/*
    * 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.workflow.handler.composer;
  
  import static java.lang.String.format;
  import static org.opencastproject.util.EqualsUtil.eq;
  
  import org.opencastproject.composer.api.ComposerService;
  import org.opencastproject.composer.api.EncodingProfile;
  import org.opencastproject.job.api.Job;
  import org.opencastproject.job.api.JobBarrier;
  import org.opencastproject.job.api.JobContext;
  import org.opencastproject.mediapackage.Attachment;
  import org.opencastproject.mediapackage.MediaPackage;
  import org.opencastproject.mediapackage.MediaPackageElementFlavor;
  import org.opencastproject.mediapackage.MediaPackageElementParser;
  import org.opencastproject.mediapackage.MediaPackageException;
  import org.opencastproject.mediapackage.MediaPackageSupport;
  import org.opencastproject.mediapackage.Track;
  import org.opencastproject.mediapackage.VideoStream;
  import org.opencastproject.mediapackage.selector.TrackSelector;
  import org.opencastproject.serviceregistry.api.ServiceRegistry;
  import org.opencastproject.util.JobUtil;
  import org.opencastproject.util.MimeTypes;
  import org.opencastproject.util.UnknownFileTypeException;
  import org.opencastproject.util.data.Collections;
  import org.opencastproject.workflow.api.AbstractWorkflowOperationHandler;
  import org.opencastproject.workflow.api.ConfiguredTagsAndFlavors;
  import org.opencastproject.workflow.api.WorkflowInstance;
  import org.opencastproject.workflow.api.WorkflowOperationException;
  import org.opencastproject.workflow.api.WorkflowOperationHandler;
  import org.opencastproject.workflow.api.WorkflowOperationInstance;
  import org.opencastproject.workflow.api.WorkflowOperationResult;
  import org.opencastproject.workflow.api.WorkflowOperationResult.Action;
  import org.opencastproject.workspace.api.Workspace;
  
  import org.apache.commons.io.FilenameUtils;
  import org.osgi.service.component.annotations.Component;
  import org.osgi.service.component.annotations.Reference;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.net.URI;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.IllegalFormatException;
  import java.util.List;
  import java.util.Locale;
  import java.util.Objects;
  import java.util.Optional;
  import java.util.stream.Collectors;
  
  /**
   * The workflow definition for handling "image" operations
   */
  @Component(
      immediate = true,
      service = WorkflowOperationHandler.class,
      property = {
          "service.description=Image Workflow Operation Handler",
          "workflow.operation=image"
      }
  )
  public class ImageWorkflowOperationHandler extends AbstractWorkflowOperationHandler {
    /** The logging facility */
    private static final Logger logger = LoggerFactory.getLogger(ImageWorkflowOperationHandler.class);
  
    // legacy option
    public static final String OPT_PROFILES = "encoding-profile";
    public static final String OPT_POSITIONS = "time";
    public static final String OPT_TARGET_BASE_NAME_FORMAT_SECOND = "target-base-name-format-second";
    public static final String OPT_TARGET_BASE_NAME_FORMAT_PERCENT = "target-base-name-format-percent";
    public static final String OPT_END_MARGIN = "end-margin";
  
    private static final long END_MARGIN_DEFAULT = 100;
    public static final double SINGLE_FRAME_POS = 0.0;
  
    /** The composer service */
    private ComposerService composerService = null;
  
   /** The local workspace */
   private Workspace workspace = null;
 
   /**
    * Callback for the OSGi declarative services configuration.
    *
    * @param composerService
    *          the composer service
    */
   @Reference
   protected void setComposerService(ComposerService composerService) {
     this.composerService = composerService;
   }
 
   /**
    * Callback for declarative services configuration that will introduce us to the local workspace service.
    * Implementation assumes that the reference is configured as being static.
    *
    * @param workspace
    *          an instance of the workspace
    */
   @Reference
   public void setWorkspace(Workspace workspace) {
     this.workspace = workspace;
   }
 
   @Override
   public WorkflowOperationResult start(final WorkflowInstance wi, JobContext ctx)
       throws WorkflowOperationException {
     logger.debug("Running image workflow operation on {}", wi);
     try {
       MediaPackage mp = wi.getMediaPackage();
       final Cfg cfg = configure(mp, wi);
       mp = MediaPackageSupport.copy(mp);
 
