/* Copyright 2002-2026 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.omm;
  
  import java.util.List;
  
  import org.orekit.data.DataContext;
  import org.orekit.errors.OrekitException;
  import org.orekit.errors.OrekitMessages;
  import org.orekit.files.ccsds.ndm.NdmConstituent;
  import org.orekit.files.ccsds.ndm.odm.KeplerianElements;
  import org.orekit.files.ccsds.ndm.odm.OdmCommonMetadata;
  import org.orekit.files.ccsds.ndm.odm.OdmHeader;
  import org.orekit.files.ccsds.section.Segment;
  import org.orekit.orbits.CartesianOrbit;
  import org.orekit.orbits.KeplerianOrbit;
  import org.orekit.propagation.SpacecraftState;
  import org.orekit.propagation.analytical.tle.TLE;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.time.TimeStamped;
  import org.orekit.utils.IERSConventions;
  
  /**
   * This class gathers the informations present in the Orbital Mean-Elements Message (OMM).
   * @author sports
   * @since 6.1
   */
  public class Omm extends NdmConstituent<OdmHeader, Segment<OmmMetadata, OmmData>> implements TimeStamped {
  
      /** Root element for XML files. */
      public static final String ROOT = "omm";
  
      /** Key for format version. */
      public static final String FORMAT_VERSION_KEY = "CCSDS_OMM_VERS";
  
      /** Default value for missing optional values. */
      private static final double DEFAULT_MISSING_OPTIONAL_VALUE = 0.0;
  
      /** 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 to use for building Cartesian/Keplerian orbits
       */
      public Omm(final OdmHeader header, final List<Segment<OmmMetadata, OmmData>> segments,
                 final IERSConventions conventions, final DataContext dataContext,
                 final double mu) {
          super(header, segments, conventions, dataContext);
          this.mu = mu;
      }
  
      /** Get the file metadata.
       * @return file metadata
       */
      public OmmMetadata getMetadata() {
          return getSegments().getFirst().getMetadata();
      }
  
      /** Get the file data.
       * @return file data
       */
      public OmmData getData() {
          return getSegments().getFirst().getData();
      }
  
      /** {@inheritDoc} */
      @Override
      public AbsoluteDate getDate() {
          return getData().getKeplerianElementsBlock().getEpoch();
      }
  
      /** Generate a keplerian orbit.
       * @return generated orbit
       */
      public KeplerianOrbit generateKeplerianOrbit() {
          return getData().getKeplerianElementsBlock().generateKeplerianOrbit(getMetadata().getFrame(), mu);
      }
  
      /** Generate spacecraft state from the {@link CartesianOrbit} generated by generateCartesianOrbit.
       *  Raises an exception if OPM doesn't contain spacecraft mass information.
      * @return the spacecraft state of the OPM
      */
     public SpacecraftState generateSpacecraftState() {
         return new SpacecraftState(generateKeplerianOrbit()).withMass(getData().getMass());
     }
 
     /** Generate TLE from OMM file. Launch Year, Launch Day and Launch Piece are not present in the
      * OMM file, they have to be set manually by the user with the AdditionalData static class.
      * @return the tle
      */
     public TLE generateTLE() {
         final OdmCommonMetadata metadata = getMetadata();
         final KeplerianElements kep = getData().getKeplerianElementsBlock();
         final OmmTle            tle = getData().getTLEBlock().orElseThrow(() -> new OrekitException(OrekitMessages.CCSDS_MISSING_OPTIONAL_VALUE));
         return new TLE(tle.getNoradID(), tle.getClassificationType(),
                        metadata.getLaunchYear(), metadata.getLaunchNumber(), metadata.getLaunchPiece(),
                        tle.getEphemerisType(), tle.getElementSetNumber(), kep.getEpoch(),
                        kep.getMeanMotion().orElse(DEFAULT_MISSING_OPTIONAL_VALUE),
                        tle.getMeanMotionDot().orElse(DEFAULT_MISSING_OPTIONAL_VALUE) / 2,
                        tle.getMeanMotionDotDot().orElse(DEFAULT_MISSING_OPTIONAL_VALUE) / 6,
                        kep.getE(), kep.getI(), kep.getPa(), kep.getRaan(),
                        kep.getAnomaly(), tle.getRevAtEpoch(),
                        tle.getBStar().orElse(DEFAULT_MISSING_OPTIONAL_VALUE), getDataContext().getTimeScales().getUTC());
     }
 
 }