/**
 * Copyright (c) 2011, The University of Southampton and the individual contributors.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 *   *  Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *
 *   *  Redistributions in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the documentation
 *      and/or other materials provided with the distribution.
 *
 *   *  Neither the name of the University of Southampton nor the names of its
 *      contributors may be used to endorse or promote products derived from this
 *      software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.openimaj.image.dataset;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.xml.parsers.ParserConfigurationException;

import org.openimaj.data.dataset.ReadableListDataset;
import org.openimaj.image.Image;
import org.openimaj.io.HttpUtils;
import org.openimaj.io.InputStreamObjectReader;
import org.openimaj.util.api.auth.common.FlickrAPIToken;

import com.aetrion.flickr.Flickr;
import com.aetrion.flickr.REST;
import com.aetrion.flickr.collections.CollectionsInterface;
import com.aetrion.flickr.collections.CollectionsSearchParameters;
import com.aetrion.flickr.photos.Extras;
import com.aetrion.flickr.photos.Photo;
import com.aetrion.flickr.photos.PhotoList;
import com.aetrion.flickr.photosets.PhotosetsInterface;

/**
 * Class to dynamically create image datasets from flickr through various api
 * calls.
 * 
 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 * 
 * @param <IMAGE>
 *            The type of {@link Image} instance held by the dataset.
 */
public class FlickrImageDataset<IMAGE extends Image<?, IMAGE>> extends ReadableListDataset<IMAGE, InputStream> {
        /**
         * Possible sizes of image from flickr.
         * 
         * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
         */
        public enum Size {
                /**
                 * The original uploaded size
                 */
                Original {
                        @Override
                        protected URL getURL(Photo photo) {
                                try {
                                        return new URL(photo.getOriginalUrl());
                                } catch (final Exception e) {
                                        throw new RuntimeException(e);
                                }
                        }
                },
                /**
                 * Large size
                 */
                Large {
                        @Override
                        protected URL getURL(Photo photo) {
                                try {
                                        return new URL(photo.getLargeUrl());
                                } catch (final Exception e) {
                                        throw new RuntimeException(e);
                                }
                        }
                },
                /**
                 * Medium size
                 */
                Medium {
                        @Override
                        protected URL getURL(Photo photo) {
                                try {
                                        return new URL(photo.getMediumUrl());
                                } catch (final Exception e) {
                                        throw new RuntimeException(e);
                                }
                        }
                },
                /**
                 * Small size
                 */
                Small {
                        @Override
                        protected URL getURL(Photo photo) {
                                try {
                                        return new URL(photo.getSmallUrl());
                                } catch (final Exception e) {
                                        throw new RuntimeException(e);
                                }
                        }
                },
                /**
                 * Thumbnail size
                 */
                Thumbnail {
                        @Override
                        protected URL getURL(Photo photo) {
                                try {
                                        return new URL(photo.getThumbnailUrl());
                                } catch (final Exception e) {
                                        throw new RuntimeException(e);
                                }
                        }
                },
                /**
                 * Square thumbnail size
                 */
                Square {
                        @Override
                        protected URL getURL(Photo photo) {
                                try {
                                        return new URL(photo.getSmallSquareUrl());
                                } catch (final Exception e) {
                                        throw new RuntimeException(e);
                                }
                        }
                };

                protected abstract URL getURL(Photo photo);
        }

        private final static Pattern GALLERY_URL_PATTERN = Pattern.compile(".*/photos/.*/galleries/[0-9]*(/|$)");
        private final static Pattern PHOTOSET_URL_PATTERN = Pattern.compile(".*/photos/.*/sets/([0-9]*)(/|$)");
        private final static Pattern COLLECTION_URL_PATTERN = Pattern.compile(".*/photos/(.*)/collections/([0-9]*)(/|$)");

        protected List<Photo> photos;
        protected Size targetSize = Size.Medium;

        protected FlickrImageDataset(InputStreamObjectReader<IMAGE> reader, List<Photo> photos) {
                super(reader);

                this.photos = photos;
        }

        /**
         * Set the size of the images that this dataset produces.
         * 
         * @param size
         *            the size
         */
        public void setImageSize(Size size) {
                this.targetSize = size;
        }

        /**
         * Get the size of the images that this dataset produces.
         * 
         * @return the size of the returned images
         */
        public Size getImageSize() {
                return targetSize;
        }

