/* 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.control.indirect.adjoint;
  
  import org.hipparchus.analysis.differentiation.Gradient;
  import org.hipparchus.analysis.differentiation.GradientField;
  import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
  import org.hipparchus.util.Binary64;
  import org.hipparchus.util.Binary64Field;
  import org.hipparchus.util.MathArrays;
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.Test;
  import org.mockito.Mockito;
  import org.orekit.forces.gravity.NewtonianAttraction;
  import org.orekit.frames.Frame;
  import org.orekit.frames.FramesFactory;
  import org.orekit.propagation.FieldSpacecraftState;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.time.FieldAbsoluteDate;
  import org.orekit.utils.Constants;
  
  class CartesianAdjointKeplerianTermTest {
  
      @Test
      @SuppressWarnings("unchecked")
      void testGetPositionAdjointContribution() {
          // GIVEN
          final CartesianAdjointKeplerianTerm keplerianTerm = new CartesianAdjointKeplerianTerm(Constants.EGM96_EARTH_MU);
          final double[] adjoint = new double[6];
          final double[] state = new double[6];
          for (int i = 0; i < adjoint.length; i++) {
              state[i] = -i+1;
              adjoint[i] = i;
          }
          // WHEN
          final double[] contribution = keplerianTerm.getPositionAdjointContribution(Mockito.mock(AbsoluteDate.class),
                  state, adjoint, FramesFactory.getGCRF());
          // THEN
          final NewtonianAttraction newtonianAttraction = new NewtonianAttraction(keplerianTerm.getMu());
          final int dimension = 3;
          final GradientField field = GradientField.getField(dimension);
          final FieldSpacecraftState<Gradient> mockedState = Mockito.mock(FieldSpacecraftState.class);
          final FieldVector3D<Gradient> fieldPosition = new FieldVector3D<>(
                  Gradient.variable(dimension, 0, state[0]),
                  Gradient.variable(dimension, 1, state[1]),
                  Gradient.variable(dimension, 2, state[2]));
          Mockito.when(mockedState.getPosition()).thenReturn(fieldPosition);
          final Gradient[] fieldMu = MathArrays.buildArray(field, 1);
          fieldMu[0] = Gradient.constant(dimension, keplerianTerm.getMu());
          final FieldVector3D<Gradient> acceleration = newtonianAttraction.acceleration(mockedState, fieldMu);
          Assertions.assertEquals(-contribution[0], acceleration.getX().getGradient()[0] * adjoint[3]
                  + acceleration.getY().getGradient()[0] * adjoint[4] + acceleration.getZ().getGradient()[0] * adjoint[5]);
          Assertions.assertEquals(-contribution[1], acceleration.getX().getGradient()[1] * adjoint[3]
                  + acceleration.getY().getGradient()[1] * adjoint[4] + acceleration.getZ().getGradient()[1] * adjoint[5]);
          Assertions.assertEquals(-contribution[2], acceleration.getX().getGradient()[2] * adjoint[3]
                  + acceleration.getY().getGradient()[2] * adjoint[4] + acceleration.getZ().getGradient()[2] * adjoint[5]);
      }
  
      @Test
      void testGetPositionAdjointFieldContribution() {
          // GIVEN
          final CartesianAdjointKeplerianTerm keplerianTerm = new CartesianAdjointKeplerianTerm(Constants.EGM96_EARTH_MU);
          final Binary64Field field = Binary64Field.getInstance();
          final Binary64[] fieldAdjoint = MathArrays.buildArray(field, 6);
          final Binary64[] fieldState = MathArrays.buildArray(field, 6);
          for (int i = 0; i < fieldAdjoint.length; i++) {
              fieldState[i] = field.getZero().newInstance(-i+1);
              fieldAdjoint[i] = field.getZero().newInstance(i);
          }
          final Frame frame = FramesFactory.getGCRF();
          final FieldAbsoluteDate<Binary64> fieldDate = FieldAbsoluteDate.getArbitraryEpoch(field);
          // WHEN
          final Binary64[] fieldContribution = keplerianTerm.getPositionAdjointFieldContribution(fieldDate, fieldState,
                  fieldAdjoint, frame);
          // THEN
          final double[] state = new double[fieldState.length];
          for (int i = 0; i < fieldState.length; i++) {
              state[i] = fieldState[i].getReal();
          }
          final double[] adjoint = new double[fieldAdjoint.length];
          for (int i = 0; i < fieldAdjoint.length; i++) {
              adjoint[i] = fieldAdjoint[i].getReal();
          }
          final double[] contribution = keplerianTerm.getPositionAdjointContribution(fieldDate.toAbsoluteDate(), state,
                  adjoint, frame);
         for (int i = 0; i < contribution.length; i++) {
             Assertions.assertEquals(fieldContribution[i].getReal(), contribution[i]);
         }
     }
 }