// In general, these types are only available behind a command line flag or an origin trial in
// Chrome 90+.

// This API depends on WebCodecs.
/// <reference types="dom-webcodecs" />

// Versioning:
// Until the above-mentioned spec is finalized, the major version number is 0. Although not
// necessary for version 0, consider incrementing the minor version number for breaking changes.

// The following modify existing DOM types to allow defining type-safe APIs on audio and video tracks.

/** Specialize MediaStreamTrack so that we can refer specifically to an audio track. */
interface MediaStreamAudioTrack extends MediaStreamTrack {
    readonly kind: "audio";
    clone(): MediaStreamAudioTrack;
}

/** Specialize MediaStreamTrack so that we can refer specifically to a video track. */
interface MediaStreamVideoTrack extends MediaStreamTrack {
    readonly kind: "video";
    clone(): MediaStreamVideoTrack;
}

/** Assert that getAudioTracks and getVideoTracks return the tracks with the appropriate kind. */
interface MediaStream {
    getAudioTracks(): MediaStreamAudioTrack[];
    getVideoTracks(): MediaStreamVideoTrack[];
}

// The following were originally generated from the spec using
// https://github.com/microsoft/TypeScript-DOM-lib-generator, then heavily modified.

/**
 * A track sink that is capable of exposing the unencoded frames from the track to a
 * ReadableStream, and exposes a control channel for signals going in the oppposite direction.
 */
interface MediaStreamTrackProcessor<T extends AudioData | VideoFrame> {
    /**
     * Allows reading the frames flowing through the MediaStreamTrack provided to the constructor.
     */
    readonly readable: ReadableStream<T>;
    /** Allows sending control signals to the MediaStreamTrack provided to the constructor. */
    readonly writableControl: WritableStream<MediaStreamTrackSignal>;
}

declare var MediaStreamTrackProcessor: {
    prototype: MediaStreamTrackProcessor<any>;

    /** Constructor overrides based on the type of track. */
    new(init: MediaStreamTrackProcessorInit & { track: MediaStreamAudioTrack }): MediaStreamTrackProcessor<AudioData>;
    new(init: MediaStreamTrackProcessorInit & { track: MediaStreamVideoTrack }): MediaStreamTrackProcessor<VideoFrame>;
};

interface MediaStreamTrackProcessorInit {
    track: MediaStreamTrack;
    /**
     * If media frames are not read from MediaStreamTrackProcessor.readable quickly enough, the
     * MediaStreamTrackProcessor will internally buffer up to maxBufferSize of the frames produced
     * by the track. If the internal buffer is full, each time the track produces a new frame, the
     * oldest frame in the buffer will be dropped and the new frame will be added to the buffer.
     */
    maxBufferSize?: number | undefined;
}

/**
 * Takes video frames as input, and emits control signals that result from subsequent processing.
 */
interface MediaStreamTrackGenerator<T extends AudioData | VideoFrame> extends MediaStreamTrack {
    /**
     * Allows writing media frames to the MediaStreamTrackGenerator, which is itself a
     * MediaStreamTrack. When a frame is written to writable, the frame’s close() method is
     * automatically invoked, so that its internal resources are no longer accessible from
     * JavaScript.
     */
    readonly writable: WritableStream<T>;
    /**
     * Allows reading control signals sent from any sinks connected to the
     * MediaStreamTrackGenerator.
     */
    readonly readableControl: ReadableStream<MediaStreamTrackSignal>;
}

type MediaStreamAudioTrackGenerator = MediaStreamTrackGenerator<AudioData> & MediaStreamAudioTrack;
type MediaStreamVideoTrackGenerator = MediaStreamTrackGenerator<VideoFrame> & MediaStreamVideoTrack;

declare var MediaStreamTrackGenerator: {
    prototype: MediaStreamTrackGenerator<any>;

    /** Constructor overrides based on the type of track. */
    new(
        init: MediaStreamTrackGeneratorInit & { kind: "audio"; signalTarget?: MediaStreamAudioTrack | undefined },
    ): MediaStreamAudioTrackGenerator;
    new(
        init: MediaStreamTrackGeneratorInit & { kind: "video"; signalTarget?: MediaStreamVideoTrack | undefined },
    ): MediaStreamVideoTrackGenerator;
};

interface MediaStreamTrackGeneratorInit {
    kind: MediaStreamTrackGeneratorKind;
    /**
     * (Optional) track to which the MediaStreamTrackGenerator will automatically forward control
     * signals. If signalTarget is provided and signalTarget.kind and kind do not match, the
     * MediaStreamTrackGenerator’s constructor will raise an exception.
     */
    signalTarget?: MediaStreamTrack | undefined;
}

type MediaStreamTrackGeneratorKind = "audio" | "video";

type MediaStreamTrackSignalType = "request-frame";

interface MediaStreamTrackSignal {
    signalType: MediaStreamTrackSignalType;
}