/* Copyright 2022-2026 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.estimation.measurements;
  
  import org.hipparchus.CalculusFieldElement;
  import org.hipparchus.Field;
  import org.hipparchus.geometry.euclidean.threed.FieldRotation;
  import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
  import org.hipparchus.geometry.euclidean.threed.Rotation;
  import org.hipparchus.geometry.euclidean.threed.Vector3D;
  import org.orekit.bodies.BodyShape;
  import org.orekit.bodies.FieldGeodeticPoint;
  import org.orekit.bodies.GeodeticPoint;
  import org.orekit.data.BodiesElements;
  import org.orekit.data.FundamentalNutationArguments;
  import org.orekit.frames.FieldStaticTransform;
  import org.orekit.frames.FieldTransform;
  import org.orekit.frames.Frame;
  import org.orekit.frames.StaticTransform;
  import org.orekit.frames.TopocentricFrame;
  import org.orekit.frames.Transform;
  import org.orekit.frames.TransformProvider;
  import org.orekit.models.earth.displacement.StationDisplacement;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.time.FieldAbsoluteDate;
  import org.orekit.utils.ParameterDriver;
  
  /** Class modeling a ground station frame transform.
   * <p>
   * This class considers a position offset parameter w.r.t. a base {@link TopocentricFrame
   * topocentric frame}.
   * </p>
   * <p>
   * This class also adds parameters for an additional polar motion
   * and an additional prime meridian orientation. Since these parameters will
   * have the same name for all ground stations, they will be managed consistently
   * and allow to estimate Earth orientation precisely (this is needed for precise
   * orbit determination). The polar motion and prime meridian orientation will
   * be applied <em>after</em> regular Earth orientation parameters, so the value
   * of the estimated parameters will be correction to EOP, they will not be the
   * complete EOP values by themselves. Basically, this means that for Earth, the
   * following transforms are applied in order, between inertial frame and ground
   * station frame (for non-Earth based ground stations, different precession nutation
   * models and associated planet orientation parameters would be applied, if available):
   * </p>
   * @author Romain Serra
   * @since 14.0
   */
  class GroundStationTransformProvider implements TransformProvider {
  
      /**
       * Target frame.
       */
      private final Frame frame;
  
      /** Provider for Earth frame whose EOP parameters can be estimated. */
      private final EstimatedEarthFrameProvider estimatedEarthFrameProvider;
  
      /** Earth frame whose EOP parameters can be estimated. */
      private final Frame estimatedEarthFrame;
  
      /** Base frame associated with the station. */
      private final TopocentricFrame baseFrame;
  
      /** Fundamental nutation arguments. */
      private final FundamentalNutationArguments arguments;
  
      /** Displacement models. */
      private final StationDisplacement[] displacements;
  
      /** Driver for position offset along the East axis. */
      private final ParameterDriver eastOffsetDriver;
  
      /** Driver for position offset along the North axis. */
      private final ParameterDriver northOffsetDriver;
  
      /** Driver for position offset along the zenith axis. */
      private final ParameterDriver zenithOffsetDriver;
  
       /**
       * Constructor.
       * @param frame target frame
       * @param baseFrame     base frame associated with the station, without *any* parametric model (no station offset,
       *                      no polar motion, no meridian shift)
       * @param eastOffsetDriver driver for position offset along the East axis
      * @param northOffsetDriver driver for position offset along the North axis
      * @param zenithOffsetDriver driver for position offset along the zenith axis
      * @param estimatedEarthFrameProvider provider for Earth frame whose EOP parameters can be estimated
      * @param fundamentalNutationArguments fundamental nutation arguments
      * @param displacements ground station displacement model (tides, ocean loading, atmospheric loading, thermal
      *                      effects...)
      */
     GroundStationTransformProvider(final Frame frame, final TopocentricFrame baseFrame,
                                    final ParameterDriver eastOffsetDriver,
                                    final ParameterDriver northOffsetDriver,
                                    final ParameterDriver zenithOffsetDriver,
                                    final EstimatedEarthFrameProvider estimatedEarthFrameProvider,
                                    final FundamentalNutationArguments fundamentalNutationArguments,
                                    final StationDisplacement... displacements) {
         this.frame = frame;
         this.baseFrame = baseFrame;
 
         this.estimatedEarthFrameProvider = estimatedEarthFrameProvider;
         this.estimatedEarthFrame = new Frame(baseFrame.getParent(), estimatedEarthFrameProvider,
                                              baseFrame.getParent() + "-estimated");
         this.arguments = fundamentalNutationArguments;
 
         this.displacements = displacements.clone();
         this.eastOffsetDriver   = eastOffsetDriver;
         this.northOffsetDriver  = northOffsetDriver;
         this.zenithOffsetDriver = zenithOffsetDriver;
     }
 
