/* 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.adm.apm;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.function.Function;
  
  import org.orekit.data.DataContext;
  import org.orekit.files.ccsds.definitions.CcsdsFrameMapper;
  import org.orekit.files.ccsds.ndm.ParsedUnitsBehavior;
  import org.orekit.files.ccsds.ndm.adm.AdmCommonMetadataKey;
  import org.orekit.files.ccsds.ndm.adm.AdmHeader;
  import org.orekit.files.ccsds.ndm.adm.AdmMetadata;
  import org.orekit.files.ccsds.ndm.adm.AdmMetadataKey;
  import org.orekit.files.ccsds.ndm.adm.AdmParser;
  import org.orekit.files.ccsds.section.CommentsContainer;
  import org.orekit.files.ccsds.section.HeaderProcessingState;
  import org.orekit.files.ccsds.section.MetadataKey;
  import org.orekit.files.ccsds.section.Segment;
  import org.orekit.files.ccsds.section.XmlStructureProcessingState;
  import org.orekit.files.ccsds.utils.ContextBinding;
  import org.orekit.files.ccsds.utils.FileFormat;
  import org.orekit.files.ccsds.utils.lexical.ParseToken;
  import org.orekit.files.ccsds.utils.lexical.TokenType;
  import org.orekit.files.ccsds.utils.parsing.ErrorState;
  import org.orekit.files.ccsds.utils.parsing.ProcessingState;
  import org.orekit.frames.Frame;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.utils.IERSConventions;
  
  /**
   * A parser for the CCSDS APM (Attitude Parameter Message).
   * @author Bryan Cazabonne * <p>
   * Note than starting with Orekit 11.0, CCSDS message parsers are
   * mutable objects that gather the data being parsed, until the
   * message is complete and the {@link #parseMessage(org.orekit.data.DataSource)
   * parseMessage} method has returned. This implies that parsers
   * should <em>not</em> be used in a multi-thread context. The recommended
   * way to use parsers is to either dedicate one parser for each message
   * and drop it afterwards, or to use a single-thread loop.
   * </p>
  
   * @since 10.2
   */
  public class ApmParser extends AdmParser<Apm, ApmParser> {
  
      /** File header. */
      private AdmHeader header;
  
      /** File segments. */
      private List<Segment<AdmMetadata, ApmData>> segments;
  
      /** APM metadata being read. */
      private AdmMetadata metadata;
  
      /** Context binding valid for current metadata. */
      private ContextBinding context;
  
      /** APM epoch.
       * @since 12.0
       */
      private AbsoluteDate epoch;
  
      /** APM general comments block being read. */
      private CommentsContainer commentsBlock;
  
      /** APM quaternion logical block being read. */
      private ApmQuaternion quaternionBlock;
  
      /** APM Euler angles logical block being read. */
      private Euler eulerBlock;
  
      /** APM angular velocity logical block being read.
       * @since 12.0
       */
      private AngularVelocity angularVelocityBlock;
  
      /** APM spin-stabilized logical block being read. */
      private SpinStabilized spinStabilizedBlock;
  
      /** APM inertia block being read.
       * @since 12.0
       */
      private Inertia inertiaBlock;
 
     /** Current maneuver. */
     private Maneuver currentManeuver;
 
     /** All maneuvers. */
     private List<Maneuver> maneuvers;
 
     /** Processor for global message structure. */
     private ProcessingState structureProcessor;
 
     /** Complete constructor.
      * <p>
      * Calling this constructor directly is not recommended. Users should rather use
      * {@link org.orekit.files.ccsds.ndm.ParserBuilder#buildApmParser()
      * parserBuilder.buildApmParser()}.
      * </p>
      * @param conventions IERS Conventions
      * @param simpleEOP if true, tidal effects are ignored when interpolating EOP
      * @param dataContext used to retrieve frames, time scales, etc.
      * @param missionReferenceDate reference date for Mission Elapsed Time or Mission Relative Time time systems
      * (may be null if time system is absolute)
      * @param parsedUnitsBehavior behavior to adopt for handling parsed units
      * @param filters filters to apply to parse tokens
      * @param frameMapper for creating an Orekit {@link Frame}.
      * @since 13.1.5
      */
     public ApmParser(final IERSConventions conventions, final boolean simpleEOP, final DataContext dataContext,
                      final AbsoluteDate missionReferenceDate, final ParsedUnitsBehavior parsedUnitsBehavior,
                      final Function<ParseToken, List<ParseToken>>[] filters,
                      final CcsdsFrameMapper frameMapper) {
         super(Apm.ROOT, Apm.FORMAT_VERSION_KEY, conventions, simpleEOP, dataContext,
               missionReferenceDate, parsedUnitsBehavior, filters, frameMapper);
     }
 
