/* 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
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   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
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  package org.orekit.propagation;
  
  import java.util.Collection;
  import java.util.List;
  
  import org.hipparchus.CalculusFieldElement;
  import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
  import org.orekit.attitudes.AttitudeProvider;
  import org.orekit.frames.FieldKinematicTransform;
  import org.orekit.frames.Frame;
  import org.orekit.propagation.events.FieldEventDetector;
  import org.orekit.propagation.sampling.FieldOrekitFixedStepHandler;
  import org.orekit.propagation.sampling.FieldOrekitStepHandler;
  import org.orekit.propagation.sampling.FieldStepHandlerMultiplexer;
  import org.orekit.time.FieldAbsoluteDate;
  import org.orekit.utils.FieldPVCoordinatesProvider;
  import org.orekit.utils.TimeStampedFieldPVCoordinates;
  
  /** This interface provides a way to propagate an orbit at any time.
   *
   * <p>This interface is the top-level abstraction for orbit propagation.
   * It only allows propagation to a predefined date.
   * It is implemented by analytical models which have no time limit,
   * by orbit readers based on external data files, by numerical integrators
   * using rich force models and by continuous models built after numerical
   * integration has been completed and dense output data as been
   * gathered.</p>
   * @param <T> the type of the field elements
  
   * @author Luc Maisonobe
   * @author V&eacute;ronique Pommier-Maurussane
   *
   */
  
  public interface FieldPropagator<T extends CalculusFieldElement<T>> extends FieldPVCoordinatesProvider<T> {
  
      /** Default mass. */
      double DEFAULT_MASS = 1000.0;
  
      /** Get the multiplexer holding all step handlers.
       * @return multiplexer holding all step handlers
       * @since 11.0
       */
      FieldStepHandlerMultiplexer<T> getMultiplexer();
  
      /** Remove all step handlers.
       * <p>This convenience method is equivalent to call {@code getMultiplexer().clear()}</p>
       * @see #getMultiplexer()
       * @see FieldStepHandlerMultiplexer#clear()
       * @since 11.0
       */
      default void clearStepHandlers() {
          getMultiplexer().clear();
      }
  
      /** Set a single handler for fixed stepsizes.
       * <p>This convenience method is equivalent to call {@code getMultiplexer().clear()}
       * followed by {@code getMultiplexer().add(h, handler)}</p>
       * @param h fixed stepsize (s)
       * @param handler handler called at the end of each finalized step
       * @see #getMultiplexer()
       * @see FieldStepHandlerMultiplexer#add(CalculusFieldElement, FieldOrekitFixedStepHandler)
       * @since 11.0
       */
      default void setStepHandler(final T h, final FieldOrekitFixedStepHandler<T> handler) {
          getMultiplexer().clear();
          getMultiplexer().add(h, handler);
      }
  
      /** Set a single handler for variable stepsizes.
       * <p>This convenience method is equivalent to call {@code getMultiplexer().clear()}
       * followed by {@code getMultiplexer().add(handler)}</p>
       * @param handler handler called at the end of each finalized step
       * @see #getMultiplexer()
       * @see FieldStepHandlerMultiplexer#add(FieldOrekitStepHandler)
       * @since 11.0
       */
      default void setStepHandler(final FieldOrekitStepHandler<T> handler) {
          getMultiplexer().clear();
          getMultiplexer().add(handler);
      }
  
      /**
      * Set up an ephemeris generator that will monitor the propagation for building
      * an ephemeris from it once completed.
      *
      * <p>
      * This generator can be used when the user needs fast random access to the orbit
      * state at any time between the initial and target times. A typical example is the
      * implementation of search and iterative algorithms that may navigate forward and
      * backward inside the propagation range before finding their result even if the
      * propagator used is integration-based and only goes from one initial time to one
      * target time.
      * </p>
      * <p>
      * Beware that when used with integration-based propagators, the generator will
      * store <strong>all</strong> intermediate results. It is therefore memory intensive
      * for long integration-based ranges and high precision/short time steps. When
      * used with analytical propagators, the generator only stores start/stop time
      * and a reference to the analytical propagator itself to call it back as needed,
      * so it is less memory intensive.
      * </p>
      * <p>
      * The returned ephemeris generator will be initially empty, it will be filled
      * with propagation data when a subsequent call to either {@link #propagate(FieldAbsoluteDate)
      * propagate(target)} or {@link #propagate(FieldAbsoluteDate, FieldAbsoluteDate)
      * propagate(start, target)} is called. The proper way to use this method is
      * therefore to do:
      * </p>
      * <pre>
      *   FieldEphemerisGenerator&lt;T&gt; generator = propagator.getEphemerisGenerator();
      *   propagator.propagate(target);
      *   FieldBoundedPropagator&lt;T&gt; ephemeris = generator.getGeneratedEphemeris();
      * </pre>
      * @return ephemeris generator
      */
     FieldEphemerisGenerator<T> getEphemerisGenerator();
 
     /** Get the propagator initial state.
      * @return initial state
      */
     FieldSpacecraftState<T> getInitialState();
 
     /** Reset the propagator initial state.
      * @param state new initial state to consider
      */
     void resetInitialState(FieldSpacecraftState<T> state);
 
     /** Add a set of user-specified data to be computed along with the orbit propagation.
      * @param additionalDataProvider provider for additional data
      */
     void addAdditionalDataProvider(FieldAdditionalDataProvider<?, T> additionalDataProvider);
 
