TrajectoryStateHistoryWriter.java

/* 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,
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 * See the License for the specific language governing permissions and
 * limitations under the License.
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package org.orekit.files.ccsds.ndm.odm.ocm;

import java.io.IOException;
import java.util.List;

import org.orekit.files.ccsds.definitions.TimeConverter;
import org.orekit.files.ccsds.section.AbstractWriter;
import org.orekit.files.ccsds.utils.FileFormat;
import org.orekit.files.ccsds.utils.generation.Generator;
import org.orekit.utils.units.Unit;

/** Writer for trajectory state history data.
 * @author Luc Maisonobe
 * @since 11.0
 */
class TrajectoryStateHistoryWriter extends AbstractWriter {

    /** Trajectory state history block. */
    private final TrajectoryStateHistory history;

    /** Converter for dates. */
    private final TimeConverter timeConverter;

    /** Create a writer.
     * @param trajectoryStateHistory trajectory state history to write
     * @param timeConverter converter for dates
     */
    TrajectoryStateHistoryWriter(final TrajectoryStateHistory trajectoryStateHistory,
                                 final TimeConverter timeConverter) {
        super(OcmDataSubStructureKey.traj.name(), OcmDataSubStructureKey.TRAJ.name());
        this.history       = trajectoryStateHistory;
        this.timeConverter = timeConverter;
    }

    /** Get state history.
     * @return state history
     * @since 12.0
     */
    TrajectoryStateHistory getHistory() {
        return history;
    }

    /** {@inheritDoc} */
    @Override
    protected void writeContent(final Generator generator) throws IOException {

        // metadata
        writeMetadata(generator);

        // data
        final List<Unit> units = history.getMetadata().getTrajType().getUnits();
        for (final TrajectoryState state : history.getTrajectoryStates()) {
            writeState(generator, state, units);
        }

    }

    /** Write trajectory state history metadata.
     * @param generator generator to use for producing output
     * @throws IOException if any buffer writing operations fails
     * @since 12.0
     */
    protected void writeMetadata(final Generator generator) throws IOException {

        final TrajectoryStateHistoryMetadata metadata = history.getMetadata();
        generator.writeComments(metadata.getComments());

        // identifiers
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.TRAJ_ID.name(),       metadata.getTrajID(),      null, false);
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.TRAJ_PREV_ID.name(),  metadata.getTrajPrevID(),  null, false);
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.TRAJ_NEXT_ID.name(),  metadata.getTrajNextID(),  null, false);
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.TRAJ_BASIS.name(),    metadata.getTrajBasis(),   null, false);
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.TRAJ_BASIS_ID.name(), metadata.getTrajBasisID(), null, false);

        // interpolation
        if (metadata.getInterpolationMethod() != TrajectoryStateHistoryMetadata.DEFAULT_INTERPOLATION_METHOD ||
            metadata.getInterpolationDegree() != TrajectoryStateHistoryMetadata.DEFAULT_INTERPOLATION_DEGREE) {
            generator.writeEntry(TrajectoryStateHistoryMetadataKey.INTERPOLATION.name(),        metadata.getInterpolationMethod(), false);
            generator.writeEntry(TrajectoryStateHistoryMetadataKey.INTERPOLATION_DEGREE.name(), metadata.getInterpolationDegree(), false);
        }

        // propagation
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.PROPAGATOR.name(),       metadata.getPropagator(), null, false);

        // references
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.CENTER_NAME.name(),      metadata.getCenter().getName(),              null, false);
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.TRAJ_REF_FRAME.name(),   metadata.getTrajReferenceFrame().getName(),  null, false);
        if (!metadata.getTrajFrameEpoch().equals(timeConverter.getReferenceDate())) {
            generator.writeEntry(TrajectoryStateHistoryMetadataKey.TRAJ_FRAME_EPOCH.name(), timeConverter, metadata.getTrajFrameEpoch(), true, false);
        }

        // time
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.USEABLE_START_TIME.name(), timeConverter, metadata.getUseableStartTime(), false, false);
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.USEABLE_STOP_TIME.name(),  timeConverter, metadata.getUseableStopTime(),  false, false);

        // revolution  numbers
        if (metadata.getOrbRevNum() > 0) {
            generator.writeEntry(TrajectoryStateHistoryMetadataKey.ORB_REVNUM.name(),       metadata.getOrbRevNum(),      false);
            generator.writeEntry(TrajectoryStateHistoryMetadataKey.ORB_REVNUM_BASIS.name(), metadata.getOrbRevNumBasis(), false);
        }

        // elements
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.TRAJ_TYPE.name(),        metadata.getTrajType(),     true);
        if (metadata.getTrajType() != OrbitElementsType.CARTP   &&
            metadata.getTrajType() != OrbitElementsType.CARTPV  &&
            metadata.getTrajType() != OrbitElementsType.CARTPVA) {
            generator.writeEntry(TrajectoryStateHistoryMetadataKey.ORB_AVERAGING.name(), metadata.getOrbAveraging(), null,  true);
        }
        generator.writeEntry(TrajectoryStateHistoryMetadataKey.TRAJ_UNITS.name(), generator.unitsListToString(metadata.getTrajUnits()), null, false);
    }

    /** Write one trajectory state.
     * @param generator generator to use for producing output
     * @param state state to write
     * @param units elements units
     * @throws IOException if any buffer writing operations fails
     * @since 12.0
     */
    protected void writeState(final Generator generator, final TrajectoryState state, final List<Unit> units)
        throws IOException {

        final double[]      elements = state.getElements();
        final StringBuilder line     = new StringBuilder();
        line.append(generator.dateToString(timeConverter, state.getDate()));
        for (int i = 0; i < units.size(); ++i) {
            line.append(' ');
            line.append(generator.doubleToString(units.get(i).fromSI(elements[i])));
        }
        if (generator.getFormat() == FileFormat.XML) {
            generator.writeEntry(Ocm.TRAJ_LINE, line.toString(), null, true);
        } else {
            generator.writeRawData(line);
            generator.newLine();
        }

    }

}