        /**
         * Get the underlying flickr {@link Photo} objects.
         * 
         * @return the underlying list of {@link Photo}s.
         */
        public List<Photo> getPhotos() {
                return photos;
        }

        /**
         * Get the a specific underlying flickr {@link Photo} object corresponding
         * to a particular image instance.
         * 
         * @param index
         *            the index of the instance
         * 
         * @return the underlying {@link Photo} corresponding to the given instance
         *         index.
         */
        public Photo getPhoto(int index) {
                return photos.get(index);
        }

        @Override
        public IMAGE getInstance(int index) {
                return read(photos.get(index));
        }

        @Override
        public int numInstances() {
                return photos.size();
        }

        @Override
        public String getID(int index) {
                return targetSize.getURL(photos.get(index)).toString();
        }

        private IMAGE read(Photo next) {
                if (next == null)
                        return null;

                InputStream stream = null;
                try {
                        stream = HttpUtils.readURL(targetSize.getURL(next));

                        return reader.read(stream);
                } catch (final IOException e) {
                        throw new RuntimeException(e);
                } finally {
                        try {
                                if (stream != null)
                                        stream.close();
                        } catch (final IOException e) {
                                // ignore
                        }
                }
        }

        @Override
        public Iterator<IMAGE> iterator() {
                return new Iterator<IMAGE>() {
                        Iterator<Photo> internal = photos.iterator();

                        @Override
                        public boolean hasNext() {
                                return internal.hasNext();
                        }

                        @Override
                        public IMAGE next() {
                                return read(internal.next());
                        }

                        @Override
                        public void remove() {
                                internal.remove();
                        }
                };
        }

        @Override
        public String toString() {
                return String.format("%s(%d images)", this.getClass().getName(), this.photos.size());
        }

        /**
         * Create an image dataset from the flickr gallery, photoset or collection
         * at the given url.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param url
         *            the url of the collection/gallery/photo-set
         * @return a {@link FlickrImageDataset} created from the given url
         * @throws Exception
         *             if an error occurs
         */
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> create(InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        URL url) throws Exception
        {
                return create(reader, token, url, 0);
        }

        /**
         * Create an image dataset by searching flickr with the given search terms.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param searchTerms
         *            the search terms; space separated. Prepending a term with a
         *            "-" means that the term should not appear.
         * @return a {@link FlickrImageDataset} created from the given url
         * @throws Exception
         *             if an error occurs
         */
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> create(InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token, String searchTerms) throws Exception
        {
                return create(reader, token, searchTerms, 0);
        }

        /**
         * Create an image dataset by searching flickr with the given search terms.
         * The number of images can be limited to a subset.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param searchTerms
         *            the search terms; space separated. Prepending a term with a
         *            "-" means that the term should not appear.
         * @param number
         *            the maximum number of images to add to the dataset. Setting to
         *            0 or less will attempt to use all the images.
         * @return a {@link FlickrImageDataset} created from the given url
         * @throws Exception
         *             if an error occurs
         */
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> create(InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        String searchTerms, int number) throws Exception
        {
                final com.aetrion.flickr.photos.SearchParameters params = new com.aetrion.flickr.photos.SearchParameters();
                params.setText(searchTerms);

                return createFromSearch(reader, token, params, number);
        }

        /**
         * Create an image dataset from the flickr gallery, photoset or collection
         * at the given url. The number of images can be limited to a subset.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param url
         *            the url of the collection/gallery/photo-set
         * @param number
         *            the maximum number of images to add to the dataset. Setting to
         *            0 or less will attempt to use all the images.
         * @return a {@link FlickrImageDataset} created from the given url
         * @throws Exception
         *             if an error occurs
         */
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> create(InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        URL url, int number) throws Exception
        {
                final String urlString = url.toString();

                if (GALLERY_URL_PATTERN.matcher(urlString).matches()) {
                        return fromGallery(reader, token, urlString, number);
                } else if (PHOTOSET_URL_PATTERN.matcher(urlString).matches()) {
                        return fromPhotoset(reader, token, urlString, number);
                } else if (COLLECTION_URL_PATTERN.matcher(urlString).matches()) {
                        return fromCollection(reader, token, urlString, number);
                }

                throw new IllegalArgumentException("Unknown URL type " + urlString);
        }

        private static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> fromGallery(
                        InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        String urlString, int number) throws Exception
        {
                final Flickr flickr = makeFlickr(token);

                final String galleryId = flickr.getUrlsInterface().lookupGallery(urlString);