       // Extract
       if (cfg.sourceTracks.size() == 0) {
         logger.info("No source tracks found in media package {}, skipping operation", mp.getIdentifier());
         return this.createResult(mp, Action.SKIP);
       }
       // start image extraction jobs
       final List<Extraction> extractions = cfg.sourceTracks.stream().flatMap(track -> {
         final List<MediaPosition> positions = limit(track, cfg.positions);
         if (positions.size() != cfg.positions.size()) {
           logger.warn("Could not apply all configured positions to track {}", track);
         }
         logger.info("Extracting images from {} at position {}", track, positions);
         // create one extraction per encoding profile
         return cfg.profiles.stream()
             .map(profile -> {
               try {
                 return new Extraction(extractImages(this, track, profile, positions, cfg), track, profile, positions);
               } catch (WorkflowOperationException e) {
                 throw new RuntimeException(e);
               }
             });
       }).collect(Collectors.toList());
       final List<Job> extractionJobs = concatJobs(extractions);
       final JobBarrier.Result extractionResult = JobUtil.waitForJobs(this.serviceRegistry, extractionJobs);
       if (extractionResult.isSuccess()) {
         // all extractions were successful; iterate them
         for (final Extraction extraction : extractions) {
           final List<Attachment> images = getImages(extraction.job);
           final int expectedNrOfImages = extraction.positions.size();
           if (images.size() == expectedNrOfImages) {
             // post process images
             int size = Math.min(images.size(), extraction.positions.size());
             for (int i = 0; i < size; i++) {
               Attachment image = images.get(i);
               MediaPosition position = extraction.positions.get(i);
               adjustMetadata(extraction, image, cfg);
               if (image.getIdentifier() == null) {
                 image.generateIdentifier();
               }
               mp.addDerived(image, extraction.track);
               String fileName = createFileName(
                   extraction.profile.getSuffix(), extraction.track.getURI(), position, cfg);
               moveToWorkspace(this, mp, image, fileName);
             }
           } else {
             // fewer images than expected have been extracted
             throw new WorkflowOperationException(
                 format("Only %s of %s images have been extracted from track %s",
                     images.size(), expectedNrOfImages, extraction.track));
           }
         }
         return this.createResult(mp, Action.CONTINUE, JobUtil.sumQueueTime(extractionJobs));
       } else {
         throw new WorkflowOperationException("Image extraction failed");
       }
     } catch (Exception e) {
       throw new WorkflowOperationException(e);
     }
   }
 
   /**
    * Adjust flavor, tags, mime type of <code>image</code> according to the
    * configuration and the extraction.
    */
   protected void adjustMetadata(Extraction extraction, Attachment image, Cfg cfg) {
     // Adjust the target flavor. Make sure to account for partial updates
     for (final MediaPackageElementFlavor flavor : cfg.targetImageFlavor) {
       final String flavorType = eq("*", flavor.getType())
           ? extraction.track.getFlavor().getType()
           : flavor.getType();
       final String flavorSubtype = eq("*", flavor.getSubtype())
           ? extraction.track.getFlavor().getSubtype()
           : flavor.getSubtype();
       image.setFlavor(new MediaPackageElementFlavor(flavorType, flavorSubtype));
       logger.debug("Resulting image has flavor '{}'", image.getFlavor());
     }
     // Set the mime type
     try {
       image.setMimeType(MimeTypes.fromURI(image.getURI()));
     } catch (UnknownFileTypeException e) {
       logger.warn("Mime type unknown for file {}. Setting none.", image.getURI(), e);
     }
     // Add tags
     applyTargetTagsToElement(cfg.targetImageTags, image);
   }
 
   /** Create a file name for the extracted image. */
   protected String createFileName(final String suffix, final URI trackUri, final MediaPosition pos, Cfg cfg)
       throws WorkflowOperationException {
     final String trackBaseName = FilenameUtils.getBaseName(trackUri.getPath());
     final String format;
     switch (pos.type) {
       case Seconds:
         format = cfg.targetBaseNameFormatSecond.orElse(trackBaseName + "_%.3fs%s");
         break;
       case Percentage:
         format = cfg.targetBaseNameFormatPercent.orElse(trackBaseName + "_%.1fp%s");
         break;
       default:
         throw new WorkflowOperationException("Unexhaustive match");
     }
     return formatFileName(format, pos.position, suffix);
   }
 