     /** {@inheritDoc} */
     @Override
     public AdmHeader getHeader() {
         return header;
     }
 
     /** {@inheritDoc} */
     @Override
     public void reset(final FileFormat fileFormat) {
         header              = new AdmHeader();
         segments            = new ArrayList<>();
         metadata            = null;
         context             = null;
         quaternionBlock     = null;
         eulerBlock          = null;
         spinStabilizedBlock = null;
         inertiaBlock        = null;
         currentManeuver     = null;
         maneuvers           = new ArrayList<>();
         if (fileFormat == FileFormat.XML) {
             structureProcessor = new XmlStructureProcessingState(Apm.ROOT, this);
             reset(fileFormat, structureProcessor);
         } else {
             structureProcessor = new ErrorState(); // should never be called
             reset(fileFormat, new HeaderProcessingState(this));
         }
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean prepareHeader() {
         anticipateNext(new HeaderProcessingState(this));
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean inHeader() {
         anticipateNext(getFileFormat() == FileFormat.XML ? structureProcessor : this::processMetadataToken);
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean finalizeHeader() {
         header.validate(header.getFormatVersion());
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean prepareMetadata() {
         if (metadata != null) {
             return false;
         }
         metadata  = new AdmMetadata(getFrameMapper());
         context   = new ContextBinding(this::getConventions, this::isSimpleEOP,
                                        this::getDataContext, this::getParsedUnitsBehavior,
                                        this::getMissionReferenceDate,
                                        metadata::getTimeSystem, () -> 0.0, () -> 1.0);
         anticipateNext(this::processMetadataToken);
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean inMetadata() {
         anticipateNext(getFileFormat() == FileFormat.XML ? structureProcessor : this::processDataToken);
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean finalizeMetadata() {
         metadata.validate(header.getFormatVersion());
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean prepareData() {
         commentsBlock = new CommentsContainer();
         anticipateNext(getFileFormat() == FileFormat.KVN && header.getFormatVersion() < 2.0 ?
                        this::processDataToken : this::processDataSubStructureToken);
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean inData() {
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean finalizeData() {
         if (metadata != null) {
             final ApmData data = new ApmData(commentsBlock, epoch, quaternionBlock, eulerBlock,
                                              angularVelocityBlock, spinStabilizedBlock, inertiaBlock);
             if (currentManeuver != null) {
                 // current maneuver is completed
                 maneuvers.add(currentManeuver);
                 currentManeuver = null;
             }
             for (final Maneuver maneuver : maneuvers) {
                 data.addManeuver(maneuver);
             }
             data.validate(header.getFormatVersion());
             segments.add(new Segment<>(metadata, data));
         }
         metadata             = null;
         context              = null;
         quaternionBlock      = null;
         eulerBlock           = null;
         angularVelocityBlock = null;
         spinStabilizedBlock  = null;
         inertiaBlock         = null;
         currentManeuver      = null;
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public Apm build() {
         // APM KVN file lack a DATA_STOP keyword, hence we can't call finalizeData()
         // automatically before the end of the file
         finalizeData();
         final Apm file = new Apm(header, segments, getConventions(), getDataContext());
         return file;
     }
 
     /** Add a general comment.
      * @param comment comment to add
      * @return always return true
      */
     boolean addGeneralComment(final String comment) {
         return commentsBlock.addComment(comment);
     }
 
     /** Set current epoch.
      * @param epoch epoch to set
      * @since 12.0
      */
     void setEpoch(final AbsoluteDate epoch) {
         this.epoch = epoch;
     }
 
     /** Manage quaternion section.
      * @param starting if true, parser is entering the section
      * otherwise it is leaving the section
      * @return always return true
      */
     boolean manageQuaternionSection(final boolean starting) {
         anticipateNext(starting ? this::processQuaternionToken : structureProcessor);
         return true;
     }
 
     /** Manage Euler elements / three axis stabilized section.
      * @param starting if true, parser is entering the section
      * otherwise it is leaving the section
      * @return always return true
      */
     boolean manageEulerElementsSection(final boolean starting) {
         anticipateNext(starting ? this::processEulerToken : structureProcessor);
         return true;
     }
 
