content: /*
   * Copyright (C) 2019 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.analytics;
  
  import androidx.annotation.Nullable;
  import com.google.android.exoplayer2.Player.DiscontinuityReason;
  import com.google.android.exoplayer2.Timeline;
  import com.google.android.exoplayer2.analytics.AnalyticsListener.EventTime;
  import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
  
  /**
   * Manager for active playback sessions.
   *
   * <p>The manager keeps track of the association between window index and/or media period id to
   * session identifier.
   */
  public interface PlaybackSessionManager {
  
    /** A listener for session updates. */
    interface Listener {
  
      /**
       * Called when a new session is created as a result of {@link #updateSessions(EventTime)}.
       *
       * @param eventTime The {@link EventTime} at which the session is created.
       * @param sessionId The identifier of the new session.
       */
      void onSessionCreated(EventTime eventTime, String sessionId);
  
      /**
       * Called when a session becomes active, i.e. playing in the foreground.
       *
       * @param eventTime The {@link EventTime} at which the session becomes active.
       * @param sessionId The identifier of the session.
       */
      void onSessionActive(EventTime eventTime, String sessionId);
  
      /**
       * Called when a session is interrupted by ad playback.
       *
       * @param eventTime The {@link EventTime} at which the ad playback starts.
       * @param contentSessionId The session identifier of the content session.
       * @param adSessionId The identifier of the ad session.
       */
      void onAdPlaybackStarted(EventTime eventTime, String contentSessionId, String adSessionId);
  
      /**
       * Called when a session is permanently finished.
       *
       * @param eventTime The {@link EventTime} at which the session finished.
       * @param sessionId The identifier of the finished session.
       * @param automaticTransitionToNextPlayback Whether the session finished because of an automatic
       *     transition to the next playback item.
       */
      void onSessionFinished(
          EventTime eventTime, String sessionId, boolean automaticTransitionToNextPlayback);
    }
  
    /**
     * Sets the listener to be notified of session updates. Must be called before the session manager
     * is used.
     *
     * @param listener The {@link Listener} to be notified of session updates.
     */
    void setListener(Listener listener);
  
    /**
     * Returns the session identifier for the given media period id.
     *
     * <p>Note that this will reserve a new session identifier if it doesn't exist yet, but will not
     * call any {@link Listener} callbacks.
     *
     * @param timeline The timeline, {@code mediaPeriodId} is part of.
     * @param mediaPeriodId A {@link MediaPeriodId}.
     */
    String getSessionForMediaPeriodId(Timeline timeline, MediaPeriodId mediaPeriodId);
  
    /**
     * Returns whether an event time belong to a session.
     *
     * @param eventTime The {@link EventTime}.
     * @param sessionId A session identifier.
     * @return Whether the event belongs to the specified session.
     */
    boolean belongsToSession(EventTime eventTime, String sessionId);
  
    /**
     * Updates or creates sessions based on a player {@link EventTime}.
     *
     * <p>Call {@link #updateSessionsWithTimelineChange(EventTime)} or {@link
     * #updateSessionsWithDiscontinuity(EventTime, int)} if the event is a {@link Timeline} change or
     * a position discontinuity respectively.
     *
     * @param eventTime The {@link EventTime}.
     */
    void updateSessions(EventTime eventTime);
  
    /**
     * Updates or creates sessions based on a {@link Timeline} change at {@link EventTime}.
     *
     * <p>Should be called instead of {@link #updateSessions(EventTime)} if a {@link Timeline} change
     * occurred.
     *
     * @param eventTime The {@link EventTime} with the timeline change.
     */
    void updateSessionsWithTimelineChange(EventTime eventTime);
  
    /**
     * Updates or creates sessions based on a position discontinuity at {@link EventTime}.
     *
     * <p>Should be called instead of {@link #updateSessions(EventTime)} if a position discontinuity
     * occurred.
     *
     * @param eventTime The {@link EventTime} of the position discontinuity.
     * @param reason The {@link DiscontinuityReason}.
     */
    void updateSessionsWithDiscontinuity(EventTime eventTime, @DiscontinuityReason int reason);
  
    /**
     * Returns the session identifier of the session that is currently actively playing, or {@code
     * null} if there no such session.
     */
    @Nullable
    String getActiveSessionId();
  
    /**
     * Finishes all existing sessions and calls their respective {@link
     * Listener#onSessionFinished(EventTime, String, boolean)} callback.
     *
     * @param eventTime The event time at which sessions are finished.
     */
    void finishAllSessions(EventTime eventTime);
  }
  