                final com.aetrion.flickr.galleries.SearchParameters params = new com.aetrion.flickr.galleries.SearchParameters();
                params.setGalleryId(galleryId);

                return createFromGallery(reader, token, params, number);
        }

        private static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> fromPhotoset(
                        InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        String urlString, int number) throws Exception
        {
                final Matcher matcher = PHOTOSET_URL_PATTERN.matcher(urlString);
                matcher.find();
                final String setId = matcher.group(1);

                return createFromPhotoset(reader, token, setId, number);
        }

        private static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> fromCollection(
                        InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        String urlString, int number) throws Exception
        {
                final Flickr flickr = makeFlickr(token);

                final Matcher matcher = COLLECTION_URL_PATTERN.matcher(urlString);
                matcher.find();
                final String userName = matcher.group(1);
                final String collectionsId = matcher.group(2);

                final CollectionsSearchParameters params = new CollectionsSearchParameters();
                params.setCollectionId(collectionsId);
                params.setUserId(flickr.getPeopleInterface().findByUsername(userName).getId());

                return createFromCollection(reader, token, params, number);
        }

        /**
         * Create an image dataset from a flickr gallery with the specified
         * parameters.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param params
         *            the parameters describing the gallery and any additional
         *            constraints.
         * @return a {@link FlickrImageDataset} created from the gallery described
         *         by the given parameters
         * @throws Exception
         *             if an error occurs
         */
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> createFromGallery(
                        InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        com.aetrion.flickr.galleries.SearchParameters params) throws Exception
        {
                return createFromGallery(reader, token, params, 0);
        }

        /**
         * Create an image dataset from a flickr gallery with the specified
         * parameters. The number of images can be limited to a subset.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param params
         *            the parameters describing the gallery and any additional
         *            constraints.
         * @param number
         *            the maximum number of images to add to the dataset. Setting to
         *            0 or less will attempt to use all the images.
         * @return a {@link FlickrImageDataset} created from the gallery described
         *         by the given parameters
         * @throws Exception
         *             if an error occurs
         */
        @SuppressWarnings("unchecked")
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> createFromGallery(
                        InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        com.aetrion.flickr.galleries.SearchParameters params, int number) throws Exception
        {
                final Flickr flickr = makeFlickr(token);

                params.setExtras(Extras.ALL_EXTRAS);

                List<Photo> photos = new ArrayList<Photo>();
                final PhotoList first = flickr.getGalleriesInterface().getPhotos(params, 250, 0);
                photos.addAll(first);

                if (number > 0)
                        number = Math.min(number, first.getTotal());

                for (int page = 1, n = photos.size(); n < number; page++) {
                        final PhotoList result = flickr.getGalleriesInterface().getPhotos(params, 250, page);
                        photos.addAll(result);
                        n += result.size();
                }

                if (number > 0 && number < photos.size())
                        photos = photos.subList(0, number);

                return new FlickrImageDataset<IMAGE>(reader, photos);
        }

        /**
         * Create an image dataset from a flickr photoset.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param setId
         *            the photoset identifier
         * @return a {@link FlickrImageDataset} created from the gallery described
         *         by the given parameters
         * @throws Exception
         *             if an error occurs
         */
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> createFromPhotoset(
                        InputStreamObjectReader<IMAGE> reader, FlickrAPIToken token, String setId) throws Exception
        {
                return createFromPhotoset(reader, token, setId, 0);
        }

        /**
         * Create an image dataset from a flickr photoset. The number of images can
         * be limited to a subset.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param setId
         *            the photoset identifier
         * @param number
         *            the maximum number of images to add to the dataset. Setting to
         *            0 or less will attempt to use all the images.
         * @return a {@link FlickrImageDataset} created from the gallery described
         *         by the given parameters
         * @throws Exception
         *             if an error occurs
         */
        @SuppressWarnings("unchecked")
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> createFromPhotoset(
                        InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        String setId, int number) throws Exception
        {
                final Flickr flickr = makeFlickr(token);

                final PhotosetsInterface setsInterface = flickr.getPhotosetsInterface();

