/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.inspection.ffmpeg;
  
  import static org.opencastproject.inspection.api.MediaInspectionOptions.OPTION_ACCURATE_FRAME_COUNT;
  import static org.opencastproject.util.data.Collections.map;
  
  import org.opencastproject.inspection.api.MediaInspectionException;
  import org.opencastproject.inspection.ffmpeg.api.AudioStreamMetadata;
  import org.opencastproject.inspection.ffmpeg.api.MediaAnalyzer;
  import org.opencastproject.inspection.ffmpeg.api.MediaAnalyzerException;
  import org.opencastproject.inspection.ffmpeg.api.MediaContainerMetadata;
  import org.opencastproject.inspection.ffmpeg.api.SubtitleStreamMetadata;
  import org.opencastproject.inspection.ffmpeg.api.VideoStreamMetadata;
  import org.opencastproject.mediapackage.AdaptivePlaylist;
  import org.opencastproject.mediapackage.MediaPackageElement;
  import org.opencastproject.mediapackage.MediaPackageElementBuilder;
  import org.opencastproject.mediapackage.MediaPackageElementBuilderFactory;
  import org.opencastproject.mediapackage.MediaPackageElementFlavor;
  import org.opencastproject.mediapackage.Stream;
  import org.opencastproject.mediapackage.Track;
  import org.opencastproject.mediapackage.UnsupportedElementException;
  import org.opencastproject.mediapackage.track.AudioStreamImpl;
  import org.opencastproject.mediapackage.track.SubtitleStreamImpl;
  import org.opencastproject.mediapackage.track.TrackImpl;
  import org.opencastproject.mediapackage.track.VideoStreamImpl;
  import org.opencastproject.util.Checksum;
  import org.opencastproject.util.ChecksumType;
  import org.opencastproject.util.MimeType;
  import org.opencastproject.util.MimeTypes;
  import org.opencastproject.util.NotFoundException;
  import org.opencastproject.util.UnknownFileTypeException;
  import org.opencastproject.util.data.Tuple;
  import org.opencastproject.workspace.api.Workspace;
  
  import org.apache.commons.io.FilenameUtils;
  import org.apache.commons.lang3.BooleanUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.File;
  import java.io.IOException;
  import java.net.URI;
  import java.util.Dictionary;
  import java.util.Hashtable;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  
  /**
   * Contains the business logic for media inspection. Its primary purpose is to decouple the inspection logic from all
   * OSGi/MH job management boilerplate.
   */
  public class MediaInspector {
  
    private static final Logger logger = LoggerFactory.getLogger(MediaInspector.class);
  
    private final Workspace workspace;
    private final String ffprobePath;
  
    public MediaInspector(Workspace workspace, String ffprobePath) {
      this.workspace = workspace;
      this.ffprobePath = ffprobePath;
    }
  
    /**
     * Inspects the element that is passed in as uri.
     *
     * @param trackURI
     *          the element uri
     * @return the inspected track
     * @throws org.opencastproject.inspection.api.MediaInspectionException
     *           if inspection fails
     */
    public Track inspectTrack(URI trackURI, Map<String, String> options) throws MediaInspectionException {
      logger.debug("inspect(" + trackURI + ") called, using workspace " + workspace);
      throwExceptionIfInvalid(options);
  
      try {
        // Get the file from the URL (runtime exception if invalid)
       File file = null;
       try {
         file = workspace.get(trackURI);
       } catch (NotFoundException notFound) {
         throw new MediaInspectionException("Unable to find resource " + trackURI, notFound);
       } catch (IOException ioe) {
         throw new MediaInspectionException("Error reading " + trackURI + " from workspace", ioe);
       }
 
       // Make sure the file has an extension. Otherwise, tools like ffmpeg will not work.
       // TODO: Try to guess the extension from the container's metadata
       if ("".equals(FilenameUtils.getExtension(file.getName()))) {
         throw new MediaInspectionException("Can not inspect files without a filename extension");
       }
 
