import ClientMetricReport from '../clientmetricreport/ClientMetricReport';
import VideoStreamIdSet from '../videostreamidset/VideoStreamIdSet';
import VideoStreamIndex from '../videostreamindex/VideoStreamIndex';
import VideoTileController from '../videotilecontroller/VideoTileController';
import VideoDownlinkObserver from './VideoDownlinkObserver';
/**
 * [[VideoDownlinkBandwidthPolicy]] makes decisions about downlink
 * video bandwidth usage.
 */
export default interface VideoDownlinkBandwidthPolicy {
    /**
     * Reset back to initial state
     */
    reset(): void;
    /**
     * Potentially update the desired set of video streams to receive
     * based on the given [[VideoStreamIndex]].
     */
    updateIndex(videoIndex: VideoStreamIndex): void;
    /**
     * Update connection metrics
     */
    updateMetrics(clientMetricReport: ClientMetricReport): void;
    /**
     * Returns true if the policy has decided that a change to subscribed
     * set of video streams to receive would be beneficial.
     */
    wantsResubscribe(): boolean;
    /**
     * Updates the internal state with the set of streams we expect to be
     * subscribed to, and return the set.
     *
     * When a policy is passed into a meeting session, this will be called
     * once every two seconds to check if the subscriptions have changed.
     */
    chooseSubscriptions(): VideoStreamIdSet;
    /**
     * (Optional) Add VideoDownlinkObserver to observer resubscribe requests
     */
    addObserver?(observer: VideoDownlinkObserver): void;
    /**
     * (Optional) Removes the VideoDownlinkObserver.
     */
    removeObserver?(observer: VideoDownlinkObserver): void;
    /**
     * (Optional) Bind the video tile controller to the policy to allow it to control the video tiles such as pause
     * and unpause.
     * The audio video controller should call this method to pass down a transceiver controller to the policy
     * when the meeting starts and set it to undefined when the meeting ends.
     * @param tileController the video tile controller
     */
    bindToTileController?(tileController: VideoTileController | undefined): void;
}