
		REPCommand repcommand = new REPCommand(cmd, sid, eid, seqid, lineno, textsiz, string);
		System.out.println("received command: " + repcommand.toString());
		return repcommand;
	}
}