/* 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.forces.gravity.potential;
  
  import org.hipparchus.util.FastMath;
  import org.hipparchus.util.MathUtils;
  import org.hipparchus.util.SinCos;
  import org.orekit.time.AbsoluteDate;
  
  /** Simple implementation of {@link RawSphericalHarmonicsProvider} for pulsating gravity fields.
   * @author Luc Maisonobe
   * @since 6.0
   * @deprecated as of 11.1, replaced by {@link PiecewiseSphericalHarmonics}
   */
  @Deprecated
  class PulsatingSphericalHarmonics implements RawSphericalHarmonicsProvider {
  
      /** Underlying part of the field. */
      private final RawSphericalHarmonicsProvider provider;
  
      /** Pulsation (rad/s). */
      private final double pulsation;
  
      /** Converter from triangular to flatten array.
       * @since 11.1
       */
      private final Flattener flattener;
  
      /** Cosine component of the cosine coefficients. */
      private final double[] cosC;
  
      /** Sine component of the cosine coefficients. */
      private final double[] sinC;
  
      /** Cosine component of the sine coefficients. */
      private final double[] cosS;
  
      /** Sine component of the sine coefficients. */
      private final double[] sinS;
  
      /** Simple constructor.
       * @param provider underlying part of the field
       * @param period period of the pulsation (s)
       * @param cosC cosine component of the cosine coefficients
       * @param sinC sine component of the cosine coefficients
       * @param cosS cosine component of the sine coefficients
       * @param sinS sine component of the sine coefficients
       * @deprecated as of 11.1, replaced by {@link #PulsatingSphericalHarmonics(RawSphericalHarmonicsProvider,
       * double, Flattener, double[], double[], double[], double[])}
       */
      @Deprecated
      PulsatingSphericalHarmonics(final RawSphericalHarmonicsProvider provider,
                                  final double period,
                                  final double[][] cosC, final double[][] sinC,
                                  final double[][] cosS, final double[][] sinS) {
          this(provider, period, buildFlattener(cosC),
               buildFlattener(cosC).flatten(cosC), buildFlattener(sinC).flatten(sinC),
               buildFlattener(cosS).flatten(cosS), buildFlattener(sinS).flatten(sinS));
      }
  
      /** Simple constructor.
       * @param provider underlying part of the field
       * @param period period of the pulsation (s)
       * @param flattener flattener from triangular to flatten array
       * @param cosC cosine component of the cosine coefficients
       * @param sinC sine component of the cosine coefficients
       * @param cosS cosine component of the sine coefficients
       * @param sinS sine component of the sine coefficients
       * @since 11.1
       */
      PulsatingSphericalHarmonics(final RawSphericalHarmonicsProvider provider,
                                  final double period, final Flattener flattener,
                                  final double[] cosC, final double[] sinC,
                                  final double[] cosS, final double[] sinS) {
          this.provider  = provider;
          this.pulsation = MathUtils.TWO_PI / period;
          this.flattener = flattener;
          this.cosC      = cosC.clone();
          this.sinC      = sinC.clone();
          this.cosS      = cosS.clone();
          this.sinS      = sinS.clone();
      }
  
      /** Get a flattener for a triangular array.
       * @param triangular triangular array to flatten
      * @return flattener suited for triangular array dimensions
      * @since 11.1
      */
     private static Flattener buildFlattener(final double[][] triangular) {
         return new Flattener(triangular.length - 1, triangular[triangular.length - 1].length - 1);
     }
 
     /** {@inheritDoc} */
     public int getMaxDegree() {
         return FastMath.max(flattener.getDegree(), provider.getMaxDegree());
     }
 
     /** {@inheritDoc} */
     public int getMaxOrder() {
         return FastMath.max(flattener.getOrder(), provider.getMaxOrder());
     }
 
     /** {@inheritDoc} */
     public double getMu() {
         return provider.getMu();
     }
 
     /** {@inheritDoc} */
     public double getAe() {
         return provider.getAe();
     }
 
     /** {@inheritDoc} */
     public AbsoluteDate getReferenceDate() {
         return provider.getReferenceDate();
     }
 
     /** {@inheritDoc} */
     @Deprecated
     public double getOffset(final AbsoluteDate date) {
         return provider.getOffset(date);
     }
 
     /** {@inheritDoc} */
     public TideSystem getTideSystem() {
         return provider.getTideSystem();
     }
 
     @Override
     @Deprecated
     public RawSphericalHarmonics onDate(final AbsoluteDate date) {
         //raw (constant) harmonics
         final RawSphericalHarmonics raw = provider.onDate(date);
         //phase angle, will loose precision for large offsets
         final double alpha = pulsation * provider.getOffset(date);
         //pre-compute transcendental functions
         final SinCos scAlpha = FastMath.sinCos(alpha);
         return new RawSphericalHarmonics() {
 
             @Override
             public AbsoluteDate getDate() {
                 return date;
             }
 
             /** {@inheritDoc} */
             public double getRawCnm(final int n, final int m) {
 
                 // retrieve the underlying part of the coefficient
                 double cnm = raw.getRawCnm(n, m);
 
                 if (flattener.withinRange(n, m)) {
                     // add pulsation
                     cnm += cosC[flattener.index(n, m)] * scAlpha.cos() + sinC[flattener.index(n, m)] * scAlpha.sin();
                 }
 
                 return cnm;
             }
 
             /** {@inheritDoc} */
             public double getRawSnm(final int n, final int m) {
 
                 // retrieve the constant part of the coefficient
                 double snm = raw.getRawSnm(n, m);
 
                 if (flattener.withinRange(n, m)) {
                     // add pulsation
                     snm += cosS[flattener.index(n, m)] * scAlpha.cos() + sinS[flattener.index(n, m)] * scAlpha.sin();
                 }
 
                 return snm;
             }
 
         };
     }
 
 }