                List<Photo> photos = new ArrayList<Photo>();
                final PhotoList first = setsInterface.getPhotos(setId, Extras.ALL_EXTRAS, 0, 250, 0);
                photos.addAll(first);

                if (number > 0)
                        number = Math.min(number, first.getTotal());

                for (int page = 1, n = photos.size(); n < number; page++) {
                        final PhotoList result = setsInterface.getPhotos(setId, Extras.ALL_EXTRAS, 0, 250, page);
                        photos.addAll(result);
                        n += result.size();
                }

                if (number > 0 && number < photos.size())
                        photos = photos.subList(0, number);

                return new FlickrImageDataset<IMAGE>(reader, photos);
        }

        /**
         * Create an image dataset from a flickr collection with the specified
         * parameters.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param params
         *            the parameters describing the gallery and any additional
         *            constraints.
         * @return a {@link FlickrImageDataset} created from the gallery described
         *         by the given parameters
         * @throws Exception
         *             if an error occurs
         */
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> createFromCollection(
                        InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        com.aetrion.flickr.collections.CollectionsSearchParameters params) throws Exception
        {
                return createFromCollection(reader, token, params, 0);
        }

        /**
         * Create an image dataset from a flickr collection with the specified
         * parameters. The number of images can be limited to a subset.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param params
         *            the parameters describing the gallery and any additional
         *            constraints.
         * @param number
         *            the maximum number of images to add to the dataset. Setting to
         *            0 or less will attempt to use all the images.
         * @return a {@link FlickrImageDataset} created from the gallery described
         *         by the given parameters
         * @throws Exception
         *             if an error occurs
         */
        @SuppressWarnings("unchecked")
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> createFromCollection(
                        InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        com.aetrion.flickr.collections.CollectionsSearchParameters params, int number) throws Exception
        {
                final Flickr flickr = makeFlickr(token);

                params.setExtras(Extras.ALL_EXTRAS);

                List<Photo> photos = new ArrayList<Photo>();
                final CollectionsInterface collectionsInterface = flickr.getCollectionsInterface();
                final PhotoList photoList = collectionsInterface.getTree(params).getPhotoUrls(flickr.getPhotosetsInterface());
                photos.addAll(photoList);

                if (number > 0 && number < photos.size())
                        photos = photos.subList(0, number);

                return new FlickrImageDataset<IMAGE>(reader, photos);
        }

        /**
         * Create an image dataset from a flickr search with the specified
         * parameters.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param params
         *            the parameters describing the gallery and any additional
         *            constraints.
         * @return a {@link FlickrImageDataset} created from the gallery described
         *         by the given parameters
         * @throws Exception
         *             if an error occurs
         */
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> createFromSearch(
                        InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        com.aetrion.flickr.photos.SearchParameters params) throws Exception
        {
                return createFromSearch(reader, token, params, 0);
        }

        /**
         * Create an image dataset from a flickr search with the specified
         * parameters. The number of images can be limited to a subset.
         * 
         * @param reader
         *            the reader with which to load the images
         * @param token
         *            the flickr api authentication token
         * @param params
         *            the parameters describing the gallery and any additional
         *            constraints.
         * @param number
         *            the maximum number of images to add to the dataset. Setting to
         *            0 or less will attempt to use all the images.
         * @return a {@link FlickrImageDataset} created from the gallery described
         *         by the given parameters
         * @throws Exception
         *             if an error occurs
         */
        @SuppressWarnings("unchecked")
        public static <IMAGE extends Image<?, IMAGE>> FlickrImageDataset<IMAGE> createFromSearch(
                        InputStreamObjectReader<IMAGE> reader,
                        FlickrAPIToken token,
                        com.aetrion.flickr.photos.SearchParameters params, int number) throws Exception
        {
                final Flickr flickr = makeFlickr(token);

                params.setExtras(Extras.ALL_EXTRAS);

                List<Photo> photos = new ArrayList<Photo>();
                final PhotoList first = flickr.getPhotosInterface().search(params, 250, 0);
                photos.addAll(first);

                if (number > 0)
                        number = Math.min(number, first.getTotal());

                for (int page = 1, n = photos.size(); n < number; page++) {
                        final PhotoList result = flickr.getPhotosInterface().search(params, 250, page);
                        photos.addAll(result);
                        n += result.size();
                }

                if (number > 0 && number < photos.size())
                        photos = photos.subList(0, number);

                return new FlickrImageDataset<IMAGE>(reader, photos);
        }

        private static Flickr makeFlickr(FlickrAPIToken token) throws ParserConfigurationException {
                if (token.secret == null)
                        return new Flickr(token.apikey, new REST(Flickr.DEFAULT_HOST));
                return new Flickr(token.apikey, token.secret, new REST(Flickr.DEFAULT_HOST));
        }
}