/* Copyright 2002-2021 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.aem;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.regex.Pattern;
  
  import org.orekit.data.DataContext;
  import org.orekit.data.DataSource;
  import org.orekit.errors.OrekitException;
  import org.orekit.errors.OrekitMessages;
  import org.orekit.files.ccsds.ndm.ParsedUnitsBehavior;
  import org.orekit.files.ccsds.ndm.adm.AdmMetadataKey;
  import org.orekit.files.ccsds.ndm.adm.AdmParser;
  import org.orekit.files.ccsds.section.Header;
  import org.orekit.files.ccsds.section.HeaderProcessingState;
  import org.orekit.files.ccsds.section.KvnStructureProcessingState;
  import org.orekit.files.ccsds.section.MetadataKey;
  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.ProcessingState;
  import org.orekit.files.general.AttitudeEphemerisFileParser;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.utils.IERSConventions;
  
  /**
   * A parser for the CCSDS AEM (Attitude Ephemeris Message).
   * <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>
   * @author Bryan Cazabonne
   * @since 10.2
   */
  public class AemParser extends AdmParser<Aem, AemParser> implements AttitudeEphemerisFileParser<Aem> {
  
      /** Pattern for splitting strings at blanks. */
      private static final Pattern SPLIT_AT_BLANKS = Pattern.compile("\\s+");
  
      /** File header. */
      private Header header;
  
      /** File segments. */
      private List<AemSegment> segments;
  
      /** Metadata for current observation block. */
      private AemMetadata metadata;
  
      /** Context binding valid for current metadata. */
      private ContextBinding context;
  
      /** Current Ephemerides block being parsed. */
      private AemData currentBlock;
  
      /** Default interpolation degree. */
      private int defaultInterpolationDegree;
  
      /** Processor for global message structure. */
      private ProcessingState structureProcessor;
  
      /** Current attitude entry. */
      private AttitudeEntry currentEntry;
  
      /**Complete constructor.
       * <p>
       * Calling this constructor directly is not recommended. Users should rather use
       * {@link org.orekit.files.ccsds.ndm.ParserBuilder#buildAemParser()
       * parserBuilder.buildAemParser()}.
       * </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 defaultInterpolationDegree default interpolation degree
       * @param parsedUnitsBehavior behavior to adopt for handling parsed units
      */
     public AemParser(final IERSConventions conventions, final boolean simpleEOP,
                      final DataContext dataContext, final AbsoluteDate missionReferenceDate,
                      final int defaultInterpolationDegree, final ParsedUnitsBehavior parsedUnitsBehavior) {
         super(Aem.ROOT, Aem.FORMAT_VERSION_KEY, conventions, simpleEOP, dataContext,
               missionReferenceDate, parsedUnitsBehavior);
         this.defaultInterpolationDegree  = defaultInterpolationDegree;
     }
 
     /** {@inheritDoc} */
     @Override
     public Aem parse(final DataSource source) {
         return parseMessage(source);
     }
 
     /** {@inheritDoc} */
     @Override
     public Header getHeader() {
         return header;
     }
 
     /** {@inheritDoc} */
     @Override
     public void reset(final FileFormat fileFormat) {
         header   = new Header(2.0);
         segments = new ArrayList<>();
         metadata = null;
         context  = null;
         if (fileFormat == FileFormat.XML) {
             structureProcessor = new XmlStructureProcessingState(Aem.ROOT, this);
             reset(fileFormat, structureProcessor);
         } else {
             structureProcessor = new KvnStructureProcessingState(this);
             reset(fileFormat, new HeaderProcessingState(this));
         }
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean prepareHeader() {
         anticipateNext(new HeaderProcessingState(this));
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean inHeader() {
         anticipateNext(structureProcessor);
         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 AemMetadata(defaultInterpolationDegree);
         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::processKvnDataToken);
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean finalizeMetadata() {
         metadata.validate(header.getFormatVersion());
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean prepareData() {
         currentBlock = new AemData();
         anticipateNext(getFileFormat() == FileFormat.XML ? this::processXmlSubStructureToken : this::processMetadataToken);
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean inData() {
         anticipateNext(structureProcessor);
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean finalizeData() {
         if (metadata != null) {
             currentBlock.validate(header.getFormatVersion());
             segments.add(new AemSegment(metadata, currentBlock));
         }
         metadata = null;
         context  = null;
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public Aem build() {
         final Aem file = new Aem(header, segments, getConventions(), getDataContext());
         file.checkTimeSystems();
         return file;
     }
 
     /** Manage attitude state section in a XML message.
      * @param starting if true, parser is entering the section
      * otherwise it is leaving the section
      * @return always return true
      */
     boolean manageXmlAttitudeStateSection(final boolean starting) {
         if (starting) {
             currentEntry = new AttitudeEntry(metadata);
             anticipateNext(this::processXmlDataToken);
         } else {
             currentBlock.addData(currentEntry.getCoordinates());
             currentEntry = null;
             anticipateNext(structureProcessor);
         }
         return true;
     }
 
     /** Add a comment to the data section.
      * @param comment comment to add
      * @return always return true
      */
     boolean addDataComment(final String comment) {
         currentBlock.addComment(comment);
         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) {
         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 AemMetadataKey.valueOf(token.getName()).process(token, context, metadata);
                 } catch (IllegalArgumentException iaeE) {
                     // token has not been recognized
                     return false;
                 }
             }
         }
     }
 
     /** Process one XML data substructure token.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processXmlSubStructureToken(final ParseToken token) {
         try {
             return token.getName() != null &&
                    XmlSubStructureKey.valueOf(token.getName()).process(token, this);
         } catch (IllegalArgumentException iae) {
             // token has not been recognized
             return false;
         }
     }
 
     /** Process one data token in a KVN message.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processKvnDataToken(final ParseToken token) {
         inData();
         if ("COMMENT".equals(token.getName())) {
             return token.getType() == TokenType.ENTRY ? currentBlock.addComment(token.getContentAsNormalizedString()) : true;
         } else if (token.getType() == TokenType.RAW_LINE) {
             try {
                 if (metadata.getAttitudeType() == null) {
                     throw new OrekitException(OrekitMessages.CCSDS_MISSING_KEYWORD,
                                               AemMetadataKey.ATTITUDE_TYPE.name(), token.getFileName());
                 }
                 return currentBlock.addData(metadata.getAttitudeType().parse(metadata.isFirst(),
                                                                              metadata.getEndpoints().isExternal2SpacecraftBody(),
                                                                              metadata.getEulerRotSeq(),
                                                                              metadata.isSpacecraftBodyRate(),
                                                                              context, SPLIT_AT_BLANKS.split(token.getRawContent().trim())));
             } catch (NumberFormatException nfe) {
                 throw new OrekitException(nfe, OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
                                           token.getLineNumber(), token.getFileName(), token.getRawContent());
             }
         } else {
             // not a raw line, it is most probably the end of the data section
             return false;
         }
     }
 
     /** Process one data token in a XML message.
      * @param token token to process
      * @return true if token was processed, false otherwise
      */
     private boolean processXmlDataToken(final ParseToken token) {
         anticipateNext(this::processXmlSubStructureToken);
         try {
             return token.getName() != null &&
                    AttitudeEntryKey.valueOf(token.getName()).process(token, context, currentEntry);
         } catch (IllegalArgumentException iae) {
             // token has not been recognized
             return false;
         }
     }
 
 }