       MediaContainerMetadata metadata = getFileMetadata(file, getAccurateFrameCount(options));
       if (metadata == null) {
         throw new MediaInspectionException("Media analyzer returned no metadata from " + file);
       } else {
         MediaPackageElementBuilder elementBuilder = MediaPackageElementBuilderFactory.newInstance().newElementBuilder();
         TrackImpl track;
         MediaPackageElement element;
         try {
           element = elementBuilder.elementFromURI(trackURI, MediaPackageElement.Type.Track, null);
         } catch (UnsupportedElementException e) {
           throw new MediaInspectionException("Unable to create track element from " + file, e);
         }
         track = (TrackImpl) element;
 
         // Duration
         if (metadata.getDuration() != null && metadata.getDuration() > 0) {
           track.setDuration(metadata.getDuration());
         }
 
         // Checksum
         try {
           track.setChecksum(Checksum.create(ChecksumType.DEFAULT_TYPE, file));
         } catch (IOException e) {
           throw new MediaInspectionException("Unable to read " + file, e);
         }
 
         // Mimetype
         track.setMimeType(metadata.getMimeType());
         track.setMaster(metadata.getAdaptiveMaster());
 
         // Audio metadata
         try {
           addAudioStreamMetadata(track, metadata);
         } catch (Exception e) {
           throw new MediaInspectionException("Unable to extract audio metadata from " + file, e);
         }
 
         // Video metadata
         try {
           addVideoStreamMetadata(track, metadata);
         } catch (Exception e) {
           throw new MediaInspectionException("Unable to extract video metadata from " + file, e);
         }
 
         // Subtitle metadata
         try {
           addSubtitleStreamMetadata(track, metadata);
         } catch (Exception e) {
           throw new MediaInspectionException("Unable to extract subtitle metadata from " + file, e);
         }
 
         // File size
         track.setSize(file.length());
 
         return track;
       }
     } catch (Exception e) {
       logger.warn("Error inspecting " + trackURI, e);
       if (e instanceof MediaInspectionException) {
         throw (MediaInspectionException) e;
       } else {
         throw new MediaInspectionException(e);
       }
     }
   }
 
   /**
    * Enriches the given element's mediapackage.
    *
    * @param element
    *          the element to enrich
    * @param override
    *          <code>true</code> to override existing metadata
    * @return the enriched element
    * @throws MediaInspectionException
    *           if enriching fails
    */
   public MediaPackageElement enrich(MediaPackageElement element, boolean override, final Map<String, String> options)
           throws MediaInspectionException {
     throwExceptionIfInvalid(options);
     if (element instanceof Track) {
       final Track originalTrack = (Track) element;
       return enrichTrack(originalTrack, override, options);
     } else {
       return enrichElement(element, override, options);
     }
   }
 
   /**
    * Enriches the track's metadata and can be executed in an asynchronous way.
    *
    * @param originalTrack
    *          the original track
    * @param override
    *          <code>true</code> to override existing metadata
    * @return the media package element
    * @throws MediaInspectionException
    */
   private MediaPackageElement enrichTrack(final Track originalTrack, final boolean override,
       final Map<String, String> options) throws MediaInspectionException {
     try {
       URI originalTrackUrl = originalTrack.getURI();
       MediaPackageElementFlavor flavor = originalTrack.getFlavor();
       logger.debug("enrich(" + originalTrackUrl + ") called");
 
       // Get the file from the URL
       File file = null;
       try {
         file = workspace.get(originalTrackUrl);
       } catch (NotFoundException e) {
         throw new MediaInspectionException("File " + originalTrackUrl + " was not found and can therefore not be "
             + "inspected", e);
       } catch (IOException e) {
         throw new MediaInspectionException("Error accessing " + originalTrackUrl, e);
       }
 
       // Make sure the file has an extension. Otherwise, tools like ffmpeg will not work.
       // TODO: Try to guess the extension from the container's metadata
       if ("".equals(FilenameUtils.getExtension(file.getName()))) {
         throw new MediaInspectionException("Can not inspect files without a filename extension");
       }
 
