/*
    * 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.timelinepreviews.ffmpeg;
  
  import org.opencastproject.job.api.AbstractJobProducer;
  import org.opencastproject.job.api.Job;
  import org.opencastproject.mediapackage.Attachment;
  import org.opencastproject.mediapackage.MediaPackageElement;
  import org.opencastproject.mediapackage.MediaPackageElementBuilder;
  import org.opencastproject.mediapackage.MediaPackageElementBuilderFactory;
  import org.opencastproject.mediapackage.MediaPackageElementParser;
  import org.opencastproject.mediapackage.MediaPackageException;
  import org.opencastproject.mediapackage.Track;
  import org.opencastproject.security.api.OrganizationDirectoryService;
  import org.opencastproject.security.api.SecurityService;
  import org.opencastproject.security.api.UserDirectoryService;
  import org.opencastproject.serviceregistry.api.ServiceRegistry;
  import org.opencastproject.serviceregistry.api.ServiceRegistryException;
  import org.opencastproject.timelinepreviews.api.TimelinePreviewsException;
  import org.opencastproject.timelinepreviews.api.TimelinePreviewsService;
  import org.opencastproject.util.IoSupport;
  import org.opencastproject.util.LoadUtil;
  import org.opencastproject.util.MimeTypes;
  import org.opencastproject.util.NotFoundException;
  import org.opencastproject.util.UnknownFileTypeException;
  import org.opencastproject.workspace.api.Workspace;
  
  import org.apache.commons.io.FileUtils;
  import org.apache.commons.io.FilenameUtils;
  import org.apache.commons.lang3.StringUtils;
  import org.osgi.service.cm.ConfigurationException;
  import org.osgi.service.cm.ManagedService;
  import org.osgi.service.component.ComponentContext;
  import org.osgi.service.component.annotations.Component;
  import org.osgi.service.component.annotations.Reference;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.net.URI;
  import java.util.Arrays;
  import java.util.Dictionary;
  import java.util.List;
  import java.util.UUID;
  
  /**
   * Media analysis plugin that takes a video stream and generates preview images that can be shown on the timeline.
   * This will be done using FFmpeg.
   */
  @Component(
      immediate = true,
      service = { TimelinePreviewsService.class,ManagedService.class },
      property = {
          "service.description=TimelinePreviews Service"
      }
  )
  public class TimelinePreviewsServiceImpl extends AbstractJobProducer implements
      TimelinePreviewsService, ManagedService {
  
    /** Resulting collection in the working file repository */
    public static final String COLLECTION_ID = "timelinepreviews";
  
    /** List of available operations on jobs */
    protected enum Operation {
      TimelinePreview
    };
  
    /** Path to the executable */
    protected String binary = FFMPEG_BINARY_DEFAULT;
  
    /** The key to look for in the service configuration file to override the DEFAULT_FFMPEG_BINARY */
    public static final String FFMPEG_BINARY_CONFIG = "org.opencastproject.composer.ffmpeg.path";
  
    /** The default path to the FFmpeg binary */
    public static final String FFMPEG_BINARY_DEFAULT = "ffmpeg";
 
   /** Name of the constant used to retrieve the horizontal resolution */
   public static final String OPT_RESOLUTION_X = "resolutionX";
 
   /** Default value for the horizontal resolution */
   public static final int DEFAULT_RESOLUTION_X = 160;
 
   /** Name of the constant used to retrieve the vertical resolution */
   public static final String OPT_RESOLUTION_Y = "resolutionY";
 
   /** Default value for the vertical resolution */
   public static final int DEFAULT_RESOLUTION_Y = -1;
 
   /** Name of the constant used to retrieve the output file format */
   public static final String OPT_OUTPUT_FORMAT = "outputFormat";
 
   /** Default value for the format of the output image file */
   public static final String DEFAULT_OUTPUT_FORMAT = ".png";
 
   /** Name of the constant used to retrieve the mimetype */
   public static final String OPT_MIMETYPE = "mimetype";
 
   /** Default value for the mimetype of the generated image */
   public static final String DEFAULT_MIMETYPE = "image/png";
 
