import org.hipparchus.ode.events.Action;
import org.orekit.orbits.KeplerianOrbit;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.events.ApsideDetector;
import org.orekit.propagation.events.handlers.EventHandler;
import org.orekit.time.AbsoluteDate;

public class ApsideCounterOrekit implements EventHandler<ApsideDetector> {

    private int apogeeCount;
    private int perigeeCount;

    public ApsideCounterOrekit() {
        super();
    }

    @Override
    public void init(SpacecraftState initialState, AbsoluteDate target) {
        apogeeCount = (int) initialState.getAdditionalState("ApsideNumber")[0];
        perigeeCount = (int) initialState.getAdditionalState("ApsideNumber")[1];
    }

    @Override
    public Action eventOccurred(SpacecraftState s, ApsideDetector detector, boolean increasing) {
        if (increasing) {
            if (detector.isForward()) {
                perigeeCount = perigeeCount + 1;
            }
            else {
                perigeeCount = perigeeCount - 1;
            }
        }
        else {
            if (detector.isForward()) {
                apogeeCount = apogeeCount + 1;
            }
            else {
                apogeeCount = apogeeCount - 1;
            }
            System.out.println("Apogee detected, mean ano is" + new KeplerianOrbit(s.getOrbit()).getMeanAnomaly() + " rad at orbit #" + apogeeCount);
        }
        return Action.RESET_STATE;
    }

    @Override
    public SpacecraftState resetState(ApsideDetector detector, SpacecraftState oldState) {
        double[] apsideCounters = new double[2];
        apsideCounters[0] = apogeeCount;
        apsideCounters[1] = perigeeCount;
        return oldState.addAdditionalState("ApsideNumber", apsideCounters);
    }
}