content: /*
   * Copyright (C) 2018 The Android Open Source Project
   *
   * Licensed under the Apache 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://www.apache.org/licenses/LICENSE-2.0
   *
   * 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 com.google.android.exoplayer2.ext.cast;
  
  import static com.google.android.exoplayer2.ext.cast.CastTimeline.ItemData.UNKNOWN_CONTENT_ID;
  import static com.google.android.exoplayer2.util.Assertions.checkNotNull;
  import static com.google.android.exoplayer2.util.Assertions.checkStateNotNull;
  
  import android.util.SparseArray;
  import androidx.annotation.Nullable;
  import androidx.annotation.VisibleForTesting;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.MediaItem;
  import com.google.android.exoplayer2.Player;
  import com.google.android.gms.cast.MediaInfo;
  import com.google.android.gms.cast.MediaQueueItem;
  import com.google.android.gms.cast.MediaStatus;
  import com.google.android.gms.cast.framework.media.RemoteMediaClient;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  
  /**
   * Creates {@link CastTimeline CastTimelines} from cast receiver app status updates.
   *
   * <p>This class keeps track of the duration reported by the current item to fill any missing
   * durations in the media queue items [See internal: b/65152553].
   */
  /* package */ final class CastTimelineTracker {
  
    private final SparseArray<CastTimeline.ItemData> itemIdToData;
    private final MediaItemConverter mediaItemConverter;
    @VisibleForTesting /* package */ final HashMap<String, MediaItem> mediaItemsByContentId;
  
    /**
     * Creates an instance.
     *
     * @param mediaItemConverter The converter used to convert from a {@link MediaQueueItem} to a
     *     {@link MediaItem}.
     */
    public CastTimelineTracker(MediaItemConverter mediaItemConverter) {
      this.mediaItemConverter = mediaItemConverter;
      itemIdToData = new SparseArray<>();
      mediaItemsByContentId = new HashMap<>();
    }
  
    /**
     * Called when media items {@linkplain Player#setMediaItems have been set to the playlist} and are
     * sent to the cast playback queue. A future queue update of the {@link RemoteMediaClient} will
     * reflect this addition.
     *
     * @param mediaItems The media items that have been set.
     * @param mediaQueueItems The corresponding media queue items.
     */
    public void onMediaItemsSet(List<MediaItem> mediaItems, MediaQueueItem[] mediaQueueItems) {
      mediaItemsByContentId.clear();
      onMediaItemsAdded(mediaItems, mediaQueueItems);
    }
  
    /**
     * Called when media items {@linkplain Player#addMediaItems(List) have been added} and are sent to
     * the cast playback queue. A future queue update of the {@link RemoteMediaClient} will reflect
     * this addition.
     *
     * @param mediaItems The media items that have been added.
     * @param mediaQueueItems The corresponding media queue items.
     */
    public void onMediaItemsAdded(List<MediaItem> mediaItems, MediaQueueItem[] mediaQueueItems) {
      for (int i = 0; i < mediaItems.size(); i++) {
        mediaItemsByContentId.put(
            checkNotNull(mediaQueueItems[i].getMedia()).getContentId(), mediaItems.get(i));
      }
    }
  
    /**
     * Returns a {@link CastTimeline} that represents the state of the given {@code
     * remoteMediaClient}.
     *
     * <p>Returned timelines may contain values obtained from {@code remoteMediaClient} in previous
     * invocations of this method.
     *
     * @param remoteMediaClient The Cast media client.
     * @return A {@link CastTimeline} that represents the given {@code remoteMediaClient} status.
     */
    public CastTimeline getCastTimeline(RemoteMediaClient remoteMediaClient) {
      int[] itemIds = remoteMediaClient.getMediaQueue().getItemIds();
      if (itemIds.length > 0) {
        // Only remove unused items when there is something in the queue to avoid removing all entries
        // if the remote media client clears the queue temporarily. See [Internal ref: b/128825216].
        removeUnusedItemDataEntries(itemIds);
      }
  
      // TODO: Reset state when the app instance changes [Internal ref: b/129672468].
      MediaStatus mediaStatus = remoteMediaClient.getMediaStatus();
      if (mediaStatus == null) {
        return CastTimeline.EMPTY_CAST_TIMELINE;
      }
  
      int currentItemId = mediaStatus.getCurrentItemId();
      String currentContentId = checkStateNotNull(mediaStatus.getMediaInfo()).getContentId();
      MediaItem mediaItem = mediaItemsByContentId.get(currentContentId);
      updateItemData(
          currentItemId,
          mediaItem != null ? mediaItem : MediaItem.EMPTY,
          mediaStatus.getMediaInfo(),
          currentContentId,
          /* defaultPositionUs= */ C.TIME_UNSET);
  
      for (MediaQueueItem queueItem : mediaStatus.getQueueItems()) {
        long defaultPositionUs = (long) (queueItem.getStartTime() * C.MICROS_PER_SECOND);
        @Nullable MediaInfo mediaInfo = queueItem.getMedia();
        String contentId = mediaInfo != null ? mediaInfo.getContentId() : UNKNOWN_CONTENT_ID;
        mediaItem = mediaItemsByContentId.get(contentId);
        updateItemData(
            queueItem.getItemId(),
            mediaItem != null ? mediaItem : mediaItemConverter.toMediaItem(queueItem),
            mediaInfo,
            contentId,
            defaultPositionUs);
      }
      return new CastTimeline(itemIds, itemIdToData);
    }
  
    private void updateItemData(
        int itemId,
        MediaItem mediaItem,
        @Nullable MediaInfo mediaInfo,
        String contentId,
        long defaultPositionUs) {
      CastTimeline.ItemData previousData = itemIdToData.get(itemId, CastTimeline.ItemData.EMPTY);
      long durationUs = CastUtils.getStreamDurationUs(mediaInfo);
      if (durationUs == C.TIME_UNSET) {
        durationUs = previousData.durationUs;
      }
      boolean isLive =
          mediaInfo == null
              ? previousData.isLive
              : mediaInfo.getStreamType() == MediaInfo.STREAM_TYPE_LIVE;
      if (defaultPositionUs == C.TIME_UNSET) {
        defaultPositionUs = previousData.defaultPositionUs;
      }
      itemIdToData.put(
          itemId,
          previousData.copyWithNewValues(
              durationUs, defaultPositionUs, isLive, mediaItem, contentId));
    }
  
    private void removeUnusedItemDataEntries(int[] itemIds) {
      HashSet<Integer> scratchItemIds = new HashSet<>(/* initialCapacity= */ itemIds.length * 2);
      for (int id : itemIds) {
        scratchItemIds.add(id);
      }
  
      int index = 0;
      while (index < itemIdToData.size()) {
        if (!scratchItemIds.contains(itemIdToData.keyAt(index))) {
          CastTimeline.ItemData itemData = itemIdToData.valueAt(index);
          mediaItemsByContentId.remove(itemData.contentId);
          itemIdToData.removeAt(index);
        } else {
          index++;
        }
      }
    }
  }
  