EDIT

/**

* Copyright (C) 2020 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.cdm.remote.controller.util;

import java.util.ArrayList;

import java.util.HashSet;

import java.util.List;

import java.util.Map;

import java.util.Set;

import org.apache.log4j.Logger;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Component;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.JsonMappingException;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.fasterxml.jackson.databind.type.CollectionType;

import eu.etaxonomy.cdm.api.service.IPreferenceService;

import eu.etaxonomy.cdm.api.service.media.DefaultMediaTransformations;

import eu.etaxonomy.cdm.api.service.media.MediaUriTransformation;

import eu.etaxonomy.cdm.api.service.media.MediaUriTransformationProcessor;

import eu.etaxonomy.cdm.model.media.Media;

import eu.etaxonomy.cdm.model.media.MediaRepresentation;

import eu.etaxonomy.cdm.model.media.MediaRepresentationPart;

import eu.etaxonomy.cdm.model.media.MediaUtils;

import eu.etaxonomy.cdm.model.media.MediaUtils.MissingValueStrategy;

import eu.etaxonomy.cdm.model.metadata.CdmPreference;

import eu.etaxonomy.cdm.model.metadata.CdmPreference.PrefKey;

import eu.etaxonomy.cdm.model.metadata.PreferencePredicate;

import eu.etaxonomy.cdm.model.metadata.PreferenceSubject;

/**

 * Utility service which creates volatile objects which must not be persisted.

 * <p>

 * By now this class provides methods for filtering {@link Media} and {@link MediaRepresentation}s

 * <p>

 * See also {@link MediaUriTransformationProcessor} and {@link MediaUriTransformation}

 *

 * @author a.kohlbecker

 * @since Jul 8, 2020

 */

@Component // not used for component scan, see eu.etaxonomy.cdm.remote.config.CdmRemoteConfiguration

public class MediaToolbox implements IMediaToolbox {

    private static final Logger logger = Logger.getLogger(MediaToolbox.class);

    private List<MediaUriTransformation> transformations = null;

    private Integer mediaRepresentationTransformationsLastHash = null;

    @Autowired

    private IPreferenceService preferenceService;

    @Override

    public List<Media> processAndFilterPreferredMediaRepresentations(Class<? extends MediaRepresentationPart> type, String[] mimeTypes,

            Integer widthOrDuration, Integer height, Integer size, List<Media> mediaList) {

        MediaUriTransformationProcessor mediaTransformationProcessor = new MediaUriTransformationProcessor();

        mediaTransformationProcessor.addAll(readTransformations());

        for(Media media : mediaList) {

            List<MediaRepresentation> newReprs = new ArrayList<>();

            for(MediaRepresentation repr : media.getRepresentations()) {

                for(MediaRepresentationPart part : repr.getParts()) {

                    newReprs.addAll(mediaTransformationProcessor.makeNewMediaRepresentationsFor(part));

                }

            }

            for(MediaRepresentation r : newReprs) {

                media.addRepresentation(r);

            }

        }

        return filterPreferredMediaRepresentations(mediaList, type, mimeTypes, widthOrDuration, height, size);

    }

    @Override

    public MediaRepresentation processAndFindBestMatchingRepresentation(Media media,

            Class<? extends MediaRepresentationPart> type, Integer size, Integer height, Integer widthOrDuration,

            String[] mimeTypes, MissingValueStrategy missingValStrategy) {

        MediaUriTransformationProcessor mediaTransformationProcessor = new MediaUriTransformationProcessor();

        mediaTransformationProcessor.addAll(readTransformations());

        Set<MediaRepresentation> newReprs = new HashSet<>();

        for (MediaRepresentation repr : media.getRepresentations()) {

            for (MediaRepresentationPart part : repr.getParts()) {

                newReprs.addAll(mediaTransformationProcessor.makeNewMediaRepresentationsFor(part));

            }

        }

        newReprs.addAll(media.getRepresentations());

        return MediaUtils.findBestMatchingRepresentation(newReprs, type, size, height, widthOrDuration, mimeTypes, missingValStrategy);

    }

    /**

     * @deprecated needs to be replaced, see https://dev.e-taxonomy.eu/redmine/issues/9160

     */

    @Override

    @Deprecated

    public List<Media> filterPreferredMediaRepresentations(List<Media> mediaList, Class<? extends MediaRepresentationPart> type,

            String[] mimeTypes, Integer widthOrDuration, Integer height, Integer size) {

        Map<Media, MediaRepresentation> mediaRepresentationMap = MediaUtils.findPreferredMedia(mediaList, type, mimeTypes, widthOrDuration, height, size, MediaUtils.MissingValueStrategy.MAX);

        List<Media> filteredMedia = new ArrayList<>(mediaRepresentationMap.size());

        for (Media media : mediaRepresentationMap.keySet()) {

            media.getRepresentations().clear();

            media.addRepresentation(mediaRepresentationMap.get(media));

            media.setId(0); // prevent from persisting the media entity accidentally

            filteredMedia.add(media);

        }

        return filteredMedia;

    }

    /**

     * Read the {@link MediaUriTransformation MediaUriTransformations} from the cdm preferences ({@link PreferencePredicate.MediaRepresentationTransformations}

     * or use the default defined in {@link DefaultMediaTransformations#digilib()}

     *

     */

    private List<MediaUriTransformation> readTransformations() {

        PrefKey key = CdmPreference.NewKey(PreferenceSubject.NewDatabaseInstance(), PreferencePredicate.MediaRepresentationTransformations);

        CdmPreference pref = preferenceService.find(key);

        if(pref != null && pref.getValue() != null) {

            if(mediaRepresentationTransformationsLastHash == null || mediaRepresentationTransformationsLastHash != pref.getValue().hashCode()) {

                // loaded value is different from last value

                ObjectMapper mapper = new ObjectMapper();

                CollectionType javaType = mapper.getTypeFactory()

                        .constructCollectionType(List.class, MediaUriTransformation.class);

                try {

                    transformations = mapper.readValue(pref.getValue(), javaType);

                    mediaRepresentationTransformationsLastHash = pref.getValue().hashCode();

                } catch (JsonMappingException e) {

                    logger.error(e);

                } catch (JsonProcessingException e) {

                    logger.error(e);

                }

            }

        }

        if(transformations == null) {

            transformations = DefaultMediaTransformations.digilib();

        }

        return transformations;

    }

    /**

     * @param trans the list of MediaUriTransformation to be serialized

     * @return the JSON string

     * @throws JsonProcessingException

     */

    static protected String transformationsToJson(List<MediaUriTransformation> trans) throws JsonProcessingException {

      ObjectMapper mapper = new ObjectMapper();

      CollectionType javaType = mapper.getTypeFactory()

              .constructCollectionType(List.class, MediaUriTransformation.class);

      String json = mapper.writerFor(javaType).withDefaultPrettyPrinter().writeValueAsString(trans);

      return json;

    }

    /**

     *

     * @param args

     * @throws JsonProcessingException

     */

    public static void main(String[] args) throws JsonProcessingException {

        System.out.println("Default tansformations for digilib");

        System.out.println("========================================");

        System.out.println(transformationsToJson(DefaultMediaTransformations.digilib()));

    }

}