/*
 * Copyright (C) 2017 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 org.mozilla.thirdparty.com.google.android.exoplayer2;

import androidx.annotation.CheckResult;
import androidx.annotation.Nullable;
import org.mozilla.thirdparty.com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
import org.mozilla.thirdparty.com.google.android.exoplayer2.source.TrackGroupArray;
import org.mozilla.thirdparty.com.google.android.exoplayer2.trackselection.TrackSelectorResult;

/**
 * Information about an ongoing playback.
 */
/* package */ final class PlaybackInfo {

  /**
   * Dummy media period id used while the timeline is empty and no period id is specified. This id
   * is used when playback infos are created with {@link #createDummy(long, TrackSelectorResult)}.
   */
  private static final MediaPeriodId DUMMY_MEDIA_PERIOD_ID =
      new MediaPeriodId(/* periodUid= */ new Object());

  /** The current {@link Timeline}. */
  public final Timeline timeline;
  /** The {@link MediaPeriodId} of the currently playing media period in the {@link #timeline}. */
  public final MediaPeriodId periodId;
  /**
   * The start position at which playback started in {@link #periodId} relative to the start of the
   * associated period in the {@link #timeline}, in microseconds. Note that this value changes for
   * each position discontinuity.
   */
  public final long startPositionUs;
  /**
   * If {@link #periodId} refers to an ad, the position of the suspended content relative to the
   * start of the associated period in the {@link #timeline}, in microseconds. {@link C#TIME_UNSET}
   * if {@link #periodId} does not refer to an ad or if the suspended content should be played from
   * its default position.
   */
  public final long contentPositionUs;
  /** The current playback state. One of the {@link Player}.STATE_ constants. */
  @Player.State public final int playbackState;
  /** The current playback error, or null if this is not an error state. */
  @Nullable public final ExoPlaybackException playbackError;
  /** Whether the player is currently loading. */
  public final boolean isLoading;
  /** The currently available track groups. */
  public final TrackGroupArray trackGroups;
  /** The result of the current track selection. */
  public final TrackSelectorResult trackSelectorResult;
  /** The {@link MediaPeriodId} of the currently loading media period in the {@link #timeline}. */
  public final MediaPeriodId loadingMediaPeriodId;

  /**
   * Position up to which media is buffered in {@link #loadingMediaPeriodId) relative to the start
   * of the associated period in the {@link #timeline}, in microseconds.
   */
  public volatile long bufferedPositionUs;
  /**
   * Total duration of buffered media from {@link #positionUs} to {@link #bufferedPositionUs}
   * including all ads.
   */
  public volatile long totalBufferedDurationUs;
  /**
   * Current playback position in {@link #periodId} relative to the start of the associated period
   * in the {@link #timeline}, in microseconds.
   */
  public volatile long positionUs;

  /**
   * Creates empty dummy playback info which can be used for masking as long as no real playback
   * info is available.
   *
   * @param startPositionUs The start position at which playback should start, in microseconds.
   * @param emptyTrackSelectorResult An empty track selector result with null entries for each
   *     renderer.
   * @return A dummy playback info.
   */
  public static PlaybackInfo createDummy(
      long startPositionUs, TrackSelectorResult emptyTrackSelectorResult) {
    return new PlaybackInfo(
        Timeline.EMPTY,
        DUMMY_MEDIA_PERIOD_ID,
        startPositionUs,
        /* contentPositionUs= */ C.TIME_UNSET,
        Player.STATE_IDLE,
        /* playbackError= */ null,
        /* isLoading= */ false,
        TrackGroupArray.EMPTY,
        emptyTrackSelectorResult,
        DUMMY_MEDIA_PERIOD_ID,
        startPositionUs,
        /* totalBufferedDurationUs= */ 0,
        startPositionUs);
  }

