/* Copyright 2002-2022 CS GROUP
    * 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.estimation;
  
  import java.util.List;
  import java.util.Map;
  
  import org.hipparchus.geometry.euclidean.threed.Vector3D;
  import org.hipparchus.util.FastMath;
  import org.hipparchus.util.Pair;
  import org.orekit.bodies.CelestialBody;
  import org.orekit.bodies.GeodeticPoint;
  import org.orekit.bodies.OneAxisEllipsoid;
  import org.orekit.estimation.measurements.GroundStation;
  import org.orekit.forces.drag.DragSensitive;
  import org.orekit.forces.gravity.potential.NormalizedSphericalHarmonicsProvider;
  import org.orekit.forces.radiation.RadiationSensitive;
  import org.orekit.frames.TopocentricFrame;
  import org.orekit.models.earth.displacement.StationDisplacement;
  import org.orekit.orbits.CartesianOrbit;
  import org.orekit.orbits.Orbit;
  import org.orekit.orbits.OrbitType;
  import org.orekit.orbits.PositionAngle;
  import org.orekit.propagation.conversion.DormandPrince853IntegratorBuilder;
  import org.orekit.propagation.conversion.NumericalPropagatorBuilder;
  import org.orekit.time.TimeScale;
  import org.orekit.time.UT1Scale;
  import org.orekit.utils.IERSConventions;
  import org.orekit.utils.PVCoordinates;
  
  public class Context implements StationDataProvider {
      public IERSConventions                      conventions;
      public OneAxisEllipsoid                     earth;
      public CelestialBody                        sun;
      public CelestialBody                        moon;
      public RadiationSensitive                   radiationSensitive;
      public DragSensitive                        dragSensitive;
      public NormalizedSphericalHarmonicsProvider gravity;
      public TimeScale                            utc;
      public UT1Scale                             ut1;
      public Orbit                                initialOrbit;
      public StationDisplacement[]                displacements;
      public List<GroundStation>                  stations;
      // Stations for turn-around range
      // Map entry = primary station
      // Map value = secondary station associated
      public Map<GroundStation, GroundStation>     TARstations;
      // Stations for bistatic range rate
      // key/first    = emitter station
      // value/second = receiver station
      public Pair<GroundStation, GroundStation>    BRRstations;
      // Stations for TDOA
      // key/first    = primary station that dates the measurement
      // value/second = secondary station associated
      public Pair<GroundStation, GroundStation>    TDOAstations;
  
      public NumericalPropagatorBuilder createBuilder(final OrbitType orbitType, final PositionAngle positionAngle,
                                                      final boolean perfectStart,
                                                      final double minStep, final double maxStep, final double dP,
                                                      final Force... forces) {
  
          final Orbit startOrbit;
          if (perfectStart) {
              // orbit estimation will start from a perfect orbit
              startOrbit = initialOrbit;
          } else {
              // orbit estimation will start from a wrong point
              final Vector3D initialPosition = initialOrbit.getPVCoordinates().getPosition();
              final Vector3D initialVelocity = initialOrbit.getPVCoordinates().getVelocity();
              final Vector3D wrongPosition   = initialPosition.add(new Vector3D(1000.0, 0, 0));
              final Vector3D wrongVelocity   = initialVelocity.add(new Vector3D(0, 0, 0.01));
              startOrbit                     = new CartesianOrbit(new PVCoordinates(wrongPosition, wrongVelocity),
                                                                  initialOrbit.getFrame(),
                                                                  initialOrbit.getDate(),
                                                                  initialOrbit.getMu());
          }
          final NumericalPropagatorBuilder propagatorBuilder =
                          new NumericalPropagatorBuilder(orbitType.convertType(startOrbit),
                                                         new DormandPrince853IntegratorBuilder(minStep, maxStep, dP),
                                                         positionAngle, dP);
          for (Force force : forces) {
              propagatorBuilder.addForceModel(force.getForceModel(this));
          }
  
          return propagatorBuilder;
 
     }
 
     GroundStation createStation(double latitudeInDegrees, double longitudeInDegrees,
                                 double altitude, String name) {
         final GeodeticPoint gp = new GeodeticPoint(FastMath.toRadians(latitudeInDegrees),
                                                    FastMath.toRadians(longitudeInDegrees),
                                                    altitude);
         return new GroundStation(new TopocentricFrame(earth, gp, name),
                                  ut1.getEOPHistory(), displacements);
     }
 
     @Override
     public List<GroundStation> getStations() {
         return stations;
     }
 
 }