     /** Manage angular velocity section.
      * @param starting if true, parser is entering the section
      * otherwise it is leaving the section
      * @return always return true
      * @since 12.0
      */
     boolean manageAngularVelocitylementsSection(final boolean starting) {
         anticipateNext(starting ? this::processAngularVelocityToken : structureProcessor);
         return true;
     }
 
     /** Manage Euler elements /spin stabilized section.
      * @param starting if true, parser is entering the section
      * otherwise it is leaving the section
      * @return always return true
      */
     boolean manageSpinElementsSection(final boolean starting) {
         anticipateNext(starting ? this::processSpinStabilizedToken : structureProcessor);
         return true;
     }
 
     /** Manage inertia section.
      * @param starting if true, parser is entering the section
      * otherwise it is leaving the section
      * @return always return true
      * @since 12.0
      */
     boolean manageInertiaSection(final boolean starting) {
         anticipateNext(starting ? this::processInertiaToken : structureProcessor);
         return true;
     }
 
     /** Manage maneuver parameters section.
      * @param starting if true, parser is entering the section
      * otherwise it is leaving the section
      * @return always return true
      */
     boolean manageManeuverParametersSection(final boolean starting) {
         anticipateNext(starting ? this::processManeuverToken : structureProcessor);
         return true;
     }
 
     /** Process one metadata token.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processMetadataToken(final ParseToken token) {
         if (metadata == null) {
             // APM KVN file lack a META_START keyword, hence we can't call prepareMetadata()
             // automatically before the first metadata token arrives
             prepareMetadata();
         }
         inMetadata();
         try {
             return token.getName() != null &&
                    MetadataKey.valueOf(token.getName()).process(token, context, metadata);
         } catch (IllegalArgumentException iaeM) {
             try {
                 return AdmMetadataKey.valueOf(token.getName()).process(token, context, metadata);
             } catch (IllegalArgumentException iaeD) {
                 try {
                     return AdmCommonMetadataKey.valueOf(token.getName()).process(token, context, metadata);
                 } catch (IllegalArgumentException iaeC) {
                     // token has not been recognized
                     return false;
                 }
             }
         }
     }
 
     /** Process one data substructure token.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processDataSubStructureToken(final ParseToken token) {
         try {
             return token.getName() != null &&
                    ApmDataSubStructureKey.valueOf(token.getName()).process(token, context, this);
         } catch (IllegalArgumentException iae) {
             // token has not been recognized
             return false;
         }
     }
 
     /** Process one data token.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processDataToken(final ParseToken token) {
         if (commentsBlock == null) {
             // APM KVN file lack a META_STOP keyword, hence we can't call finalizeMetadata()
             // automatically before the first data token arrives
             finalizeMetadata();
             // APM KVN file lack a DATA_START keyword, hence we can't call prepareData()
             // automatically before the first data token arrives
             prepareData();
         }
         anticipateNext(getFileFormat() == FileFormat.KVN && header.getFormatVersion() < 2.0 ?
                        this::processQuaternionToken : this::processDataSubStructureToken);
         if ("COMMENT".equals(token.getName())) {
             if (token.getType() == TokenType.ENTRY) {
                 commentsBlock.addComment(token.getContentAsNormalizedString());
             }
             return true;
         } else if ("EPOCH".equals(token.getName())) {
             if (token.getType() == TokenType.ENTRY) {
                 token.processAsDate(date -> epoch = date, context);
             }
             return true;
         } else {
             return false;
         }
     }
 
     /** Process one quaternion data token.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processQuaternionToken(final ParseToken token) {
         commentsBlock.refuseFurtherComments();
         if (quaternionBlock == null) {
             quaternionBlock = new ApmQuaternion(getFrameMapper());
         }
         anticipateNext(getFileFormat() == FileFormat.KVN && header.getFormatVersion() < 2.0 ?
                        this::processEulerToken : this::processDataSubStructureToken);
         try {
             return token.getName() != null &&
                    ApmQuaternionKey.valueOf(token.getName()).process(token, context, quaternionBlock, this::setEpoch);
         } catch (IllegalArgumentException iae) {
             // token has not been recognized
             return false;
         }
     }
 
