/* Copyright 2002-2026 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.propagation.semianalytical.dsst.forces;
  
  import org.hipparchus.CalculusFieldElement;
  import org.orekit.forces.gravity.potential.UnnormalizedSphericalHarmonicsProvider;
  import org.orekit.frames.Frame;
  import org.orekit.propagation.semianalytical.dsst.utilities.FieldAuxiliaryElements;
  import org.orekit.time.AbsoluteDate;
  
  /**
   * This class is a container for the common "field" parameters used in {@link DSSTZonal}.
   * <p>
   * It performs parameters initialization at each integration step for the Zonal contribution
   * to the central body gravitational perturbation.
   * </p>
   * @author Bryan Cazabonne
   * @since 10.0
   * @param <T> type of the field elements
   */
  public class FieldDSSTZonalContext<T extends CalculusFieldElement<T>> extends FieldDSSTGravityContext<T> {
  
      /** &Chi;³ = 1 / B³. */
      private final T chi3;
  
      // Short period terms
      /** h * k. */
      private final T hk;
      /** k² - h². */
      private final T k2mh2;
      /** (k² - h²) / 2. */
      private final T k2mh2o2;
      /** 1 / (n² * a²). */
      private final T oon2a2;
      /** 1 / (n² * a) . */
      private final T oon2a;
      /** χ³ / (n² * a). */
      private final T x3on2a;
      /** χ / (n² * a²). */
      private final T xon2a2;
      /** (C * χ) / ( 2 * n² * a² ). */
      private final T cxo2n2a2;
      /** (χ²) / (n² * a² * (χ + 1 ) ). */
      private final T x2on2a2xp1;
      /** B * B. */
      private final T BB;
  
      /** Constructor with central body frame potentially different from orbit frame.
       *
       * @param auxiliaryElements auxiliary elements related to the current orbit
       * @param centralBodyFrame  rotating body frame
       * @param provider          provider for spherical harmonics
       * @param parameters        values of the force model parameters (only 1 values
       * for each parameters corresponding to state date) obtained by calling the extract
       * parameter method {@link #extractParameters(double[], AbsoluteDate)}
       * to selected the right value for state date or by getting the parameters for a specific date
       * @since 12.2
       */
      FieldDSSTZonalContext(final FieldAuxiliaryElements<T> auxiliaryElements,
                            final Frame centralBodyFrame,
                            final UnnormalizedSphericalHarmonicsProvider provider,
                            final T[] parameters) {
  
          super(auxiliaryElements, centralBodyFrame, provider, parameters);
  
          // Chi3
          final T chi = getChi();
          this.chi3 = chi.multiply(getChi2());
  
          // Short period terms
          // -----
  
          // h * k.
          hk = auxiliaryElements.getH().multiply(auxiliaryElements.getK());
          // k² - h².
          k2mh2 = auxiliaryElements.getK().multiply(auxiliaryElements.getK()).subtract(auxiliaryElements.getH().multiply(auxiliaryElements.getH()));
          // (k² - h²) / 2.
          k2mh2o2 = k2mh2.divide(2.);
          // 1 / (n² * a²) = 1 / (n * A)
          oon2a2 = (getA().multiply(getMeanMotion())).reciprocal();
          // 1 / (n² * a) = a / (n * A)
          oon2a = auxiliaryElements.getSma().multiply(oon2a2);
          // χ³ / (n² * a)
          x3on2a = chi3.multiply(oon2a);
          // χ / (n² * a²)
         xon2a2 = chi.multiply(oon2a2);
         // (C * χ) / ( 2 * n² * a² )
         cxo2n2a2 = xon2a2.multiply(auxiliaryElements.getC()).divide(2.);
         // (χ²) / (n² * a² * (χ + 1 ) )
         x2on2a2xp1 = xon2a2.multiply(chi).divide(chi.add(1.));
         // B * B
         BB = auxiliaryElements.getB().multiply(auxiliaryElements.getB());
     }
 
 
     /** Getter for the &Chi;³.
      * @return the &Chi;³
      */
     public T getChi3() {
         return chi3;
     }
 
     /** Get h * k.
      * @return hk
      */
     public T getHK() {
         return hk;
     }
 
     /** Get k² - h².
      * @return k2mh2
      */
     public T getK2MH2() {
         return k2mh2;
     }
 
     /** Get (k² - h²) / 2.
      * @return k2mh2o2
      */
     public T getK2MH2O2() {
         return k2mh2o2;
     }
 
     /** Get 1 / (n² * a²).
      * @return oon2a2
      */
     public T getOON2A2() {
         return oon2a2;
     }
 
     /** Get χ³ / (n² * a).
      * @return x3on2a
      */
     public T getX3ON2A() {
         return x3on2a;
     }
 
     /** Get χ / (n² * a²).
      * @return xon2a2
      */
     public T getXON2A2() {
         return xon2a2;
     }
 
     /** Get (C * χ) / ( 2 * n² * a² ).
      * @return cxo2n2a2
      */
     public T getCXO2N2A2() {
         return cxo2n2a2;
     }
 
     /** Get (χ²) / (n² * a² * (χ + 1 ) ).
      * @return x2on2a2xp1
      */
     public T getX2ON2A2XP1() {
         return x2on2a2xp1;
     }
 
     /** Get B * B.
      * @return BB
      */
     public T getBB() {
         return BB;
     }
 
 }