   /** Move the extracted <code>image</code> to its final location in the workspace and rename it to <code>fileName</code>. */
   protected void moveToWorkspace(final ImageWorkflowOperationHandler handler, final MediaPackage mp,
       final Attachment image, final String fileName) throws WorkflowOperationException {
     try {
       image.setURI(handler.workspace.moveTo(
           image.getURI(),
           mp.getIdentifier().toString(),
           image.getIdentifier(),
           fileName));
     } catch (Exception e) {
       throw new WorkflowOperationException(e);
     }
   }
 
   /** Start a composer job to extract images from a track at the given positions. */
   protected Job extractImages(
       final ImageWorkflowOperationHandler handler,
       final Track track,
       final EncodingProfile profile,
       final List<MediaPosition> positions,
       Cfg cfg
   ) throws WorkflowOperationException {
     List<Double> seconds = new ArrayList<>();
     for (MediaPosition mediaPosition : positions) {
       seconds.add(toSeconds(track, mediaPosition, cfg.endMargin));
     }
 
     try {
       return handler.composerService.image(track, profile.getIdentifier(), Collections.toDoubleArray(seconds));
     } catch (Exception e) {
       throw new WorkflowOperationException("Error starting image extraction job", e);
     }
   }
 
   // ** ** **
 
   /**
    * Format a filename and make it "safe".
    */
   static String formatFileName(String format, double position, String suffix) {
     return format(Locale.ROOT, format, position, suffix);
   }
 
 
   /** Concat the jobs of a list of extraction objects. */
   private static List<Job> concatJobs(List<Extraction> extractions) {
     List<Job> jobs = new ArrayList<>();
     for (Extraction extraction : extractions) {
       jobs.add(extraction.job);
     }
     return jobs;
   }
 
   /** Get the images (payload) from a job. */
   @SuppressWarnings("unchecked")
   private static List<Attachment> getImages(Job job) throws MediaPackageException, WorkflowOperationException {
     final List<Attachment> images;
     images = (List<Attachment>) MediaPackageElementParser.getArrayFromXml(job.getPayload());
     if (!images.isEmpty()) {
       return images;
     } else {
       throw new WorkflowOperationException("Job did not extract any images");
     }
   }
 
   /** Limit the list of media positions to those that fit into the length of the track. */
   static List<MediaPosition> limit(Track track, List<MediaPosition> positions) {
     final Long duration = track.getDuration();
     // if the video has just one frame (e.g.: MP3-Podcasts) it makes no sense to go to a certain position
     // as the video has only one image at position 0
     if (duration == null || (track.getStreams() != null && Arrays.stream(track.getStreams())
         .filter(stream -> stream instanceof VideoStream)
         .map(org.opencastproject.mediapackage.Stream::getFrameCount)
         .allMatch(frameCount -> frameCount == null || frameCount == 1))) {
       return java.util.Collections.singletonList(new MediaPosition(PositionType.Seconds, 0));
     }
 
     return positions.stream()
         .filter(p -> (PositionType.Seconds.equals(p.type) && p.position >= 0 && p.position < duration)
             || (PositionType.Percentage.equals(p.type) && p.position >= 0 && p.position <= 100))
         .collect(Collectors.toList());
   }
 
   /**
    * Convert a <code>position</code> into seconds in relation to the given track.
    * <em>Attention:</em> The function does not check if the calculated absolute position is within
    * the bounds of the tracks length.
    */
   static double toSeconds(Track track, MediaPosition position, double endMarginMs) throws WorkflowOperationException {
     final long durationMs = track.getDuration() == null ? 0 : track.getDuration();
     final double posMs;
     switch (position.type) {
       case Percentage:
         posMs = durationMs * position.position / 100.0;
         break;
       case Seconds:
         posMs = position.position * 1000.0;
         break;
       default:
         throw new IllegalArgumentException("Unhandled MediaPosition type: " + position.type);
     }
     // limit maximum position to Xms before the end of the video
     return Math.abs(durationMs - posMs) >= endMarginMs
         ? posMs / 1000.0
         : Math.max(0, ((double) durationMs - endMarginMs)) / 1000.0;
   }
 