     /** {@inheritDoc} */
     @Override
     public Transform getTransform(final AbsoluteDate date) {
         // take Earth offsets into account
         final Transform intermediateToBody = estimatedEarthFrameProvider.getTransform(date).getInverse();
 
         // take station offsets into account
         final BodyShape baseShape = baseFrame.getParentShape();
         final Vector3D  origin    = getOrigin(date);
 
         final GeodeticPoint originGP = baseShape.transform(origin, baseShape.getBodyFrame(), date);
         final Transform offsetToIntermediate =
                         new Transform(date,
                                       new Transform(date,
                                                     new Rotation(Vector3D.PLUS_I, Vector3D.PLUS_K,
                                                                  originGP.getEast(), originGP.getZenith()),
                                                     Vector3D.ZERO),
                                       new Transform(date, origin));
         if (baseFrame.getParent() == frame) {
             return new Transform(date, offsetToIntermediate, intermediateToBody);
         }
 
         // combine all transforms together
         final Transform bodyToInert = baseFrame.getParent().getTransformTo(frame, date);
 
         return new Transform(date, offsetToIntermediate, new Transform(date, intermediateToBody, bodyToInert));
     }
 
     /** {@inheritDoc} */
     @Override
     public StaticTransform getStaticTransform(final AbsoluteDate date) {
         // take Earth offsets into account
         final StaticTransform intermediateToBody = estimatedEarthFrameProvider.getStaticTransform(date).getInverse();
 
         // take station offsets into account
         final BodyShape baseShape = baseFrame.getParentShape();
         final Vector3D  origin    = getOrigin(date);
 
         final GeodeticPoint originGP = baseShape.transform(origin, baseShape.getBodyFrame(), date);
         final StaticTransform offsetToIntermediate = StaticTransform.compose(date,
                         StaticTransform.of(date,
                                 new Rotation(Vector3D.PLUS_I, Vector3D.PLUS_K,
                                         originGP.getEast(), originGP.getZenith())),
                         StaticTransform.of(date, origin));
         if (baseFrame.getParent() == frame) {
             return StaticTransform.compose(date, offsetToIntermediate, intermediateToBody);
         }
 
         // combine all transforms together
         final StaticTransform bodyToInert = baseFrame.getParent().getStaticTransformTo(frame, date);
 
         return StaticTransform.compose(date, offsetToIntermediate, StaticTransform.compose(date, intermediateToBody, bodyToInert));
     }
 
     /**
      * Retrieve station's position in body shape frame.
      * @param date date
      * @return origin position
      */
     private Vector3D getOrigin(final AbsoluteDate date) {
         final double    x          = eastOffsetDriver.getValue(date);
         final double    y          = northOffsetDriver.getValue(date);
         final double    z          = zenithOffsetDriver.getValue(date);
         final Frame bodyFrame = baseFrame.getParentShape().getBodyFrame();
         final StaticTransform staticTopoToBody = baseFrame.getStaticTransformTo(bodyFrame, date);
         final Vector3D        originBeforeDisplacement     = staticTopoToBody.transformPosition(new Vector3D(x, y, z));
         return originBeforeDisplacement.add(computeDisplacement(date, originBeforeDisplacement));
     }
 
     /** Get the station displacement.
      * @param date current date
      * @param position raw position of the station in Earth frame
      * before displacement is applied
      * @return station displacement
      */
     private Vector3D computeDisplacement(final AbsoluteDate date, final Vector3D position) {
         Vector3D displacement = Vector3D.ZERO;
         if (arguments != null) {
             final BodiesElements elements = arguments.evaluateAll(date);
             for (final StationDisplacement sd : displacements) {
                 // we consider all displacements apply to the same initial position,
                 // i.e. they apply simultaneously, not according to some order
                 displacement = displacement.add(sd.displacement(elements, estimatedEarthFrame, position));
             }
         }
         return displacement;
     }
 
     /** {@inheritDoc} */
     @Override
     public <T extends CalculusFieldElement<T>> FieldTransform<T> getTransform(final FieldAbsoluteDate<T> date) {
 
         // take Earth offsets into account
         final FieldTransform<T> intermediateToBody = estimatedEarthFrameProvider.getTransform(date).getInverse();
 
