/* Copyright 2002-2025 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
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   */
  package org.orekit.frames;
  
  import org.hipparchus.CalculusFieldElement;
  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.RotationConvention;
  import org.hipparchus.geometry.euclidean.threed.RotationOrder;
  import org.hipparchus.geometry.euclidean.threed.Vector3D;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.time.FieldAbsoluteDate;
  import org.orekit.utils.Constants;
  
  
  /** International Terrestrial Reference Frame.
   * <p> Handles pole motion effects and depends on {@link TIRFProvider}, its
   * parent frame.</p>
   * @author Luc Maisonobe
   */
  class ITRFProvider implements EOPBasedTransformProvider {
  
      /** S' rate in radians per julian century.
       * Approximately -47 microarcsecond per julian century (Lambert and Bizouard, 2002)
       */
      private static final double S_PRIME_RATE = -47e-6 * Constants.ARC_SECONDS_TO_RADIANS;
  
      /** EOP history. */
      private final EOPHistory eopHistory;
  
      /** Simple constructor.
       * @param eopHistory EOP history
       */
      ITRFProvider(final EOPHistory eopHistory) {
          this.eopHistory = eopHistory;
      }
  
      /** {@inheritDoc} */
      @Override
      public EOPHistory getEOPHistory() {
          return eopHistory;
      }
  
      /** {@inheritDoc} */
      @Override
      public ITRFProvider getNonInterpolatingProvider() {
          return new ITRFProvider(eopHistory.getEOPHistoryWithoutCachedTidalCorrection());
      }
  
      /** {@inheritDoc} */
      @Override
      public Transform getTransform(final AbsoluteDate date) {
  
          // offset from J2000 epoch in Julian centuries
          final double tts = date.durationFrom(eopHistory.getTimeScales().getJ2000Epoch());
          final double ttc =  tts / Constants.JULIAN_CENTURY;
  
          // pole correction parameters
          final PoleCorrection eop = eopHistory.getPoleCorrection(date);
  
          // pole motion in terrestrial frame
          final Rotation wRot = new Rotation(RotationOrder.XYZ, RotationConvention.FRAME_TRANSFORM,
                                             eop.getYp(), eop.getXp(), -S_PRIME_RATE * ttc);
  
          // combined effects
          final Rotation combined = wRot.revert();
  
          // set up the transform from parent TIRF
          return new Transform(date, combined, Vector3D.ZERO);
  
      }
  
      /** {@inheritDoc} */
      @Override
      public <T extends CalculusFieldElement<T>> FieldTransform<T> getTransform(final FieldAbsoluteDate<T> date) {
  
          // offset from J2000 epoch in Julian centuries
          final T tts = date.durationFrom(eopHistory.getTimeScales().getJ2000Epoch());
          final T ttc =  tts.divide(Constants.JULIAN_CENTURY);
  
          // pole correction parameters
          final FieldPoleCorrection<T> eop = eopHistory.getPoleCorrection(date);
  
          // pole motion in terrestrial frame
         final FieldRotation<T> wRot = new FieldRotation<>(RotationOrder.XYZ, RotationConvention.FRAME_TRANSFORM,
                                                           eop.getYp(),
                                                           eop.getXp(),
                                                           ttc.multiply(-S_PRIME_RATE));
 
         // combined effects
         final FieldRotation<T> combined = wRot.revert();
 
         // set up the transform from parent TIRF
         return new FieldTransform<>(date, combined, FieldVector3D.getZero(date.getField()));
 
     }
 
 }