/* Copyright 2020 Airbus Defence and Space
    * Licensed to CS GROUP (CS) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * CS licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.orekit.propagation.events.handlers;
  
  import org.hipparchus.ode.events.Action;
  import org.junit.Assert;
  import org.junit.Before;
  import org.junit.Test;
  import org.orekit.Utils;
  import org.orekit.frames.Frame;
  import org.orekit.frames.FramesFactory;
  import org.orekit.orbits.KeplerianOrbit;
  import org.orekit.orbits.Orbit;
  import org.orekit.orbits.PositionAngle;
  import org.orekit.propagation.SpacecraftState;
  import org.orekit.propagation.events.DateDetector;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.utils.Constants;
  
  /**
   * Unit tests for {@link EventMultipleHandler}.
   *
   * @author Lara Hué
   */
  public class EventMultipleHandlerTest {
  
      @Before
      public void setUp() {
          Utils.setDataRoot("regular-data");
      }
      
       /**
       * check eventOccurred method.
       */
      @Test
      public void testEventOccurred() {
          // setup
          ContinueOnEvent<DateDetector> handler1 = new ContinueOnEvent<>();
          StopOnEvent<DateDetector> handler2 = new StopOnEvent<>();
          StopOnDecreasing<DateDetector> handler3 = new StopOnDecreasing<>();
          AbsoluteDate date = AbsoluteDate.J2000_EPOCH;
          DateDetector detector = new DateDetector(date);
          Frame eci = FramesFactory.getGCRF();
          Orbit orbit = new KeplerianOrbit(6378137 + 500e3, 0, 0, 0, 0, 0,
                  PositionAngle.TRUE, eci, date, Constants.EIGEN5C_EARTH_MU);
          SpacecraftState s = new SpacecraftState(orbit);
  
          // actions
          EventMultipleHandler<DateDetector> facade1 = new EventMultipleHandler<DateDetector>().addHandler(handler1).addHandler(handler2);
          Assert.assertEquals(Action.STOP, facade1.eventOccurred(s, detector, true));
  
          EventMultipleHandler<DateDetector> facade2 = new EventMultipleHandler<DateDetector>().addHandler(handler1).addHandler(handler3);
          Assert.assertEquals(Action.CONTINUE, facade2.eventOccurred(s, detector, true));
      }
      
      /**
       * check resetState method.
       */
      @Test
      public void testResetState() {
          // setup
          ContinueOnEvent<DateDetector> handler1 = new ContinueOnEvent<>();
          AbsoluteDate date = AbsoluteDate.J2000_EPOCH;
          DateDetector detector = new DateDetector(date);
          Frame eci = FramesFactory.getGCRF();
          Orbit orbit = new KeplerianOrbit(6378137 + 500e3, 0, 0, 0, 0, 0,
                                           PositionAngle.TRUE, eci, date, Constants.EIGEN5C_EARTH_MU);
          SpacecraftState s = new SpacecraftState(orbit);
          
          // actions
          EventHandler<DateDetector> handler2 = getHandler(10);
          EventHandler<DateDetector> handler3 = getHandler(20);
          EventMultipleHandler<DateDetector> facade = new EventMultipleHandler<DateDetector>().addHandlers(handler1, handler2, handler3);
  
          // verify
          Assert.assertEquals(Action.RESET_STATE, facade.eventOccurred(s, detector, true));
          Assert.assertEquals(s.shiftedBy(30).getOrbit().getDate(), facade.resetState(detector, s).getOrbit().getDate());
      }
  
      /**
       * get a handler that returns action RESET_STATE and shifts orbit
       */
      private EventHandler<DateDetector> getHandler(double timeShift) {
  
          return new EventHandler<DateDetector>() {
 
             @Override
             public Action eventOccurred(SpacecraftState s, DateDetector detector, boolean increasing) {
                 return Action.RESET_STATE;
             }
 
             @Override
             public SpacecraftState resetState(DateDetector detector, SpacecraftState oldState) {
                 return oldState.shiftedBy(timeShift);
             }
         };
     }
 }