/**
 * A basic implementation for the EchoTestAnalyzer.
 */
public class BasicEchoTestAnalyzer implements EchoTestAnalyzer {

    /**
     * How many events must appear until a detailed report is
     * printed. Default is every 20 events.
     */
    private static int REPORT_DELAY = 20;
    
    private static int SUMMARY_SIZE = 100;

    public BasicEchoTestAnalyzer() {
	this(20, 100);
    }
    
    public BasicEchoTestAnalyzer(int reportDelay, int summarySize) {
	REPORT_DELAY = reportDelay;
	SUMMARY_SIZE = summarySize;
    }
    
    private int events = 0,
	packetLosses = 0,
	packetLossesDisconnect=0,
	disconnects = 0,
	disconnectsRefused = 0,
	delayCount=0,
	lastDelayPtr = 0;
    private long minDelay=Long.MAX_VALUE, maxDelay = 0, delaySum=0;
    private long[] lastDelays = new long[SUMMARY_SIZE];
    
    
    public synchronized void packetLossOccurred(boolean beforeDisconnect) {
	System.out.println("1: Packet lost"+
			   (beforeDisconnect?" before disconnect":"")+
			   ".");
	packetLosses++;
	if (beforeDisconnect) packetLossesDisconnect++;
	countEvent();
    }

    public synchronized void successOccurred(long delay) {
	System.out.println("0: Delay = "+delay);
	if (delay > maxDelay) maxDelay=delay;
	if (delay < minDelay) minDelay=delay;
	delaySum+=delay;
	delayCount++;
	lastDelays[lastDelayPtr++]=delay;
	lastDelayPtr%=SUMMARY_SIZE;
	countEvent();
    }

    public synchronized void disconnected(boolean refused) {
	System.out.println("2: Disconnected"+
			   (refused?" (connection refused)":"")+
			   ".");
	disconnects++;
	if (refused) disconnectsRefused++;
	countEvent();
    }

    private void countEvent() {
	events++;
	if (events % REPORT_DELAY == 0) {
	    int packets = packetLosses+delayCount;
	    long delaySummary=0;
	    for (int i=0;i<SUMMARY_SIZE;i++) {
		delaySummary+=lastDelays[i];
	    }
	    System.out.println
		("++++++++++++++++ ECHO STATISTICS +++++++++++++++++++++++++"+
		 "\n++ Number of total echo messages: "+packets+
		 "\n++ No response for "+packetLosses+
		 "\n++    (of which "+ packetLossesDisconnect+
		 " due to a disconnect)"+
		 "\n++ Disconnects: "+disconnects+
		 "\n++    (of which "+disconnectsRefused+
		 " due to 'connection refused')"+
		 (disconnects>0 || true
		  ?"\n++ Average lost packets per disconnect: "+
		  (packetLossesDisconnect/(float)disconnects)
		  :"")+
		 "\n++++++++++++++++++++++++++++++++++++++++++++++++++++++++"+
		 "\n++ Minimal delay: "+minDelay+
		 "\n++ Average delay: "+(delaySum/(float)delayCount)+
		 "\n++ Maximal delay: "+maxDelay+
		 (delayCount >=SUMMARY_SIZE
		  ?"\n++ Average delay over last " + SUMMARY_SIZE + ": "+(delaySummary/(float)SUMMARY_SIZE)
		  :"")+
		 "\n++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
	}
    }
}