/* Copyright 2022-2025 Romain Serra
    * 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.orbits;
  
  import org.hipparchus.complex.Complex;
  import org.hipparchus.complex.ComplexField;
  import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
  import org.hipparchus.geometry.euclidean.threed.Vector3D;
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.Test;
  import org.orekit.frames.FramesFactory;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.utils.FieldPVCoordinates;
  import org.orekit.utils.PVCoordinates;
  
  class KeplerianMotionCartesianUtilityTest {
  
      private static final double TOLERANCE_DISTANCE = 1e-14;
      private static final double TOLERANCE_SPEED = 1e-15;
  
      @Test
      void testPredictPositionVelocityElliptic() {
          // GIVEN
          final double mu = 1.;
          final Vector3D position = new Vector3D(10., 1., 0.);
          final Vector3D velocity = new Vector3D(0., 0.1, 0.2);
          // WHEN & THEN
          for (double dt = -10.; dt <= 10.; dt += 0.1) {
              final PVCoordinates actualPV = KeplerianMotionCartesianUtility.predictPositionVelocity(dt, position,
                      velocity, mu);
              final CartesianOrbit orbit = new CartesianOrbit(new PVCoordinates(position, velocity), FramesFactory.getGCRF(),
                      AbsoluteDate.ARBITRARY_EPOCH, mu);
              final EquinoctialOrbit equinoctialOrbit = new EquinoctialOrbit(orbit);
              final PVCoordinates expectedPV = equinoctialOrbit.shiftedBy(dt).getPVCoordinates();
              comparePV(expectedPV, actualPV);
          }
      }
  
      @Test
      void testPredictPositionVelocityHyperbolic() {
          // GIVEN
          final double mu = 1.;
          final Vector3D position = new Vector3D(10., 1., 0.);
          final Vector3D velocity = new Vector3D(0., 0.1, 1.);
          // WHEN & THEN
          for (double dt = -10.; dt <= 10.; dt += 0.1) {
              final PVCoordinates actualPV = KeplerianMotionCartesianUtility.predictPositionVelocity(dt, position,
                      velocity, mu);
              final CartesianOrbit orbit = new CartesianOrbit(new PVCoordinates(position, velocity), FramesFactory.getGCRF(),
                      AbsoluteDate.ARBITRARY_EPOCH, mu);
              final KeplerianOrbit keplerianOrbit = new KeplerianOrbit(orbit);
              final PVCoordinates expectedPV = keplerianOrbit.shiftedBy(dt).getPVCoordinates();
              comparePV(expectedPV, actualPV);
          }
      }
  
      private void comparePV(final PVCoordinates pvCoordinates, final PVCoordinates otherPVCoordinates) {
          final double expectedValue = 0.;
          final PVCoordinates relativePV = new PVCoordinates(pvCoordinates, otherPVCoordinates);
          Assertions.assertEquals(expectedValue, relativePV.getPosition().getNorm(), TOLERANCE_DISTANCE);
          Assertions.assertEquals(expectedValue, relativePV.getVelocity().getNorm(), TOLERANCE_SPEED);
      }
  
      @Test
      void testPredictPositionVelocityEllipticField() {
          // GIVEN
          final ComplexField field = ComplexField.getInstance();
          final double mu = 1.;
          final Vector3D position = new Vector3D(6., 0., 1.);
          final Vector3D velocity = new Vector3D(0.01, 0.1, 0.);
          final Complex fieldMu = new Complex(mu);
          final FieldVector3D<Complex> fieldPosition = new FieldVector3D<>(field, position);
          final FieldVector3D<Complex> fieldVelocity = new FieldVector3D<>(field, velocity);
          // WHEN & THEN
          for (double dt = -10.; dt <= 10.; dt += 0.1) {
              final FieldPVCoordinates<Complex> actualPV = KeplerianMotionCartesianUtility.predictPositionVelocity(new Complex(dt),
                      fieldPosition, fieldVelocity, fieldMu);
              final PVCoordinates expectedPV = KeplerianMotionCartesianUtility.predictPositionVelocity(dt, position,
                      velocity, mu);
              comparePV(expectedPV, actualPV.toPVCoordinates());
          }
      }
  
      @Test
      void testPredictPositionVelocityHyperbolicField() {
         // GIVEN
         final ComplexField field = ComplexField.getInstance();
         final double mu = 1.;
         final Vector3D position = new Vector3D(6., 0., 2.);
         final Vector3D velocity = new Vector3D(0.01, 1, 0.);
         final Complex fieldMu = new Complex(mu);
         final FieldVector3D<Complex> fieldPosition = new FieldVector3D<>(field, position);
         final FieldVector3D<Complex> fieldVelocity = new FieldVector3D<>(field, velocity);
         // WHEN & THEN
         for (double dt = -10.; dt <= 10.; dt += 0.1) {
             final FieldPVCoordinates<Complex> actualPV = KeplerianMotionCartesianUtility.predictPositionVelocity(new Complex(dt),
                     fieldPosition, fieldVelocity, fieldMu);
             final PVCoordinates expectedPV = KeplerianMotionCartesianUtility.predictPositionVelocity(dt, position,
                     velocity, mu);
             comparePV(expectedPV, actualPV.toPVCoordinates());
         }
     }
 
 }