   // ** ** **
 
   /**
    * Fetch a profile from the composer service. Throw a WorkflowOperationException in case the profile
    * does not exist.
    */
   public static EncodingProfile fetchProfile(ComposerService composerService, String profileName)
       throws WorkflowOperationException {
     EncodingProfile profile = composerService.getProfile(profileName);
     if (profile == null) {
       throw new WorkflowOperationException("Encoding profile '" + profileName + "' was not found");
     }
     return profile;
   }
 
   /**
    * Describes the extraction of a list of images from a track, extracted after a certain encoding profile.
    * Track -> (profile, positions)
    */
   static final class Extraction {
     /** The extraction job. */
     private final Job job;
     /** The track to extract from. */
     private final Track track;
     /** The encoding profile to use for extraction. */
     private final EncodingProfile profile;
     /** Media positions. */
     private final List<MediaPosition> positions;
 
     private Extraction(Job job, Track track, EncodingProfile profile, List<MediaPosition> positions) {
       this.job = job;
       this.track = track;
       this.profile = profile;
       this.positions = positions;
     }
   }
 
   // ** ** **
 
   /**
    * The WOH's configuration options.
    */
   static final class Cfg {
     /** List of source tracks, with duration. */
     private final List<Track> sourceTracks;
     private final List<MediaPosition> positions;
     private final List<EncodingProfile> profiles;
     private final List<MediaPackageElementFlavor> targetImageFlavor;
     private final ConfiguredTagsAndFlavors.TargetTags targetImageTags;
     private final Optional<String> targetBaseNameFormatSecond;
     private final Optional<String> targetBaseNameFormatPercent;
     private final long endMargin;
 
     Cfg(List<Track> sourceTracks,
         List<MediaPosition> positions,
         List<EncodingProfile> profiles,
         List<MediaPackageElementFlavor> targetImageFlavor,
         ConfiguredTagsAndFlavors.TargetTags targetImageTags,
         Optional<String> targetBaseNameFormatSecond,
         Optional<String> targetBaseNameFormatPercent,
         long endMargin) {
       this.sourceTracks = sourceTracks;
       this.positions = positions;
       this.profiles = profiles;
       this.targetImageFlavor = targetImageFlavor;
       this.targetImageTags = targetImageTags;
       this.endMargin = endMargin;
       this.targetBaseNameFormatSecond = targetBaseNameFormatSecond;
       this.targetBaseNameFormatPercent = targetBaseNameFormatPercent;
     }
   }
 
   /** Get and parse the configuration options. */
   private Cfg configure(MediaPackage mp, WorkflowInstance wi) throws WorkflowOperationException {
     WorkflowOperationInstance woi = wi.getCurrentOperation();
     ConfiguredTagsAndFlavors tagsAndFlavors = getTagsAndFlavors(wi,
         Configuration.many, Configuration.many, Configuration.many, Configuration.one);
     final List<EncodingProfile> profiles = getOptConfig(woi, OPT_PROFILES)
         .map(config -> Arrays.asList(config.split(",")))
         .orElse(java.util.Collections.emptyList())
         .stream()
         .map(String::trim)
         .filter(profileName -> !profileName.isEmpty())
         .map(profileName -> {
           try {
             return fetchProfile(composerService, profileName);
           } catch (WorkflowOperationException e) {
             throw new RuntimeException(e);
           }
         })
         .collect(Collectors.toList());
     final ConfiguredTagsAndFlavors.TargetTags targetImageTags = tagsAndFlavors.getTargetTags();
     final List<MediaPackageElementFlavor> targetImageFlavor = tagsAndFlavors.getTargetFlavors();
     final List<Track> sourceTracks;
     {
       // get the source tags
       final List<String> sourceTags = tagsAndFlavors.getSrcTags();
       final List<MediaPackageElementFlavor> sourceFlavors = tagsAndFlavors.getSrcFlavors();
       TrackSelector trackSelector = new TrackSelector();
 
       //add tags and flavors to TrackSelector
       for (String tag : sourceTags) {
         trackSelector.addTag(tag);
       }
       for (MediaPackageElementFlavor flavor : sourceFlavors) {
         trackSelector.addFlavor(flavor);
       }
 
