import ClientMetricReport from '../clientmetricreport/ClientMetricReport';
import ServerSideNetworkAdaption from '../signalingclient/ServerSideNetworkAdaption';
import VideoStreamIdSet from '../videostreamidset/VideoStreamIdSet';
import VideoStreamIndex from '../videostreamindex/VideoStreamIndex';
import VideoTileController from '../videotilecontroller/VideoTileController';
import VideoDownlinkObserver from './VideoDownlinkObserver';
import VideoPreferences from './VideoPreferences';
/**
 * [[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. This value will be truncated
     * to the maximum subscription limit of the call.
     *
     * When a policy is passed into a meeting session, this will be called
     * once every second 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) Call and observer function on all added `VideoDownlinkObserver`. Can be used to notify observers
     * of video tile pauses.
     */
    forEachObserver?(observerFunc: (observer: VideoDownlinkObserver) => void): void;
    /**
     * (Optional) Add observer that allows policy to immediately request an update based off current choices. Only
     * one observer can be set at a time.
     */
    setWantsResubscribeObserver?(observer: () => void): 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;
    /**
     * Additional server side features to be enabled for network adaption. Policy implementations
     * must abide by the restrictions in the returned `ServerSideNetworkAdaption` enum value.
     */
    getServerSideNetworkAdaption?(): ServerSideNetworkAdaption;
    /**
     * Dynamically switch any client behavior to the adaption type which this policy indicated support
     * to from `supportedServerSideNetworkAdaptions`.
     */
    setServerSideNetworkAdaption?(adaption: ServerSideNetworkAdaption): void;
    /**
     * Values which this policy supports being overriden to. The server may use this to transition
     * clients to different values of `ServerSideNetworkAdaption`. Override this function
     * to return an empty list to disable any server override attempts.
     */
    supportedServerSideNetworkAdaptions?(): ServerSideNetworkAdaption[];
    /**
     * Used in combination of `getServerSideNetworkAdaption` and `wantsResubscribe`
     * to indicate any added, updated, or removed video preferences.
     */
    getVideoPreferences?(): VideoPreferences;
    /**
     * Used to indicate that this policy can handle the increased complexity
     * required to deal with layers of different frame rates (i.e. balances
     * tradeoffs of resolution vs. frame rate, will not degrade resolution or
     * framerate during recovery, etc.)
     */
    wantsAllTemporalLayersInIndex?(): boolean;
}