 
   /** The default job load of a timeline previews job */
   public static final float DEFAULT_TIMELINEPREVIEWS_JOB_LOAD = 0.1f;
 
   /** The key to look for in the service configuration file to override the DEFAULT_TIMELINEPREVIEWS_JOB_LOAD */
   public static final String TIMELINEPREVIEWS_JOB_LOAD_KEY = "job.load.timelinepreviews";
 
   /** The load introduced on the system by creating a caption job */
   private float timelinepreviewsJobLoad = DEFAULT_TIMELINEPREVIEWS_JOB_LOAD;
 
   /** The logging facility */
   protected static final Logger logger = LoggerFactory
       .getLogger(TimelinePreviewsServiceImpl.class);
 
   /** The horizontal resolution of a single preview image */
   protected int resolutionX = DEFAULT_RESOLUTION_X;
 
   /** The vertical resolution of a single preview image */
   protected int resolutionY = DEFAULT_RESOLUTION_Y;
 
   /** The file format of the generated preview images file */
   protected String outputFormat = DEFAULT_OUTPUT_FORMAT;
 
   /** The mimetype that will be set for the generated Attachment containing the timeline previews image */
   protected String mimetype = DEFAULT_MIMETYPE;
 
 
   /** Reference to the receipt service */
   protected ServiceRegistry serviceRegistry = null;
 
   /** The workspace to use when retrieving remote media files */
   protected Workspace workspace = null;
 
   /** The security service */
   protected SecurityService securityService = null;
 
   /** The user directory service */
   protected UserDirectoryService userDirectoryService = null;
 
   /** The organization directory service */
   protected OrganizationDirectoryService organizationDirectoryService = null;
 
   /**
    * Creates a new instance of the timeline previews service.
    */
   public TimelinePreviewsServiceImpl() {
     super(JOB_TYPE);
     this.binary = FFMPEG_BINARY_DEFAULT;
   }
 
   @Override
   public void activate(ComponentContext cc) {
     super.activate(cc);
     logger.info("Activate ffmpeg timeline previews service");
     final String path = cc.getBundleContext().getProperty(FFMPEG_BINARY_CONFIG);
     this.binary = path == null ? FFMPEG_BINARY_DEFAULT : path;
     logger.debug("Configuration {}: {}", FFMPEG_BINARY_CONFIG, FFMPEG_BINARY_DEFAULT);
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.osgi.service.cm.ManagedService#updated(java.util.Dictionary)
    */
   @Override
   public void updated(Dictionary<String, ?> properties) throws ConfigurationException {
     if (properties == null) {
       return;
     }
     logger.debug("Configuring the timeline previews service");
 
     // Horizontal resolution
     if (properties.get(OPT_RESOLUTION_X) != null) {
       String res = (String) properties.get(OPT_RESOLUTION_X);
       try {
         resolutionX = Integer.parseInt(res);
         logger.info("Horizontal resolution set to {} pixels", resolutionX);
       } catch (Exception e) {
         throw new ConfigurationException(OPT_RESOLUTION_X, "Found illegal value '" + res
                 + "' for timeline previews horizontal resolution");
       }
     }
     // Vertical resolution
     if (properties.get(OPT_RESOLUTION_Y) != null) {
       String res = (String) properties.get(OPT_RESOLUTION_Y);
       try {
         resolutionY = Integer.parseInt(res);
         logger.info("Vertical resolution set to {} pixels", resolutionY);
       } catch (Exception e) {
         throw new ConfigurationException(OPT_RESOLUTION_Y, "Found illegal value '" + res
                 + "' for timeline previews vertical resolution");
       }
     }
     // Output file format
     if (properties.get(OPT_OUTPUT_FORMAT) != null) {
       String format = (String) properties.get(OPT_OUTPUT_FORMAT);
       try {
         outputFormat = format;
         logger.info("Output file format set to \"{}\"", outputFormat);
       } catch (Exception e) {
         throw new ConfigurationException(OPT_OUTPUT_FORMAT, "Found illegal value '" + format
                 + "' for timeline previews output file format");
       }
     }
     // Output mimetype
     if (properties.get(OPT_MIMETYPE) != null) {
       String type = (String) properties.get(OPT_MIMETYPE);
       try {
         mimetype = type;
         logger.info("Mime type set to \"{}\"", mimetype);
       } catch (Exception e) {
         throw new ConfigurationException(OPT_MIMETYPE, "Found illegal value '" + type
                 + "' for timeline previews mimetype");
       }
     }
 
     timelinepreviewsJobLoad = LoadUtil.getConfiguredLoadValue(properties, TIMELINEPREVIEWS_JOB_LOAD_KEY,
             DEFAULT_TIMELINEPREVIEWS_JOB_LOAD, serviceRegistry);
   }
 