       MediaContainerMetadata metadata = getFileMetadata(file, getAccurateFrameCount(options));
       if (metadata == null) {
         throw new MediaInspectionException("Unable to acquire media metadata for " + originalTrackUrl);
       } else {
         TrackImpl track = null;
         try {
           track = (TrackImpl) MediaPackageElementBuilderFactory.newInstance().newElementBuilder()
                   .elementFromURI(originalTrackUrl, MediaPackageElement.Type.Track, flavor);
         } catch (UnsupportedElementException e) {
           throw new MediaInspectionException("Unable to create track element from " + file, e);
         }
 
         // init the new track with old
         track.setChecksum(originalTrack.getChecksum());
         track.setDuration(originalTrack.getDuration());
         track.setElementDescription(originalTrack.getElementDescription());
         track.setFlavor(flavor);
         track.setIdentifier(originalTrack.getIdentifier());
         // If HLS
         if (!originalTrack.hasMaster() || override) {
           track.setMaster(metadata.getAdaptiveMaster());
         } else {
           track.setMaster(originalTrack.isMaster());
         }
         track.setMimeType(originalTrack.getMimeType());
         track.setReference(originalTrack.getReference());
         track.setSize(file.length());
         track.setURI(originalTrackUrl);
         for (String tag : originalTrack.getTags()) {
           track.addTag(tag);
         }
 
         // enrich the new track with basic info
         if (track.getDuration() == null || override) {
           track.setDuration(metadata.getDuration());
         }
         if (track.getChecksum() == null || override) {
           try {
             track.setChecksum(Checksum.create(ChecksumType.DEFAULT_TYPE, file));
           } catch (IOException e) {
             throw new MediaInspectionException("Unable to read " + file, e);
           }
         }
 
         // Add the mime type if it's not already present
         if (track.getMimeType() == null || override) {
           track.setMimeType(metadata.getMimeType());
         }
 
         // find all streams
         Dictionary<String, Stream> streamsId2Stream = new Hashtable<String, Stream>();
         for (Stream stream : originalTrack.getStreams()) {
           streamsId2Stream.put(stream.getIdentifier(), stream);
         }
 
         // audio list
         try {
           addAudioStreamMetadata(track, metadata);
         } catch (Exception e) {
           throw new MediaInspectionException("Unable to extract audio metadata from " + file, e);
         }
 
         // video list
         try {
           addVideoStreamMetadata(track, metadata);
         } catch (Exception e) {
           throw new MediaInspectionException("Unable to extract video metadata from " + file, e);
         }
 
         // Subtitle metadata
         try {
           addSubtitleStreamMetadata(track, metadata);
         } catch (Exception e) {
           throw new MediaInspectionException("Unable to extract subtitle metadata from " + file, e);
         }
 
         logger.info("Successfully inspected track {}", track);
         return track;
       }
     } catch (Exception e) {
       logger.warn("Error enriching track " + originalTrack, e);
       if (e instanceof MediaInspectionException) {
         throw (MediaInspectionException) e;
       } else {
         throw new MediaInspectionException(e);
       }
     }
   }
 
   /**
    * Enriches the media package element metadata such as the mime type, the file size etc. The method mutates the
    * argument element.
    *
    * @param element
    *          the media package element
    * @param override
    *          <code>true</code> to overwrite existing metadata
    * @return the enriched element
    * @throws MediaInspectionException
    *           if enriching fails
    */
   private MediaPackageElement enrichElement(final MediaPackageElement element, final boolean override,
           final Map<String, String> options) throws MediaInspectionException {
     try {
       File file;
       try {
         file = workspace.get(element.getURI());
       } catch (NotFoundException e) {
         throw new MediaInspectionException("Unable to find " + element.getURI() + " in the workspace", e);
       } catch (IOException e) {
         throw new MediaInspectionException("Error accessing " + element.getURI() + " in the workspace", e);
       }
 
