/*
    * 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.publication.youtube;
  
  import org.opencastproject.publication.youtube.auth.ClientCredentials;
  import org.opencastproject.publication.youtube.auth.OAuth2CredentialFactory;
  import org.opencastproject.publication.youtube.auth.OAuth2CredentialFactoryImpl;
  import org.opencastproject.util.data.Collections;
  
  import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
  import com.google.api.client.googleapis.media.MediaHttpUploader;
  import com.google.api.client.http.InputStreamContent;
  import com.google.api.client.http.javanet.NetHttpTransport;
  import com.google.api.client.json.jackson2.JacksonFactory;
  import com.google.api.services.youtube.YouTube;
  import com.google.api.services.youtube.YouTubeRequest;
  import com.google.api.services.youtube.model.Playlist;
  import com.google.api.services.youtube.model.PlaylistItem;
  import com.google.api.services.youtube.model.PlaylistItemListResponse;
  import com.google.api.services.youtube.model.PlaylistItemSnippet;
  import com.google.api.services.youtube.model.PlaylistListResponse;
  import com.google.api.services.youtube.model.PlaylistSnippet;
  import com.google.api.services.youtube.model.PlaylistStatus;
  import com.google.api.services.youtube.model.ResourceId;
  import com.google.api.services.youtube.model.SearchListResponse;
  import com.google.api.services.youtube.model.Video;
  import com.google.api.services.youtube.model.VideoListResponse;
  import com.google.api.services.youtube.model.VideoSnippet;
  import com.google.api.services.youtube.model.VideoStatus;
  
  import org.apache.commons.lang3.ArrayUtils;
  
  import java.io.BufferedInputStream;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.util.LinkedList;
  import java.util.List;
  
  public class YouTubeAPIVersion3ServiceImpl implements YouTubeAPIVersion3Service {
  
    private YouTube youTube;
  
    @Override
    public void initialize(final ClientCredentials credentials) throws IOException {
      final OAuth2CredentialFactory factory = new OAuth2CredentialFactoryImpl();
      final GoogleCredential credential = factory.getGoogleCredential(credentials);
      youTube = new YouTube.Builder(new NetHttpTransport(), new JacksonFactory(), credential).build();
    }
  
    @Override
    public Video addVideoToMyChannel(final VideoUpload videoUpload) throws IOException {
      final Video videoObjectDefiningMetadata = new Video();
      final VideoStatus status = new VideoStatus();
      status.setPrivacyStatus(videoUpload.getPrivacyStatus());
      videoObjectDefiningMetadata.setStatus(status);
      // Metadata lives in VideoSnippet
      final VideoSnippet snippet = new VideoSnippet();
      snippet.setTitle(videoUpload.getTitle());
      snippet.setDescription(videoUpload.getDescription());
      final String[] tags = videoUpload.getTags();
      if (ArrayUtils.isNotEmpty(tags)) {
        snippet.setTags(Collections.list(tags));
      }
      // Attach metadata to video object.
      videoObjectDefiningMetadata.setSnippet(snippet);
  
      final File videoFile = videoUpload.getVideoFile();
      final BufferedInputStream inputStream = new BufferedInputStream(new FileInputStream(videoFile));
      final InputStreamContent mediaContent = new InputStreamContent("video/*", inputStream);
      mediaContent.setLength(videoFile.length());
  
      final YouTube.Videos.Insert videoInsert = youTube.videos()
          .insert("snippet,statistics,status", videoObjectDefiningMetadata, mediaContent);
      final MediaHttpUploader uploader = videoInsert.getMediaHttpUploader();
  
      uploader.setDirectUploadEnabled(false);
      uploader.setProgressListener(videoUpload.getProgressListener());
      return execute(videoInsert);
    }
 
   @Override
   public Playlist createPlaylist(final String title, final String description, final String... tags)
           throws IOException {
     final PlaylistSnippet playlistSnippet = new PlaylistSnippet();
     playlistSnippet.setTitle(title);
     playlistSnippet.setDescription(description);
     if (tags.length > 0) {
       playlistSnippet.setTags(Collections.list(tags));
     }
     // Playlists are always public. The videos therein might be private.
     final PlaylistStatus playlistStatus = new PlaylistStatus();
     playlistStatus.setPrivacyStatus("public");
 
     // Create playlist with metadata and status.
     final Playlist youTubePlaylist = new Playlist();
     youTubePlaylist.setSnippet(playlistSnippet);
     youTubePlaylist.setStatus(playlistStatus);
 
     // The first argument tells the API what to return when a successful insert has been executed.
     final YouTube.Playlists.Insert command = youTube.playlists().insert("snippet,status", youTubePlaylist);
     return execute(command);
   }
 
   @Override
   public PlaylistItem addPlaylistItem(final String playlistId, final String videoId) throws IOException {
     // Resource type (video,playlist,channel) needs to be set along with resource id.
     final ResourceId resourceId = new ResourceId();
     resourceId.setKind("youtube#video");
     resourceId.setVideoId(videoId);
 
     // Set the required snippet properties.
     final PlaylistItemSnippet playlistItemSnippet = new PlaylistItemSnippet();
     playlistItemSnippet.setTitle("First video in the test playlist");
     playlistItemSnippet.setPlaylistId(playlistId);
     playlistItemSnippet.setResourceId(resourceId);
 
     // Create the playlist item.
     final PlaylistItem playlistItem = new PlaylistItem();
     playlistItem.setSnippet(playlistItemSnippet);
 