     /** Process one Euler angles data token.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processEulerToken(final ParseToken token) {
         commentsBlock.refuseFurtherComments();
         if (eulerBlock == null) {
             eulerBlock = new Euler(getFrameMapper());
             if (moveCommentsIfEmpty(quaternionBlock, eulerBlock)) {
                 // get rid of the empty logical block
                 quaternionBlock = null;
             }
         }
         anticipateNext(getFileFormat() == FileFormat.KVN && header.getFormatVersion() < 2.0 ?
                        this::processAngularVelocityToken : this::processDataSubStructureToken);
         try {
             return token.getName() != null &&
                    EulerKey.valueOf(token.getName()).process(token, context, eulerBlock);
         } catch (IllegalArgumentException iae) {
             // token has not been recognized
             return false;
         }
     }
 
     /** Process one angular velocity data token.
      * @param token token to process
      * @return true if token was processed, false otherwise
      * @since 12.0
      */
     private boolean processAngularVelocityToken(final ParseToken token) {
         commentsBlock.refuseFurtherComments();
         if (angularVelocityBlock == null) {
             angularVelocityBlock = new AngularVelocity(getFrameMapper());
             if (moveCommentsIfEmpty(eulerBlock, angularVelocityBlock)) {
                 // get rid of the empty logical block
                 eulerBlock = null;
             }
         }
         anticipateNext(getFileFormat() == FileFormat.KVN && header.getFormatVersion() < 2.0 ?
                        this::processSpinStabilizedToken : this::processDataSubStructureToken);
         try {
             return token.getName() != null &&
                    AngularVelocityKey.valueOf(token.getName()).process(token, context, angularVelocityBlock);
         } catch (IllegalArgumentException iae) {
             // token has not been recognized
             return false;
         }
     }
 
     /** Process one spin-stabilized data token.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processSpinStabilizedToken(final ParseToken token) {
         commentsBlock.refuseFurtherComments();
         if (spinStabilizedBlock == null) {
             spinStabilizedBlock = new SpinStabilized(getFrameMapper());
             if (moveCommentsIfEmpty(angularVelocityBlock, spinStabilizedBlock)) {
                 // get rid of the empty logical block
                 angularVelocityBlock = null;
             }
         }
         anticipateNext(getFileFormat() == FileFormat.KVN && header.getFormatVersion() < 2.0 ?
                        this::processInertiaToken : this::processDataSubStructureToken);
         try {
             return token.getName() != null &&
                    SpinStabilizedKey.valueOf(token.getName()).process(token, context, spinStabilizedBlock);
         } catch (IllegalArgumentException iae) {
             // token has not been recognized
             return false;
         }
     }
 
     /** Process one spacecraft parameters data token.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processInertiaToken(final ParseToken token) {
         commentsBlock.refuseFurtherComments();
         if (inertiaBlock == null) {
             inertiaBlock = new Inertia();
             if (moveCommentsIfEmpty(spinStabilizedBlock, inertiaBlock)) {
                 // get rid of the empty logical block
                 spinStabilizedBlock = null;
             }
         }
         anticipateNext(getFileFormat() == FileFormat.KVN && header.getFormatVersion() < 2.0 ?
                                           this::processManeuverToken : this::processDataSubStructureToken);
         try {
             return token.getName() != null &&
                    InertiaKey.valueOf(token.getName()).process(token, context, inertiaBlock);
         } catch (IllegalArgumentException iae) {
             // token has not been recognized
             return false;
         }
     }
 
     /** Process one maneuver data token.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processManeuverToken(final ParseToken token) {
         commentsBlock.refuseFurtherComments();
         if (currentManeuver == null) {
             currentManeuver = new Maneuver();
             if (moveCommentsIfEmpty(inertiaBlock, currentManeuver)) {
                 // get rid of the empty logical block
                 inertiaBlock = null;
             }
         }
         anticipateNext(getFileFormat() == FileFormat.KVN && header.getFormatVersion() < 2.0 ?
                        new ErrorState() : this::processDataSubStructureToken);
         try {
             return token.getName() != null &&
                    ManeuverKey.valueOf(token.getName()).process(token, context, currentManeuver);
         } catch (IllegalArgumentException iae) {
             // token has not been recognized
             maneuvers.add(currentManeuver);
             currentManeuver = null;
             return false;
         }
     }
 
     /** Move comments from one empty logical block to another logical block.
      * @param origin origin block
      * @param destination destination block
      * @return true if origin block was empty
      */
     private boolean moveCommentsIfEmpty(final CommentsContainer origin, final CommentsContainer destination) {
         if (origin != null && origin.acceptComments()) {
             // origin block is empty, move the existing comments
             for (final String comment : origin.getComments()) {
                 destination.addComment(comment);
             }
             return true;
         } else {
             return false;
         }
     }
 
 }