  /**
   * Create playback info.
   *
   * @param timeline See {@link #timeline}.
   * @param periodId See {@link #periodId}.
   * @param startPositionUs See {@link #startPositionUs}.
   * @param contentPositionUs See {@link #contentPositionUs}.
   * @param playbackState See {@link #playbackState}.
   * @param isLoading See {@link #isLoading}.
   * @param trackGroups See {@link #trackGroups}.
   * @param trackSelectorResult See {@link #trackSelectorResult}.
   * @param loadingMediaPeriodId See {@link #loadingMediaPeriodId}.
   * @param bufferedPositionUs See {@link #bufferedPositionUs}.
   * @param totalBufferedDurationUs See {@link #totalBufferedDurationUs}.
   * @param positionUs See {@link #positionUs}.
   */
  public PlaybackInfo(
      Timeline timeline,
      MediaPeriodId periodId,
      long startPositionUs,
      long contentPositionUs,
      @Player.State int playbackState,
      @Nullable ExoPlaybackException playbackError,
      boolean isLoading,
      TrackGroupArray trackGroups,
      TrackSelectorResult trackSelectorResult,
      MediaPeriodId loadingMediaPeriodId,
      long bufferedPositionUs,
      long totalBufferedDurationUs,
      long positionUs) {
    this.timeline = timeline;
    this.periodId = periodId;
    this.startPositionUs = startPositionUs;
    this.contentPositionUs = contentPositionUs;
    this.playbackState = playbackState;
    this.playbackError = playbackError;
    this.isLoading = isLoading;
    this.trackGroups = trackGroups;
    this.trackSelectorResult = trackSelectorResult;
    this.loadingMediaPeriodId = loadingMediaPeriodId;
    this.bufferedPositionUs = bufferedPositionUs;
    this.totalBufferedDurationUs = totalBufferedDurationUs;
    this.positionUs = positionUs;
  }

  /**
   * Returns dummy media period id for the first-to-be-played period of the current timeline.
   *
   * @param shuffleModeEnabled Whether shuffle mode is enabled.
   * @param window A writable {@link Timeline.Window}.
   * @param period A writable {@link Timeline.Period}.
   * @return A dummy media period id for the first-to-be-played period of the current timeline.
   */
  public MediaPeriodId getDummyFirstMediaPeriodId(
      boolean shuffleModeEnabled, Timeline.Window window, Timeline.Period period) {
    if (timeline.isEmpty()) {
      return DUMMY_MEDIA_PERIOD_ID;
    }
    int firstWindowIndex = timeline.getFirstWindowIndex(shuffleModeEnabled);
    int firstPeriodIndex = timeline.getWindow(firstWindowIndex, window).firstPeriodIndex;
    int currentPeriodIndex = timeline.getIndexOfPeriod(periodId.periodUid);
    long windowSequenceNumber = C.INDEX_UNSET;
    if (currentPeriodIndex != C.INDEX_UNSET) {
      int currentWindowIndex = timeline.getPeriod(currentPeriodIndex, period).windowIndex;
      if (firstWindowIndex == currentWindowIndex) {
        // Keep window sequence number if the new position is still in the same window.
        windowSequenceNumber = periodId.windowSequenceNumber;
      }
    }
    return new MediaPeriodId(timeline.getUidOfPeriod(firstPeriodIndex), windowSequenceNumber);
  }

  /**
   * Copies playback info with new playing position.
   *
   * @param periodId New playing media period. See {@link #periodId}.
   * @param positionUs New position. See {@link #positionUs}.
   * @param contentPositionUs New content position. See {@link #contentPositionUs}. Value is ignored
   *     if {@code periodId.isAd()} is true.
   * @param totalBufferedDurationUs New buffered duration. See {@link #totalBufferedDurationUs}.
   * @return Copied playback info with new playing position.
   */
  @CheckResult
  public PlaybackInfo copyWithNewPosition(
      MediaPeriodId periodId,
      long positionUs,
      long contentPositionUs,
      long totalBufferedDurationUs) {
    return new PlaybackInfo(
        timeline,
        periodId,
        positionUs,
        periodId.isAd() ? contentPositionUs : C.TIME_UNSET,
        playbackState,
        playbackError,
        isLoading,
        trackGroups,
        trackSelectorResult,
        loadingMediaPeriodId,
        bufferedPositionUs,
        totalBufferedDurationUs,
        positionUs);
  }