       // select the tracks based on source flavors and tags and skip those that don't have video
       sourceTracks = trackSelector.select(mp, true).stream()
           .filter(Track::hasVideo)
           .collect(Collectors.toList());
     }
     final List<MediaPosition> positions = parsePositions(getConfig(woi, OPT_POSITIONS));
     final long endMargin = getOptConfig(woi, OPT_END_MARGIN)
         .map(Long::parseLong)
         .orElse(END_MARGIN_DEFAULT);
     return new Cfg(sourceTracks,
         positions,
         profiles,
         targetImageFlavor,
         targetImageTags,
         getTargetBaseNameFormat(woi, OPT_TARGET_BASE_NAME_FORMAT_SECOND),
         getTargetBaseNameFormat(woi, OPT_TARGET_BASE_NAME_FORMAT_PERCENT),
         endMargin);
   }
 
   /** Validate a target base name format. */
   private Optional<String> getTargetBaseNameFormat(WorkflowOperationInstance woi, final String formatName)
       throws WorkflowOperationException {
     Optional<String> baseName = getOptConfig(woi, formatName);
     if (baseName.isPresent()) {
       baseName = Optional.ofNullable(validateTargetBaseNameFormat(baseName.get(), formatName));
     }
     return baseName;
   }
 
   static String validateTargetBaseNameFormat(String format, final String formatName) throws WorkflowOperationException {
     boolean valid;
     String name = null;
     try {
       name = formatFileName(format, 15.11, ".png");
       valid = name.contains(".") && name.contains(".png");
     } catch (IllegalFormatException e) {
       valid = false;
     }
     if (!valid || name == null) {
       throw new WorkflowOperationException(format(
           "%s is not a valid format string for config option %s",
           format, formatName));
     }
 
     return name;
   }
 
   // ** ** **
 
   /**
    * Parse media position parameter strings.
    */
   static final class MediaPositionParser {
 
     public static List<MediaPosition> parsePositions(String input) {
       List<MediaPosition> positions = new ArrayList<>();
       int index = 0;
       int length = input.length();
 
       while (index < length) {
         // Skip any separators (whitespace or commas)
         while (index < length && (Character.isWhitespace(input.charAt(index)) || input.charAt(index) == ',')) {
           index++;
         }
 
         if (index >= length) break;
 
         // Parse optional minus sign
         int start = index;
         if (input.charAt(index) == '-') {
           index++;
         }
 
         boolean dotSeen = false;
         while (index < length) {
           char c = input.charAt(index);
           if (Character.isDigit(c)) {
             index++;
           } else if (c == '.' && !dotSeen) {
             dotSeen = true;
             index++;
           } else {
             break;
           }
         }
 
         if (start == index || (input.charAt(start) == '-' && start + 1 == index)) {
           throw new IllegalArgumentException("Expected number at position " + start);
         }
 
         double value = Double.parseDouble(input.substring(start, index));
 
         // Check for optional percent sign
         boolean isPercentage = false;
         if (index < length && input.charAt(index) == '%') {
           isPercentage = true;
           index++;
         }
 
         PositionType type = isPercentage ? PositionType.Percentage : PositionType.Seconds;
         positions.add(new MediaPosition(type, value));
       }
 
       return positions;
     }
   }
 
   private List<MediaPosition> parsePositions(String time) throws WorkflowOperationException {
     final List<MediaPosition> r = MediaPositionParser.parsePositions(time);
     if (!r.isEmpty()) {
       return r;
     } else {
       throw new WorkflowOperationException(format("Cannot parse time string %s.", time));
     }
   }
 
   enum PositionType {
     Percentage, Seconds
   }
 
   /**
    * A position in time in a media file.
    */
   static final class MediaPosition {
     private double position;
     private final PositionType type;
 
     MediaPosition(PositionType type, double position) {
       this.position = position;
       this.type = type;
     }
 
     public void setPosition(double position) {
       this.position = position;
     }
 
     @Override public int hashCode() {
       return Objects.hash(position, type);
     }
 
     @Override public boolean equals(Object that) {
       return (this == that) || (that instanceof MediaPosition && eqFields((MediaPosition) that));
     }
 
     private boolean eqFields(MediaPosition that) {
       return position == that.position && eq(type, that.type);
     }
 
     @Override public String toString() {
       return format("MediaPosition(%s, %s)", type, position);
     }
   }
 
   @Reference
   @Override
   public void setServiceRegistry(ServiceRegistry serviceRegistry) {
     super.setServiceRegistry(serviceRegistry);
   }
 
 }