     // The first argument tells the API what to return when a successful insert has been executed.
     final YouTube.PlaylistItems.Insert playlistItemsInsertCommand
         = youTube.playlistItems().insert("snippet,contentDetails", playlistItem);
     return execute(playlistItemsInsertCommand);
   }
 
   @Override
   public void removeVideoFromPlaylist(final String playlistId, final String videoId) throws IOException {
     final PlaylistItem playlistItem = findPlaylistItem(playlistId, videoId);
     final YouTube.PlaylistItems.Delete deleteRequest = youTube.playlistItems().delete(playlistItem.getId());
     execute(deleteRequest);
   }
 
   @Override
   public void removeMyVideo(final String videoId) throws Exception {
     final YouTube.Videos.Delete deleteRequest = youTube.videos().delete(videoId);
     execute(deleteRequest);
   }
 
   @Override
   public void removeMyPlaylist(final String playlistId) throws IOException {
     final YouTube.Playlists.Delete deleteRequest = youTube.playlists().delete(playlistId);
     execute(deleteRequest);
   }
 
   @Override
   public SearchListResponse searchMyVideos(final String queryTerm, final String pageToken, final long maxResults)
           throws IOException {
     final YouTube.Search.List search = youTube.search().list("id,snippet");
     if (pageToken != null) {
       search.set("pageToken", pageToken);
     }
     search.setQ(queryTerm);
     search.setType("video");
     search.setForMine(true);
     search.setMaxResults(maxResults);
     search.setFields("items(id,kind,snippet),nextPageToken,pageInfo,prevPageToken,tokenPagination");
     return execute(search);
   }
 
   @Override
   public Video getVideoById(final String videoId) throws IOException {
     final YouTube.Videos.List search = youTube.videos().list("id,snippet");
     search.setId(videoId);
     search.setFields("items(id,kind,snippet),nextPageToken,pageInfo,prevPageToken,tokenPagination");
     final VideoListResponse response = execute(search);
     return response.getItems().isEmpty() ? null : response.getItems().get(0);
   }
 
   @Override
   public Playlist getMyPlaylistByTitle(final String title) throws IOException {
     final String trimmedTitle = title.trim();
     boolean searchedAllPlaylist = false;
     Playlist playlist = null;
     String nextPageToken = null;
     while (!searchedAllPlaylist) {
       final PlaylistListResponse searchResult = getMyPlaylists(nextPageToken, 50);
       for (final Playlist p : searchResult.getItems()) {
         if (p.getSnippet().getTitle().trim().equals(trimmedTitle)) {
           playlist = p;
           break;
         }
       }
       nextPageToken = searchResult.getNextPageToken();
       searchedAllPlaylist = nextPageToken == null;
     }
     return playlist;
   }
 
   @Override
   public PlaylistListResponse getMyPlaylists(final String pageToken, final long maxResults) throws IOException {
     final YouTube.Playlists.List search = youTube.playlists().list("id,snippet");
     if (pageToken != null) {
       search.set("pageToken", pageToken);
     }
     search.setMaxResults(maxResults);
     search.setMine(true);
     search.setFields("items(id,snippet),kind,nextPageToken,pageInfo,prevPageToken,tokenPagination");
     return execute(search);
   }
 
   @Override
   public PlaylistItemListResponse getPlaylistItems(
       final String playlistId,
       final String pageToken,
       final long maxResults
   ) throws IOException {
     final YouTube.PlaylistItems.List search = youTube.playlistItems().list("id,snippet");
     search.setPlaylistId(playlistId);
     search.setPageToken(pageToken);
     search.setMaxResults(maxResults);
     search.setFields("items(id,kind,snippet),nextPageToken,pageInfo,prevPageToken,tokenPagination");
     return execute(search);
   }
 
   /**
    * @param playlistId may not be {@code null}
    * @param videoId may not be {@code null}
    * @return null when not found.
    * @throws IOException when transaction fails.
    */
   private PlaylistItem findPlaylistItem(final String playlistId, final String videoId) throws IOException {
     final List<PlaylistItem> playlistItems = getAllPlaylistItems(playlistId);
     PlaylistItem playlistItem = null;
     for (final PlaylistItem next : playlistItems) {
       final String id = next.getSnippet().getResourceId().getVideoId();
       if (videoId.equals(id)) {
         playlistItem = next;
         break;
       }
     }
     return playlistItem;
   }
 
   /**
    *
    * @param playlistId may not be {@code null}
    * @return zero or more playlist items.
    * @throws IOException  when transaction fails.
    */
   private List<PlaylistItem> getAllPlaylistItems(final String playlistId) throws IOException {
     final List<PlaylistItem> playlistItems = new LinkedList<PlaylistItem>();
     boolean done = false;
     String nextPageToken = null;
     while (!done) {
       final PlaylistItemListResponse searchResult = getPlaylistItems(playlistId, nextPageToken, 50);
       playlistItems.addAll(searchResult.getItems());
       nextPageToken = searchResult.getNextPageToken();
       done = nextPageToken == null;
     }
     return playlistItems;
   }
 
   /**
    * @see com.google.api.services.youtube.YouTubeRequest#execute()
    * @param command may not be {@code null}
    * @param <T> type of request.
    * @return result; may be {@code null}
    * @throws IOException  when transaction fails.
    */
   private <T> T execute(final YouTubeRequest<T> command) throws IOException {
     return command.execute();
   }
 }