       // Checksum
       if (element.getChecksum() == null || override) {
         try {
           element.setChecksum(Checksum.create(ChecksumType.DEFAULT_TYPE, file));
         } catch (IOException e) {
           throw new MediaInspectionException("Error generating checksum for " + element.getURI(), e);
         }
       }
 
       // Mimetype
       if (element.getMimeType() == null || override) {
         try {
           element.setMimeType(MimeTypes.fromString(file.getPath()));
         } catch (UnknownFileTypeException e) {
           logger.info("unable to determine the mime type for {}", file.getName());
         }
       }
 
       logger.info("Successfully inspected element {}", element);
 
       return element;
     } catch (Exception e) {
       logger.warn("Error enriching element " + element, e);
       if (e instanceof MediaInspectionException) {
         throw (MediaInspectionException) e;
       } else {
         throw new MediaInspectionException(e);
       }
     }
   }
 
   /**
    * Asks the media analyzer to extract the file's metadata.
    *
    * @param file
    *          the file
    * @return the file container metadata
    * @throws MediaInspectionException
    *           if metadata extraction fails
    */
   private MediaContainerMetadata getFileMetadata(File file, boolean accurateFrameCount)
           throws MediaInspectionException {
     if (file == null) {
       throw new IllegalArgumentException("file to analyze cannot be null");
     }
     try {
       MediaAnalyzer analyzer = new FFmpegAnalyzer(accurateFrameCount);
       analyzer.setConfig(map(Tuple.<String, Object> tuple(FFmpegAnalyzer.FFPROBE_BINARY_CONFIG, ffprobePath)));
 
       MediaContainerMetadata metadata = analyzer.analyze(file);
       // - setting mimetype for all media
       try {
         // Add mimeType - important for some browsers, eg: safari
         MimeType mimeType = MimeTypes.fromString(file.getName());
         // The mimetype library doesn't know about stream metadata, so the type might be wrong.
         // TODO: these mime types might be incorrect
         // application/ is a special case for HLS manifest files
         if (metadata.hasVideoStreamMetadata()) {
           if (!"video".equals(mimeType.getType()) && !"application".equals(mimeType.getType())) {
             mimeType = MimeTypes.parseMimeType("video/" + mimeType.getSubtype());
           }
         } else if (metadata.hasAudioStreamMetadata()) {
           if (!"audio".equals(mimeType.getType()) && !"application".equals(mimeType.getType())) {
             mimeType = MimeTypes.parseMimeType("audio/" + mimeType.getSubtype());
           }
         } else if (metadata.hasSubtitleStreamMetadata()) {
           if (!"text".equals(mimeType.getType()) && !"application".equals(mimeType.getType())) {
             mimeType = MimeTypes.parseMimeType("text/" + mimeType.getSubtype());
           }
         }
         metadata.setMimeType(mimeType);
       } catch (UnknownFileTypeException e) {
         logger.error("parsing mimeType failed for {} : {}", file, e.getMessage());
         throw new MediaAnalyzerException("parsing mimetype failed for file" + file);
       }
       // - setting adaptive play list master
       // ffmpeg will show format_name == hls
       // but does not distinguish variant playlist from master
       try { // parse text only for correct file extensions
         metadata.setAdaptiveMaster(AdaptivePlaylist.checkForMaster(file));
       } catch (IOException e) {
         logger.error("parsing adaptive playlist failed for {} : {}", file, e.getMessage());
         throw new MediaAnalyzerException("parsing for adaptive playlist master failed for file" + file);
       }
       return metadata;
     } catch (MediaAnalyzerException e) {
       throw new MediaInspectionException(e);
     }
   }
 