         // take station offsets into account
         final FieldVector3D<T> origin = getOrigin(date);
         return getTransform(date, origin, intermediateToBody);
 
     }
 
     <T extends CalculusFieldElement<T>> FieldTransform<T> getTransform(final FieldAbsoluteDate<T> date,
                                                                        final FieldVector3D<T> origin,
                                                                        final FieldTransform<T> intermediateToBody) {
         final Field<T>         field = date.getField();
         final FieldVector3D<T> zero  = FieldVector3D.getZero(field);
         final FieldVector3D<T> plusI = FieldVector3D.getPlusI(field);
         final FieldVector3D<T> plusK = FieldVector3D.getPlusK(field);
         final FieldGeodeticPoint<T> originGP = baseFrame.getParentShape().transform(origin,
                 baseFrame.getParentShape().getBodyFrame(), date);
         final FieldTransform<T> offsetToIntermediate =
                 new FieldTransform<>(date,
                         new FieldTransform<>(date,
                                 new FieldRotation<>(plusI, plusK,
                                         originGP.getEast(), originGP.getZenith()),
                                 zero),
                         new FieldTransform<>(date, origin));
 
         // combine all transforms together
         if (baseFrame.getParent() == frame) {
             return new FieldTransform<>(date, offsetToIntermediate, intermediateToBody);
         }
         final FieldTransform<T> bodyToInert = baseFrame.getParent().getTransformTo(frame, date);
 
         return new FieldTransform<>(date, offsetToIntermediate,
                 new FieldTransform<>(date, intermediateToBody, bodyToInert));
 
     }
 
     /** {@inheritDoc} */
     @Override
     public <T extends CalculusFieldElement<T>> FieldStaticTransform<T> getStaticTransform(final FieldAbsoluteDate<T> date) {
 
         // take Earth offsets into account
         final FieldStaticTransform<T> intermediateToBody = estimatedEarthFrameProvider.getStaticTransform(date).getInverse();
 
         final FieldVector3D<T> origin = new FieldVector3D<>(date.getField(), getOrigin(date.toAbsoluteDate()));
         // take station offsets into account
         final Field<T>         field = date.getField();
         final FieldVector3D<T> plusI = FieldVector3D.getPlusI(field);
         final FieldVector3D<T> plusK = FieldVector3D.getPlusK(field);
         final FieldGeodeticPoint<T> originGP = baseFrame.getParentShape().transform(origin,
                 baseFrame.getParentShape().getBodyFrame(), date);
         final FieldStaticTransform<T> offsetToIntermediate = FieldStaticTransform.compose(date,
                 FieldStaticTransform.of(date,
                         new FieldRotation<>(plusI, plusK, originGP.getEast(), originGP.getZenith())),
                 FieldStaticTransform.of(date, origin));
 
         // combine all transforms together
         if (baseFrame.getParent() == frame) {
             return FieldStaticTransform.compose(date, offsetToIntermediate, intermediateToBody);
         }
         final FieldStaticTransform<T> bodyToInert = baseFrame.getParent().getStaticTransformTo(frame, date);
 
         return FieldStaticTransform.compose(date, offsetToIntermediate,
                 FieldStaticTransform.compose(date, intermediateToBody, bodyToInert));
     }
 
     /**
      * Retrieve station's position in body shape frame.
      * @param <T> field type
      * @param date date
      * @return origin position
      */
     private <T extends CalculusFieldElement<T>> FieldVector3D<T> getOrigin(final FieldAbsoluteDate<T> date) {
         final AbsoluteDate absoluteDate = date.toAbsoluteDate();
         final Field<T> field = date.getField();
         final T x          = field.getZero().newInstance(eastOffsetDriver.getValue(absoluteDate));
         final T                       y          = field.getZero().newInstance(northOffsetDriver.getValue(absoluteDate));
         final T                       z          = field.getZero().newInstance(zenithOffsetDriver.getValue(absoluteDate));
         final Frame bodyFrame = baseFrame.getParentShape().getBodyFrame();
         final FieldStaticTransform<T> staticTopoToBody = baseFrame.getStaticTransformTo(bodyFrame, date);
         final FieldVector3D<T>        originBeforeDisplacement     = staticTopoToBody.transformPosition(new FieldVector3D<>(x, y, z));
         return originBeforeDisplacement.add(computeDisplacement(absoluteDate, originBeforeDisplacement.toVector3D()));
     }
 
 }