   @Override
   public Job createTimelinePreviewImages(Track track, int imageCount) throws TimelinePreviewsException,
           MediaPackageException {
     try {
       List<String> parameters = Arrays.asList(MediaPackageElementParser.getAsXml(track), Integer.toString(imageCount));
 
       return serviceRegistry.createJob(JOB_TYPE,
           Operation.TimelinePreview.toString(),
           parameters,
           timelinepreviewsJobLoad);
     } catch (ServiceRegistryException e) {
       throw new TimelinePreviewsException("Unable to create timelinepreviews job", e);
     }
   }
 
   /**
    * Starts generation of timeline preview images for the given video track
    * and returns an attachment containing one image that contains all the
    * timeline preview images.
    *
    * @param job
    * @param track the element to analyze
    * @param imageCount number of preview images that will be generated
    * @return an attachment containing the resulting timeline previews image
    * @throws TimelinePreviewsException
    * @throws org.opencastproject.mediapackage.MediaPackageException
    */
   protected Attachment generatePreviewImages(Job job, Track track, int imageCount)
           throws TimelinePreviewsException, MediaPackageException {
 
     // Make sure the element can be analyzed using this analysis implementation
     if (!track.hasVideo()) {
       logger.error("Element {} is not a video track", track.getIdentifier());
       throw new TimelinePreviewsException("Element is not a video track");
     }
 
     try {
 
       if (track.getDuration() == null) {
         throw new MediaPackageException("Track " + track + " does not have a duration");
       }
 
       double duration = track.getDuration() / 1000.0;
       double seconds = duration / (double)(imageCount);
       seconds = seconds <= 0.0 ? 1.0 : seconds;
 
       // calculate number of tiles for row and column in tiled image
       int imageSize = (int) Math.ceil(Math.sqrt(imageCount));
 
       Attachment composedImage = createPreviewsFFmpeg(track, seconds, resolutionX, resolutionY, imageSize, imageSize,
               duration);
 
 
       if (composedImage == null) {
         throw new IllegalStateException("Unable to compose image");
       }
 
       // Set the mimetype
       try {
         composedImage.setMimeType(MimeTypes.parseMimeType(mimetype));
       } catch (IllegalArgumentException e) {
         logger.warn("Invalid mimetype provided for timeline previews image");
         try  {
           composedImage.setMimeType(MimeTypes.fromURI(composedImage.getURI()));
         } catch (UnknownFileTypeException ex) {
           logger.warn("No valid mimetype could be found for timeline previews image");
         }
       }
 
       composedImage.getProperties().put("imageCount", String.valueOf(imageCount));
 
       return composedImage;
 
     } catch (Exception e) {
       logger.warn("Error creating timeline preview images for " + track, e);
       if (e instanceof TimelinePreviewsException) {
         throw (TimelinePreviewsException) e;
       } else {
         throw new TimelinePreviewsException(e);
       }
     }
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.job.api.AbstractJobProducer#process(org.opencastproject.job.api.Job)
    */
   @Override
   protected String process(Job job) throws Exception {
     Operation op = null;
     String operation = job.getOperation();
     List<String> arguments = job.getArguments();
     try {
       op = Operation.valueOf(operation);
       switch (op) {
         case TimelinePreview:
           Track track = (Track) MediaPackageElementParser
               .getFromXml(arguments.get(0));
           int imageCount = Integer.parseInt(arguments.get(1));
           Attachment timelinePreviewsMpe = generatePreviewImages(job, track, imageCount);
           return MediaPackageElementParser.getAsXml(timelinePreviewsMpe);
         default:
           throw new IllegalStateException("Don't know how to handle operation '" + operation + "'");
       }
     } catch (IllegalArgumentException e) {
       throw new ServiceRegistryException("This service can't handle operations of type '" + op + "'", e);
     } catch (IndexOutOfBoundsException e) {
       throw new ServiceRegistryException("This argument list for operation '" + op + "' does not meet expectations", e);
     } catch (Exception e) {
       throw new ServiceRegistryException("Error handling operation '" + op + "'", e);
     }
   }
 
