/* Copyright 2022-2026 Thales Alenia Space
    * 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.time.clocks;
  
  import java.util.Arrays;
  import java.util.List;
  
  import org.hipparchus.CalculusFieldElement;
  import org.orekit.errors.OrekitException;
  import org.orekit.errors.OrekitMessages;
  import org.orekit.time.FieldAbsoluteDate;
  import org.orekit.time.FieldTimeStamped;
  
  /**
   * Container for time stamped clock offset.
   *
   * @param <T> type of the field elements
   * @author Luc Maisonobe
   * @since 12.1
   */
  public class FieldClockOffset<T extends CalculusFieldElement<T>> implements FieldTimeStamped<T> {
  
      /** Date. */
      private final FieldAbsoluteDate<T> date;
  
      /** Clock bias. */
      private final T bias;
  
      /** Clock rate. */
      private final T rate;
  
      /** Clock acceleration. */
      private final T acceleration;
  
      /** Simple constructor.
       *
       * @param date         date
       * @param bias         clock bias
       * @param rate         clock rate (can be set to {@code null} if unknown)
       * @param acceleration clock acceleration (can be set to {@code null} if
       *                     unknown)
       */
      public FieldClockOffset(final FieldAbsoluteDate<T> date, final T bias,
              final T rate, final T acceleration) {
          this.date = date;
          this.bias = bias;
          this.rate = rate;
          this.acceleration = acceleration;
      }
  
      /** Simple constructor.
       *
       * @param date         date
       * @param terms        array of clock terms (bias, rate, acceleration)
       */
      public FieldClockOffset(final FieldAbsoluteDate<T> date, final T[] terms) {
          this(date, Arrays.asList(terms));
      }
  
      /** Simple constructor.
       *
       * @param date         date
       * @param terms        list of clock terms (bias, rate, acceleration)
       */
      public FieldClockOffset(final FieldAbsoluteDate<T> date, final List<T> terms) {
          this.date = date;
  
          if (!terms.isEmpty()) {
              this.bias = terms.getFirst();
          } else {
              this.bias = date.getField().getZero();
          }
          if (terms.size() >= 2) {
              this.rate = terms.get(1);
          } else {
              this.rate = date.getField().getZero();
          }
          if (terms.size() == 3) {
              this.acceleration = terms.get(2);
          } else {
              this.acceleration = date.getField().getZero();
          }
          if (terms.size() > 3) {
              throw new OrekitException(OrekitMessages.CANNOT_PARSE_DATA);
          }
     }
 
     /**
      * Add another offset to the instance.
      * <p>
      * The instance is not modified, a new instance is created
      * </p>
      *
      * @param other offset to add (date part will be ignored)
      * @return instance + other, at instance date
      * @since 14.0
      */
     public FieldClockOffset<T> add(final FieldClockOffset<T> other) {
         return new FieldClockOffset<>(date,
                 bias.add(other.bias),
                 rate.add(other.rate),
                 acceleration.add(other.acceleration));
     }
 
     /** Subtract another offset from the instance.
      * <p>
      * The instance is not modified, a new instance is created
      * </p>
      *
      * @param other offset to subtract (date part will be ignored)
      * @return instance - other, at instance date
      * @since 14.0
      */
     public FieldClockOffset<T> subtract(final FieldClockOffset<T> other) {
         return new FieldClockOffset<>(date,
                 bias.subtract(other.bias),
                 rate.subtract(other.rate),
                 acceleration.subtract(other.acceleration));
     }
 
     /** {@inheritDoc} */
     @Override
     public FieldAbsoluteDate<T> getDate() {
         return date;
     }
 
     /** Get bias.
      * @return bias
      */
     public T getBias() {
         return bias;
     }
 
     /** Get rate.
      * @return rate ({@code null} if unknown)
      */
     public T getRate() {
         return rate;
     }
 
     /** Get acceleration.
      * @return acceleration ({@code null} if unknown)
      */
     public T getAcceleration() {
         return acceleration;
     }
 
     /** Negate instance.
      * <p>
      * The instance is not modified, a new instance is created
      * </p>
      *
      * @return instance - other, at instance date
      * @since 14.0
      */
     public FieldClockOffset<T> negate() {
         return new FieldClockOffset<>(getDate(), bias.negate(), rate.negate(), acceleration.negate());
     }
 
 }