  /**
   * Copies playback info with the new timeline.
   *
   * @param timeline New timeline. See {@link #timeline}.
   * @return Copied playback info with the new timeline.
   */
  @CheckResult
  public PlaybackInfo copyWithTimeline(Timeline timeline) {
    return new PlaybackInfo(
        timeline,
        periodId,
        startPositionUs,
        contentPositionUs,
        playbackState,
        playbackError,
        isLoading,
        trackGroups,
        trackSelectorResult,
        loadingMediaPeriodId,
        bufferedPositionUs,
        totalBufferedDurationUs,
        positionUs);
  }

  /**
   * Copies playback info with new playback state.
   *
   * @param playbackState New playback state. See {@link #playbackState}.
   * @return Copied playback info with new playback state.
   */
  @CheckResult
  public PlaybackInfo copyWithPlaybackState(int playbackState) {
    return new PlaybackInfo(
        timeline,
        periodId,
        startPositionUs,
        contentPositionUs,
        playbackState,
        playbackError,
        isLoading,
        trackGroups,
        trackSelectorResult,
        loadingMediaPeriodId,
        bufferedPositionUs,
        totalBufferedDurationUs,
        positionUs);
  }

  /**
   * Copies playback info with a playback error.
   *
   * @param playbackError The error. See {@link #playbackError}.
   * @return Copied playback info with the playback error.
   */
  @CheckResult
  public PlaybackInfo copyWithPlaybackError(@Nullable ExoPlaybackException playbackError) {
    return new PlaybackInfo(
        timeline,
        periodId,
        startPositionUs,
        contentPositionUs,
        playbackState,
        playbackError,
        isLoading,
        trackGroups,
        trackSelectorResult,
        loadingMediaPeriodId,
        bufferedPositionUs,
        totalBufferedDurationUs,
        positionUs);
  }

  /**
   * Copies playback info with new loading state.
   *
   * @param isLoading New loading state. See {@link #isLoading}.
   * @return Copied playback info with new loading state.
   */
  @CheckResult
  public PlaybackInfo copyWithIsLoading(boolean isLoading) {
    return new PlaybackInfo(
        timeline,
        periodId,
        startPositionUs,
        contentPositionUs,
        playbackState,
        playbackError,
        isLoading,
        trackGroups,
        trackSelectorResult,
        loadingMediaPeriodId,
        bufferedPositionUs,
        totalBufferedDurationUs,
        positionUs);
  }

  /**
   * Copies playback info with new track information.
   *
   * @param trackGroups New track groups. See {@link #trackGroups}.
   * @param trackSelectorResult New track selector result. See {@link #trackSelectorResult}.
   * @return Copied playback info with new track information.
   */
  @CheckResult
  public PlaybackInfo copyWithTrackInfo(
      TrackGroupArray trackGroups, TrackSelectorResult trackSelectorResult) {
    return new PlaybackInfo(
        timeline,
        periodId,
        startPositionUs,
        contentPositionUs,
        playbackState,
        playbackError,
        isLoading,
        trackGroups,
        trackSelectorResult,
        loadingMediaPeriodId,
        bufferedPositionUs,
        totalBufferedDurationUs,
        positionUs);
  }

  /**
   * Copies playback info with new loading media period.
   *
   * @param loadingMediaPeriodId New loading media period id. See {@link #loadingMediaPeriodId}.
   * @return Copied playback info with new loading media period.
   */
  @CheckResult
  public PlaybackInfo copyWithLoadingMediaPeriodId(MediaPeriodId loadingMediaPeriodId) {
    return new PlaybackInfo(
        timeline,
        periodId,
        startPositionUs,
        contentPositionUs,
        playbackState,
        playbackError,
        isLoading,
        trackGroups,
        trackSelectorResult,
        loadingMediaPeriodId,
        bufferedPositionUs,
        totalBufferedDurationUs,
        positionUs);
  }
}