/* Copyright 2024-2025 The Johns Hopkins University Applied Physics Laboratory
    * 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.
    * ADS 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.files.iirv;
  
  import org.orekit.errors.OrekitInternalError;
  import org.orekit.files.general.EphemerisFile;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.utils.TimeStampedPVCoordinates;
  
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Class for associating a the {@link IIRVEphemeris} ephemeris state data (obtained from an {@link IIRVMessage})
   * to a single satellite, identified by its IIRV {@link org.orekit.files.iirv.terms.VehicleIdCodeTerm}.
   */
  public class IIRVEphemerisFile implements EphemerisFile<TimeStampedPVCoordinates, IIRVSegment> {
  
      /** Unmodifiable mapping with a single key-value pair from satellite id to ephemeris. */
      private final Map<String, IIRVEphemerisFile.IIRVEphemeris> satellites;
  
      /**
       * Constructs a {@link IIRVEphemerisFile} instance.
       *
       * @param ephemeris IIRV ephemeris data.
       */
      public IIRVEphemerisFile(final IIRVEphemerisFile.IIRVEphemeris ephemeris) {
          final Map<String, IIRVEphemerisFile.IIRVEphemeris> tempMap = new HashMap<>();
          tempMap.put(ephemeris.getId(), ephemeris);
          this.satellites = Collections.unmodifiableMap(tempMap);
      }
  
      /**
       * Constructs a {@link IIRVEphemerisFile} instance from a {@link IIRVMessage}.
       *
       * @param mu                   gravitational parameter (m^3/s^2)
       * @param interpolationSamples number of samples to use in interpolation
       * @param startYear            Year associated with the beginning of the IIRV message
       * @param iirvMessage          IIRV message
       */
      public IIRVEphemerisFile(final double mu,
                               final int interpolationSamples,
                               final int startYear,
                               final IIRVMessage iirvMessage) {
          this(new IIRVEphemerisFile.IIRVEphemeris(new IIRVSegment(mu, interpolationSamples, startYear, iirvMessage)));
      }
  
      /**
       * Constructs a {@link IIRVEphemerisFile} instance from a {@link IIRVMessage} with default values.
       * <p>
       * See {@link IIRVSegment#IIRVSegment(int, IIRVMessage)} for default value information.
       *
       * @param startYear   Year associated with the beginning of the IIRV message
       * @param iirvMessage IIRV message
       */
      public IIRVEphemerisFile(final int startYear, final IIRVMessage iirvMessage) {
          this(new IIRVEphemerisFile.IIRVEphemeris(new IIRVSegment(startYear, iirvMessage)));
      }
  
  
      /**
       * {@inheritDoc}
       * <p>
       * STK ephemeris files define ephemeris for a single satellite, so the returned
       * map will have a single entry.
       * </p>
       */
      @Override
      public Map<String, IIRVEphemerisFile.IIRVEphemeris> getSatellites() {
          return satellites;
      }
  
      /**
       * Gets the {@link IIRVEphemeris} associated with this file.
       *
       * @return {@link IIRVEphemeris} associated with this file.
       */
      public IIRVEphemeris getIIRVEphemeris() {
          if (satellites.size() != 1) {
              // This should never happen
              throw new OrekitInternalError(null);
          }
          return satellites.values().iterator().next();
     }
 
     /**
      * Gets the IIRV message containing the ephemeris data.
      *
      * @return IIRVMessage containing the ephemeris data.
      */
     public IIRVMessage getIIRV() {
         return getIIRVEphemeris().getIIRV();
     }
 
     /**
      * Gets the start year for this file.
      *
      * @return start year for this file.
      */
     public int getStartYear() {
         return getIIRVEphemeris().getStartYear();
     }
 
     /**
      * Ephemeris from an IIRV file.
      */
     public static class IIRVEphemeris implements SatelliteEphemeris<TimeStampedPVCoordinates, IIRVSegment> {
 
         /** Ephemeris segment. */
         private final IIRVSegment segment;
 
         /**
          * Constructs a {@link IIRVSegment} instance.
          * <p>
          * An IIRV file contains ephemeris data for a single satellite; thus each {@link IIRVEphemeris} instance
          * contains only a single {@link IIRVSegment}.
          *
          * @param segment ephemeris segments
          */
         public IIRVEphemeris(final IIRVSegment segment) {
             this.segment = segment;
         }
 
         /** {@inheritDoc} */
         @Override
         public String getId() {
             return segment.getIIRVMessage().getSatelliteID();
         }
 
         /** {@inheritDoc} */
         @Override
         public double getMu() {
             return segment.getMu();
         }
 
         /**
          * Get the {@link IIRVSegment} for this satellite.
          *
          * @return {@link IIRVSegment} for this satellite.
          * @see #getSegment()
          */
         public IIRVSegment getSegment() {
             return segment;
         }
 
         /** {@inheritDoc} */
         @Override
         public List<IIRVSegment> getSegments() {
             return Collections.singletonList(segment);
         }
 
         /** {@inheritDoc} */
         @Override
         public AbsoluteDate getStart() {
             return segment.getStart();
         }
 
         /** {@inheritDoc} */
         @Override
         public AbsoluteDate getStop() {
             return segment.getStop();
         }
 
         /**
          * Gets the {@link IIRVMessage} containing the ephemeris data for this object's {@link IIRVSegment}.
          *
          * @return {@link IIRVMessage} containing the ephemeris data for this object's {@link IIRVSegment}.
          */
         public IIRVMessage getIIRV() {
             return segment.getIIRVMessage();
         }
 
         /**
          * Gets the start year of the ephemeris data.
          *
          * @return start year of the ephemeris data
          */
         public int getStartYear() {
             return segment.getStartYear();
         }
 
     }
 
 }