/* 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
   *
   * 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.ccsds.ndm.odm.oem;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.orekit.data.DataContext;
  import org.orekit.errors.OrekitException;
  import org.orekit.errors.OrekitMessages;
  import org.orekit.files.ccsds.definitions.TimeSystem;
  import org.orekit.files.ccsds.ndm.NdmConstituent;
  import org.orekit.files.ccsds.ndm.odm.OdmHeader;
  import org.orekit.files.general.EphemerisFile;
  import org.orekit.utils.IERSConventions;
  import org.orekit.utils.TimeStampedPVCoordinates;
  
  /** This class stores all the information of the OEM File parsed by OEMParser.
   * <p>
   * It contains the header and a list of Ephemerides Blocks each containing
   * metadata, a list of ephemerides data lines and optional covariance matrices
   * (and their metadata).
   * </p>
   * @author sports
   * @author Evan Ward
   * @since 6.1
   */
  public class Oem extends NdmConstituent<OdmHeader, OemSegment>
      implements EphemerisFile<TimeStampedPVCoordinates, OemSegment> {
  
      /** Root element for XML files. */
      public static final String ROOT = "oem";
  
      /** Key for format version. */
      public static final String FORMAT_VERSION_KEY = "CCSDS_OEM_VERS";
  
      /** Gravitational coefficient to use for building Cartesian/Keplerian orbits. */
      private final double mu;
  
      /** Simple constructor.
       * @param header file header
       * @param segments file segments
       * @param conventions IERS conventions
       * @param dataContext used for creating frames, time scales, etc.
       * @param mu gravitational coefficient
       */
      public Oem(final OdmHeader header, final List<OemSegment> segments,
                 final IERSConventions conventions, final DataContext dataContext,
                 final double mu) {
          super(header, segments, conventions, dataContext);
          this.mu = mu;
      }
  
      /** {@inheritDoc} */
      @Override
      public Map<String, OemSatelliteEphemeris> getSatellites() {
          final Map<String, List<OemSegment>> byId = new HashMap<>();
          for (final OemSegment segment : getSegments()) {
              final String id = segment.getMetadata().getObjectID();
              byId.putIfAbsent(id, new ArrayList<>());
              byId.get(id).add(segment);
          }
          final Map<String, OemSatelliteEphemeris> ret = new HashMap<>();
          for (final Map.Entry<String, List<OemSegment>> entry : byId.entrySet()) {
              ret.put(entry.getKey(), new OemSatelliteEphemeris(entry.getKey(), mu, entry.getValue()));
          }
          return ret;
      }
  
      /** Check that, according to the CCSDS standard, every OEMBlock has the same time system.
       */
      public void checkTimeSystems() {
          TimeSystem referenceTimeSystem = null;
          for (final OemSegment segment : getSegments()) {
              final TimeSystem timeSystem = segment.getMetadata().getTimeSystem();
              if (referenceTimeSystem == null) {
                  referenceTimeSystem = timeSystem;
              } else if (!referenceTimeSystem.equals(timeSystem)) {
                  throw new OrekitException(OrekitMessages.CCSDS_INCONSISTENT_TIME_SYSTEMS,
                                            referenceTimeSystem.name(), timeSystem.name());
              }
          }
     }
 
 }