/* 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.propagation.numerical;
  
  import org.hipparchus.geometry.euclidean.threed.Vector3D;
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.params.ParameterizedTest;
  import org.junit.jupiter.params.provider.EnumSource;
  import org.orekit.TestUtils;
  import org.orekit.forces.ForceModel;
  import org.orekit.forces.gravity.NewtonianAttraction;
  import org.orekit.orbits.Orbit;
  import org.orekit.orbits.OrbitType;
  import org.orekit.orbits.PositionAngleType;
  import org.orekit.propagation.SpacecraftState;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.utils.Constants;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import static org.junit.jupiter.api.Assertions.*;
  
  class NumericalTimeDerivativesEquationsTest {
  
      @ParameterizedTest
      @EnumSource(value = OrbitType.class, names = {"EQUINOCTIAL", "KEPLERIAN", "CIRCULAR"})
      void testComputeTimeDerivatives(final OrbitType orbitType) {
          // GIVEN
          final Orbit orbit = TestUtils.getDefaultOrbit(AbsoluteDate.ARBITRARY_EPOCH);
          final SpacecraftState state = new SpacecraftState(orbit);
          final List<ForceModel> forceModelList = new ArrayList<>();
          final ForceModel forceModel = new NewtonianAttraction(Constants.EGM96_EARTH_MU);
          forceModelList.add(forceModel);
          final NumericalTimeDerivativesEquations equations = new NumericalTimeDerivativesEquations(orbitType,
                  PositionAngleType.MEAN, forceModelList);
          // WHEN
          final double[] derivatives = equations.computeTimeDerivatives(state);
          // THEN
          assertEquals(7, derivatives.length);
          for (int i = 0; i < 7; i++) {
              if (i == 5) {
                  assertNotEquals(0., derivatives[i]);
              } else {
                  assertEquals(0., derivatives[i]);
              }
          }
      }
  
      @Test
      void testComputeTimeDerivativesCartesian() {
          // GIVEN
          final Orbit orbit = TestUtils.getDefaultOrbit(AbsoluteDate.ARBITRARY_EPOCH);
          final SpacecraftState state = new SpacecraftState(orbit);
          final List<ForceModel> forceModelList = new ArrayList<>();
          final NewtonianAttraction forceModel = new NewtonianAttraction(Constants.EGM96_EARTH_MU);
          forceModelList.add(forceModel);
          final NumericalTimeDerivativesEquations equations = new NumericalTimeDerivativesEquations(OrbitType.CARTESIAN,
                  PositionAngleType.MEAN, forceModelList);
          // WHEN
          final double[] derivatives = equations.computeTimeDerivatives(state);
          // THEN
          assertEquals(state.getVelocity().getX(), derivatives[0]);
          assertEquals(state.getVelocity().getY(), derivatives[1]);
          assertEquals(state.getVelocity().getZ(), derivatives[2]);
          final Vector3D acceleration = forceModel.acceleration(state, new double[] {forceModel.getMu(orbit.getDate())});
          final double tolerance = 1e-10;
          assertEquals(acceleration.getX(), derivatives[3], tolerance);
          assertEquals(acceleration.getY(), derivatives[4], tolerance);
          assertEquals(acceleration.getZ(), derivatives[5], tolerance);
          assertEquals(0, derivatives[6]);
      }
  }