   /**
    * Executes the FFmpeg command to generate a timeline previews image
    *
    * @param track the track to generate the timeline previews image for
    * @param seconds the length of a segment that one preview image should represent
    * @param width the width of a single preview image
    * @param height the height of a single preview image
    * @param tileX the horizontal number of preview images that are stored in the timeline previews image
    * @param tileY the vertical number of preview images that are stored in the timeline previews image
    * @param duration the duration for which preview images should be generated
    * @return an attachment containing the timeline previews image
    * @throws TimelinePreviewsException
    */
   protected Attachment createPreviewsFFmpeg(Track track, double seconds, int width, int height, int tileX, int tileY,
           double duration) throws TimelinePreviewsException {
 
     // copy source file into workspace
     File mediaFile;
     try {
       mediaFile = workspace.get(track.getURI());
     } catch (NotFoundException e) {
       throw new TimelinePreviewsException(
           "Error finding the media file in the workspace", e);
     } catch (IOException e) {
       throw new TimelinePreviewsException(
           "Error reading the media file in the workspace", e);
     }
 
     String imageFilePath = FilenameUtils.removeExtension(mediaFile.getAbsolutePath()) + '_' + UUID.randomUUID()
                            + "_timelinepreviews" + outputFormat;
     int exitCode = 1;
     String[] command = new String[] {
         binary,
         "-loglevel", "error",
         "-t", String.valueOf(duration - seconds / 2.0),
         // For longer videos, this operation only considers keyframes. This
         // significantly speeds up this command. The difference in output is
         // minimal and not relevant for the user. Nothing would crash without
         // this duration check: short videos would just repeat keyframes in the
         // output image, making the preview less useful.
         "-skip_frame", duration > 15 * 60.0 ? "nokey" : "default",
         "-i", mediaFile.getAbsolutePath(),
         "-vf", "fps=1/" + seconds + ",scale=" + width + ":" + height + ",tile=" + tileX + "x" + tileY,
         imageFilePath
     };
 
     logger.debug("Start timeline previews ffmpeg process: {}", StringUtils.join(command, " "));
     logger.info("Create timeline preview images file for track '{}' at {}", track.getIdentifier(), imageFilePath);
 
     ProcessBuilder pbuilder = new ProcessBuilder(command);
 
     pbuilder.redirectErrorStream(true);
     Process ffmpegProcess = null;
     exitCode = 1;
     BufferedReader errStream = null;
     try {
       ffmpegProcess = pbuilder.start();
 
       errStream = new BufferedReader(new InputStreamReader(ffmpegProcess.getInputStream()));
       String line = errStream.readLine();
       while (line != null) {
         logger.error("FFmpeg error: " + line);
         line = errStream.readLine();
       }
       exitCode = ffmpegProcess.waitFor();
     } catch (IOException ex) {
       throw new TimelinePreviewsException("Starting ffmpeg process failed", ex);
     } catch (InterruptedException ex) {
       throw new TimelinePreviewsException("Timeline preview creation was unexpectedly interrupted", ex);
     } finally {
       IoSupport.closeQuietly(ffmpegProcess);
       IoSupport.closeQuietly(errStream);
       if (exitCode != 0) {
         try {
           FileUtils.forceDelete(new File(imageFilePath));
         } catch (IOException e) {
           // it is ok, no output file was generated by ffmpeg
         }
       }
     }
 
     if (exitCode != 0) {
       throw new TimelinePreviewsException("Generating timeline preview for track " + track.getIdentifier()
               + " failed: ffmpeg process exited abnormally with exit code " + exitCode);
     }
 