     /** Get an unmodifiable list of providers for additional data.
      * @return providers for the additional states
      */
     List<FieldAdditionalDataProvider<?, T>> getAdditionalDataProviders();
 
     /** Check if an additional data is managed.
      * <p>
      * Managed data are the ones for which the propagators know how to compute
      * its evolution. They correspond to additional data for which an
      * {@link FieldAdditionalDataProvider additional data provider} has been registered
      * by calling the {@link #addAdditionalDataProvider(FieldAdditionalDataProvider)
      * addAdditionalDataProvider} method. If the propagator is an {@link
      * org.orekit.propagation.integration.FieldAbstractIntegratedPropagator integrator-based
      * propagator}, the states for which a set of {@link
      * org.orekit.propagation.integration.FieldAdditionalDerivativesProvider additional derivatives
      * provider} has been registered by calling the {@link
      * org.orekit.propagation.integration.FieldAbstractIntegratedPropagator#addAdditionalDerivativesProvider(
      * org.orekit.propagation.integration.FieldAdditionalDerivativesProvider) addAdditionalDerivativesProvider}
      * method are also counted as managed additional states.
      * </p>
      * <p>
      * Additional data that are present in the {@link #getInitialState() initial state}
      * but have no evolution method registered are <em>not</em> considered as managed data.
      * These unmanaged additional data are not lost during propagation, though. Their
      * value are piecewise constant between state resets that may change them if some
      * event handler {@link
      * org.orekit.propagation.events.handlers.FieldEventHandler#resetState(FieldEventDetector,
      * FieldSpacecraftState) resetState} method is called at an event occurrence and happens
      * to change the unmanaged additional data.
      * </p>
      * @param name name of the additional data
      * @return true if the additional data is managed
      */
     boolean isAdditionalDataManaged(String name);
 
     /** Get all the names of all managed data.
      * @return names of all managed data
      */
     String[] getManagedAdditionalData();
 
     /** Add an event detector.
      * @param detector event detector to add
      * @see #clearEventsDetectors()
      * @see #getEventDetectors()
      * @param <D> class type for the generic version
      */
     <D extends FieldEventDetector<T>> void addEventDetector(D detector);
 
     /** Get all the events detectors that have been added.
      * @return an unmodifiable collection of the added detectors
      * @see #addEventDetector(FieldEventDetector)
      * @see #clearEventsDetectors()
      */
     Collection<FieldEventDetector<T>> getEventDetectors();
 
     /** Remove all events detectors.
      * @see #addEventDetector(FieldEventDetector)
      * @see #getEventDetectors()
      */
     void clearEventsDetectors();
 
     /** Get attitude provider.
      * @return attitude provider
      */
     AttitudeProvider getAttitudeProvider();
 
     /** Set attitude provider.
      * @param attitudeProvider attitude provider
      */
     void setAttitudeProvider(AttitudeProvider attitudeProvider);
 
     /** Get the frame in which the orbit is propagated.
      * <p>
      * The propagation frame is the definition frame of the initial
      * state, so this method should be called after this state has
      * been set, otherwise it may return null.
      * </p>
      * @return frame in which the orbit is propagated
      * @see #resetInitialState(FieldSpacecraftState)
      */
     Frame getFrame();
 
     /** Propagate towards a target date.
      * <p>Simple propagators use only the target date as the specification for
      * computing the propagated state. More feature rich propagators can consider
      * other information and provide different operating modes or G-stop
      * facilities to stop at pinpointed events occurrences. In these cases, the
      * target date is only a hint, not a mandatory objective.</p>
      * @param target target date towards which orbit state should be propagated
      * @return propagated state
      */
     FieldSpacecraftState<T> propagate(FieldAbsoluteDate<T> target);
 
     /** Propagate from a start date towards a target date.
      * <p>Those propagators use a start date and a target date to
      * compute the propagated state. For propagators using event detection mechanism,
      * if the provided start date is different from the initial state date, a first,
      * simple propagation is performed, without processing any event computation.
      * Then complete propagation is performed from start date to target date.</p>
      * @param start start date from which orbit state should be propagated
      * @param target target date to which orbit state should be propagated
      * @return propagated state
      */
     FieldSpacecraftState<T> propagate(FieldAbsoluteDate<T> start, FieldAbsoluteDate<T> target);
 
     /** {@inheritDoc} */
     @Override
     default TimeStampedFieldPVCoordinates<T> getPVCoordinates(final FieldAbsoluteDate<T> date, final Frame frame) {
         return propagate(date).getPVCoordinates(frame);
     }
 
     /** {@inheritDoc} */
     @Override
     default FieldVector3D<T> getVelocity(final FieldAbsoluteDate<T> date, final Frame frame) {
         final FieldSpacecraftState<T> state = propagate(date);
         if (frame == getFrame()) {
             return state.getVelocity();
         }
         final FieldKinematicTransform<T> kinematicTransform = getFrame().getKinematicTransformTo(frame, date);
         return kinematicTransform.transformOnlyPV(state.getPVCoordinates()).getVelocity();
     }
 
     /** {@inheritDoc} */
     @Override
     default FieldVector3D<T> getPosition(final FieldAbsoluteDate<T> date, final Frame frame) {
         return propagate(date).getPosition(frame);
     }
 
 }