/* Copyright 2002-2020 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.integration;
  
  import org.orekit.attitudes.AttitudeProvider;
  import org.orekit.frames.Frame;
  import org.orekit.orbits.OrbitType;
  import org.orekit.orbits.PositionAngle;
  import org.orekit.propagation.PropagationType;
  import org.orekit.propagation.SpacecraftState;
  import org.orekit.time.AbsoluteDate;
  
  /** This class maps between raw double elements and {@link SpacecraftState} instances.
   * @author Luc Maisonobe
   * @since 6.0
   */
  public abstract class StateMapper {
  
      /** Reference date. */
      private final AbsoluteDate referenceDate;
  
      /** Propagation orbit type. */
      private final OrbitType orbitType;
  
      /** Position angle type. */
      private final PositionAngle angleType;
  
      /** Attitude provider. */
      private final AttitudeProvider attitudeProvider;
  
      /** Central attraction coefficient. */
      private final double mu;
  
      /** Inertial frame. */
      private final Frame frame;
  
      /** Simple constructor.
       * <p>
       * The position parameter type is meaningful only if {@link
       * #getOrbitType() propagation orbit type}
       * support it. As an example, it is not meaningful for propagation
       * in {@link OrbitType#CARTESIAN Cartesian} parameters.
       * </p>
       * @param referenceDate reference date
       * @param mu central attraction coefficient (m³/s²)
       * @param orbitType orbit type to use for mapping, null for
       * propagating using {@link org.orekit.utils.AbsolutePVCoordinates AbsolutePVCoordinates}
       * rather than {@link org.orekit.orbits Orbit}
       * @param positionAngleType angle type to use for propagation
       * @param attitudeProvider attitude provider
       * @param frame inertial frame
       */
      protected StateMapper(final AbsoluteDate referenceDate, final double mu,
                            final OrbitType orbitType, final PositionAngle positionAngleType,
                            final AttitudeProvider attitudeProvider, final Frame frame) {
          this.referenceDate    = referenceDate;
          this.mu               = mu;
          this.orbitType        = orbitType;
          this.angleType        = positionAngleType;
          this.attitudeProvider = attitudeProvider;
          this.frame            = frame;
      }
  
      /** Get reference date.
       * @return reference date
       */
      public AbsoluteDate getReferenceDate() {
          return referenceDate;
      }
  
      /** Get propagation parameter type.
       * @return orbit type used for propagation
       */
      public OrbitType getOrbitType() {
          return orbitType;
      }
  
      /** Set position angle type.
       */
      public void setPositionAngleType() {
      }
  
      /** Get propagation parameter type.
       * @return angle type to use for propagation
       */
     public PositionAngle getPositionAngleType() {
         return angleType;
     }
 
     /** Get the central attraction coefficient μ.
      * @return mu central attraction coefficient (m³/s²)
      */
     public double getMu() {
         return mu;
     }
 
     /** Get the inertial frame.
      * @return inertial frame
      */
     public Frame getFrame() {
         return frame;
     }
 
     /** Get the attitude provider.
      * @return attitude provider
      */
     public AttitudeProvider getAttitudeProvider() {
         return attitudeProvider;
     }
 
     /** Map the raw double time offset to a date.
      * @param t date offset
      * @return date
      */
     public AbsoluteDate mapDoubleToDate(final double t) {
         return referenceDate.shiftedBy(t);
     }
 
     /**
      * Map the raw double time offset to a date.
      *
      * @param t    date offset
      * @param date The expected date.
      * @return {@code date} if it is the same time as {@code t} to within the
      * lower precision of the latter. Otherwise a new date is returned that
      * corresponds to time {@code t}.
      */
     public AbsoluteDate mapDoubleToDate(final double t,
                                         final AbsoluteDate date) {
         if (date.durationFrom(referenceDate) == t) {
             return date;
         } else {
             return mapDoubleToDate(t);
         }
     }
 
     /** Map a date to a raw double time offset.
      * @param date date
      * @return time offset
      */
     public double mapDateToDouble(final AbsoluteDate date) {
         return date.durationFrom(referenceDate);
     }
 
     /** Map the raw double components to a spacecraft state.
      * @param t date offset
      * @param y state components
      * @param yDot time derivatives of the state components (null if unknown, in which case Keplerian motion is assumed)
      * @param type type of the elements used to build the state (mean or osculating).
      * @return spacecraft state
      */
     public SpacecraftState mapArrayToState(final double t, final double[] y, final double[] yDot, final PropagationType type) {
         return mapArrayToState(mapDoubleToDate(t), y, yDot, type);
     }
 
     /** Map the raw double components to a spacecraft state.
      * @param date of the state components
      * @param y state components
      * @param yDot time derivatives of the state components (null if unknown, in which case Keplerian motion is assumed)
      * @param type type of the elements used to build the state (mean or osculating).
      * @return spacecraft state
      */
     public abstract SpacecraftState mapArrayToState(AbsoluteDate date, double[] y, double[] yDot, PropagationType type);
 
     /** Map a spacecraft state to raw double components.
      * @param state state to map
      * @param y placeholder where to put the components
      * @param yDot placeholder where to put the components derivatives
      */
     public abstract void mapStateToArray(SpacecraftState state, double[] y, double[] yDot);
 
 }