   /**
    * Adds the video related metadata to the track.
    *
    * @param track
    *          the track
    * @param metadata
    *          the container metadata
    * @throws Exception
    *           Media analysis is fragile, and may throw any kind of runtime exceptions due to inconsistencies in the
    *           media's metadata
    */
   private Track addVideoStreamMetadata(TrackImpl track, MediaContainerMetadata metadata) throws Exception {
     List<VideoStreamMetadata> videoList = metadata.getVideoStreamMetadata();
     if (videoList != null && !videoList.isEmpty()) {
       for (int i = 0; i < videoList.size(); i++) {
         VideoStreamImpl video = new VideoStreamImpl("video-" + (i + 1));
         VideoStreamMetadata v = videoList.get(i);
         video.setBitRate(v.getBitRate());
         video.setFormat(v.getFormat());
         video.setFormatVersion(v.getFormatVersion());
         video.setFrameCount(v.getFrames());
         video.setFrameHeight(v.getFrameHeight());
         video.setFrameRate(v.getFrameRate());
         video.setFrameWidth(v.getFrameWidth());
         video.setScanOrder(v.getScanOrder());
         video.setScanType(v.getScanType());
         // TODO: retain the original video metadata
         track.addStream(video);
       }
     }
     return track;
   }
 
   /**
    * Adds the audio related metadata to the track.
    *
    * @param track
    *          the track
    * @param metadata
    *          the container metadata
    * @throws Exception
    *           Media analysis is fragile, and may throw any kind of runtime exceptions due to inconsistencies in the
    *           media's metadata
    */
   private Track addAudioStreamMetadata(TrackImpl track, MediaContainerMetadata metadata) throws Exception {
     List<AudioStreamMetadata> audioList = metadata.getAudioStreamMetadata();
     if (audioList != null && !audioList.isEmpty()) {
       for (int i = 0; i < audioList.size(); i++) {
         AudioStreamImpl audio = new AudioStreamImpl("audio-" + (i + 1));
         AudioStreamMetadata a = audioList.get(i);
         audio.setBitRate(a.getBitRate());
         audio.setChannels(a.getChannels());
         audio.setFormat(a.getFormat());
         audio.setFormatVersion(a.getFormatVersion());
         audio.setFrameCount(a.getFrames());
         audio.setBitDepth(a.getResolution());
         audio.setSamplingRate(a.getSamplingRate());
         // TODO: retain the original audio metadata
         track.addStream(audio);
       }
     }
     return track;
   }
 
 
   /**
    * Adds the subtitle related metadata to the track.
    *
    * @param track
    *          the track
    * @param metadata
    *          the container metadata
    * @throws Exception
    *           Media analysis is fragile, and may throw any kind of runtime exceptions due to inconsistencies in the
    *           media's metadata
    */
   private Track addSubtitleStreamMetadata(TrackImpl track, MediaContainerMetadata metadata) throws Exception {
     List<SubtitleStreamMetadata> subtitleList = metadata.getSubtitleStreamMetadata();
     if (subtitleList != null && !subtitleList.isEmpty()) {
       for (int i = 0; i < subtitleList.size(); i++) {
         SubtitleStreamImpl subtitle = new SubtitleStreamImpl("subtitle-" + (i + 1));
         SubtitleStreamMetadata s = subtitleList.get(i);
         subtitle.setFormat(s.getFormat());
         subtitle.setFormatVersion(s.getFormatVersion());
         subtitle.setFrameCount(s.getFrames());
         // TODO: retain the original subtitle metadata
         track.addStream(subtitle);
       }
     }
     return track;
   }
 
   /* Return true if OPTION_ACCURATE_FRAME_COUNT is set to true, false otherwise */
   private boolean getAccurateFrameCount(final Map<String, String> options) {
     return BooleanUtils.toBoolean(options.get(OPTION_ACCURATE_FRAME_COUNT));
   }
 
   /* Throws an exception if an unsupported option is set */
   private void throwExceptionIfInvalid(final Map<String, String> options) throws MediaInspectionException {
     if (options != null) {
       for (Entry e : options.entrySet()) {
         if (e.getKey().equals(OPTION_ACCURATE_FRAME_COUNT)) {
           // This option is supported
         } else {
           throw new MediaInspectionException("Unsupported option " + e.getKey());
         }
       }
     } else {
       throw new MediaInspectionException("Options must not be null");
     }
   }
 }