     // put timeline previews image into workspace
     FileInputStream timelinepreviewsFileInputStream = null;
     URI previewsFileUri = null;
     try {
       timelinepreviewsFileInputStream = new FileInputStream(imageFilePath);
       previewsFileUri = workspace.putInCollection(COLLECTION_ID,
               FilenameUtils.getName(imageFilePath), timelinepreviewsFileInputStream);
       logger.info("Copied the created timeline preview images file to the workspace {}", previewsFileUri.toString());
     } catch (FileNotFoundException ex) {
       throw new TimelinePreviewsException(
               String.format("Timeline previews image file '%s' not found", imageFilePath), ex);
     } catch (IOException ex) {
       throw new TimelinePreviewsException(
               String.format("Can't write timeline preview images file '%s' to workspace", imageFilePath), ex);
     } catch (IllegalArgumentException ex) {
       throw new TimelinePreviewsException(ex);
     } finally {
       IoSupport.closeQuietly(timelinepreviewsFileInputStream);
       logger.info("Deleted local timeline preview images file at {}", imageFilePath);
       FileUtils.deleteQuietly(new File(imageFilePath));
     }
 
     // create media package element
     MediaPackageElementBuilder mpElementBuilder = MediaPackageElementBuilderFactory.newInstance().newElementBuilder();
     // it is up to the workflow operation handler to set the attachment flavor
     Attachment timelinepreviewsMpe = (Attachment) mpElementBuilder.elementFromURI(
             previewsFileUri, MediaPackageElement.Type.Attachment, track.getFlavor());
 
     // add reference to track
     timelinepreviewsMpe.referTo(track);
 
     // add additional properties to attachment
     timelinepreviewsMpe.getProperties().put("imageSizeX", String.valueOf(tileX));
     timelinepreviewsMpe.getProperties().put("imageSizeY", String.valueOf(tileY));
     timelinepreviewsMpe.getProperties().put("resolutionX", String.valueOf(resolutionX));
     timelinepreviewsMpe.getProperties().put("resolutionY", String.valueOf(resolutionY));
 
     // set the flavor and an ID
     timelinepreviewsMpe.setFlavor(track.getFlavor());
     timelinepreviewsMpe.generateIdentifier();
 
     return timelinepreviewsMpe;
   }
 
   /**
    * Sets the workspace
    *
    * @param workspace
    *            an instance of the workspace
    */
   @Reference
   protected void setWorkspace(Workspace workspace) {
     this.workspace = workspace;
   }
 
   /**
    * Sets the receipt service
    *
    * @param serviceRegistry
    *            the service registry
    */
   @Reference
   protected void setServiceRegistry(ServiceRegistry serviceRegistry) {
     this.serviceRegistry = serviceRegistry;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.job.api.AbstractJobProducer#getServiceRegistry()
    */
   @Override
   protected ServiceRegistry getServiceRegistry() {
     return serviceRegistry;
   }
 
   /**
    * Callback for setting the security service.
    *
    * @param securityService
    *            the securityService to set
    */
   @Reference
   public void setSecurityService(SecurityService securityService) {
     this.securityService = securityService;
   }
 
   /**
    * Callback for setting the user directory service.
    *
    * @param userDirectoryService
    *            the userDirectoryService to set
    */
   @Reference
   public void setUserDirectoryService(
       UserDirectoryService userDirectoryService) {
     this.userDirectoryService = userDirectoryService;
   }
 
   /**
    * Sets a reference to the organization directory service.
    *
    * @param organizationDirectory
    *            the organization directory
    */
   @Reference
   public void setOrganizationDirectoryService(
       OrganizationDirectoryService organizationDirectory) {
     this.organizationDirectoryService = organizationDirectory;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.job.api.AbstractJobProducer#getSecurityService()
    */
   @Override
   protected SecurityService getSecurityService() {
     return securityService;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.job.api.AbstractJobProducer#getUserDirectoryService()
    */
   @Override
   protected UserDirectoryService getUserDirectoryService() {
     return userDirectoryService;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.job.api.AbstractJobProducer#getOrganizationDirectoryService()
    */
   @Override
   protected OrganizationDirectoryService getOrganizationDirectoryService() {
     return organizationDirectoryService;
   }
 
 }