element-call-Github/src/state/CallViewModel/remoteMembers/ConnectionFactory.ts

/*
Copyright 2025 Element Creations Ltd.

SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
Please see LICENSE in the repository root for full details.
*/

import {
  Room as LivekitRoom,
  type RoomOptions,
  type BaseKeyProvider,
  type E2EEManagerOptions,
  type BaseE2EEManager,
} from "livekit-client";
import { logger, type Logger } from "matrix-js-sdk/lib/logger";
// imported as inline to support worker when loaded from a cdn (cross domain)
import E2EEWorker from "livekit-client/e2ee-worker?worker&inline";
import { type CallMembershipIdentityParts } from "matrix-js-sdk/lib/matrixrtc/EncryptionManager";
import { type UnstableLivekitTransport } from "matrix-js-sdk/lib/matrixrtc";

import { type ObservableScope } from "../../ObservableScope.ts";
import { Connection } from "./Connection.ts";
import type { MediaDevices } from "../../MediaDevices.ts";
import type { Behavior } from "../../Behavior.ts";
import type { ProcessorState } from "../../../livekit/TrackProcessorContext.tsx";
import { getLiveKitOptions } from "../../../livekit/options.ts";
import {
  advancedCamera,
  cameraResolution,
  cameraFramerate,
  cameraBitrate,
  cameraCodec,
  parseResolution,
  echoCancellationSetting,
  noiseSuppressionSetting,
  autoGainControlSetting,
} from "../../../settings/settings.ts";
import { type ClientOpenIDParts } from "../../../livekit/auth";

// TODO evaluate if this should be done like the Publisher Factory
export interface ConnectionFactory {
  createConnection(
    scope: ObservableScope,
    role: "publisher" | "subscriber",
    transport: UnstableLivekitTransport,
    serverName: string,
    ownMembershipIdentity: CallMembershipIdentityParts,
    logger: Logger,
  ): Connection;
}

export class ECConnectionFactory implements ConnectionFactory {
  private readonly livekitRoomFactory: () => LivekitRoom;

  /**
   * Creates a ConnectionFactory for LiveKit connections.
   *
   * @param client - The OpenID client parts for authentication, needed to get openID and JWT tokens.
   * @param roomId - The ID of the Matrix room in which the session takes place.
   * @param slotId - The ID of the MatrixRTC slot in which the session takes place.
   * @param devices - Used for video/audio out/in capture options.
   * @param processorState$ - Effects like background blur (only for publishing connection?)
   * @param livekitKeyProvider - Optional key provider for end-to-end encryption.
   * @param controlledAudioDevices - Option to indicate whether audio output device is controlled externally (native mobile app).
   * @param livekitRoomFactory - Optional factory function (for testing) to create LivekitRoom instances. If not provided, a default factory is used.
   */
  public constructor(
    private client: ClientOpenIDParts,
    private readonly roomId: string,
    private readonly slotId: string,
    private devices: MediaDevices,
    private processorState$: Behavior<ProcessorState>,
    livekitKeyProvider: BaseKeyProvider | undefined,
    private controlledAudioDevices: boolean,
    livekitRoomFactory?: () => LivekitRoom,
  ) {
    const defaultFactory = (): LivekitRoom => {
      const roomOptions = generateRoomOption({
        devices: this.devices,
        processorState: this.processorState$.value,
        e2eeLivekitOptions: livekitKeyProvider && {
          keyProvider: livekitKeyProvider,
          // It's important that every room use a separate E2EE worker.
          // They get confused if given streams from multiple rooms.
          worker: new E2EEWorker(),
        },
        controlledAudioDevices: this.controlledAudioDevices,
      });
      logger.info("[ECConnectionFactory] livekit room options: ", roomOptions);
      return new LivekitRoom(roomOptions);
    };
    this.livekitRoomFactory = livekitRoomFactory ?? defaultFactory;
  }

  /**
   *
   * @param scope The observable scope (used for clean-up)
   * @param transport The transport to use for this connection.
   * @param serverName The name of the homeserver to which the {@link transport} belongs.
   * @param ownMembershipIdentity required to connect (using the jwt service) with the SFU.
   * @param logger The logger instance to use for this connection.
   * @param sfuConfig optional config in case we already have a token for this connection.
   * @returns
   */
  public createConnection(
    scope: ObservableScope,
    role: "publisher" | "subscriber",
    transport: UnstableLivekitTransport,
    serverName: string,
    ownMembershipIdentity: CallMembershipIdentityParts,
    logger: Logger,
  ): Connection {
    return new Connection(
      {
        roomId: this.roomId,
        slotId: this.slotId,
        role,
        transport,
        serverName,
        client: this.client,
        scope: scope,
        livekitRoomFactory: this.livekitRoomFactory,
        ownMembershipIdentity,
      },
      logger,
    );
  }
}

/**
 *  Generate the initial LiveKit RoomOptions based on the current media devices and processor state.
 *  Reads audio processing and camera quality settings directly from Settings.
 */
function generateRoomOption({
  devices,
  processorState,
  e2eeLivekitOptions,
  controlledAudioDevices,
}: {
  devices: MediaDevices;
  processorState: ProcessorState;
  e2eeLivekitOptions:
    | E2EEManagerOptions
    | { e2eeManager: BaseE2EEManager }
    | undefined;
  controlledAudioDevices: boolean;
}): RoomOptions {
  const liveKitOptions = getLiveKitOptions();

  // Apply advanced camera settings if enabled
  let videoCaptureDefaults = {
    ...liveKitOptions.videoCaptureDefaults,
    deviceId: devices.videoInput.selected$.value?.id,
    processor: processorState.processor,
  };
  let publishDefaults = liveKitOptions.publishDefaults;

  if (advancedCamera.getValue()) {
    const { width, height } = parseResolution(cameraResolution.getValue());
    const fps = cameraFramerate.getValue();
    const bps = cameraBitrate.getValue();
    const codec = cameraCodec.getValue();

    videoCaptureDefaults = {
      ...videoCaptureDefaults,
      resolution: { width, height, frameRate: fps },
    };
    publishDefaults = {
      ...publishDefaults,
      videoEncoding: { maxBitrate: bps, maxFramerate: fps },
      videoCodec: codec,
    };
  }

  return {
    ...liveKitOptions,
    videoCaptureDefaults,
    publishDefaults,
    audioCaptureDefaults: {
      ...liveKitOptions.audioCaptureDefaults,
      deviceId: devices.audioInput.selected$.value?.id,
      echoCancellation: echoCancellationSetting.getValue(),
      noiseSuppression: noiseSuppressionSetting.getValue(),
      autoGainControl: autoGainControlSetting.getValue(),
    },
    audioOutput: {
      // When using controlled audio devices, we don't want to set the
      // deviceId here, because it will be set by the native app.
      // (also the id does not need to match a browser device id)
      deviceId: controlledAudioDevices
        ? undefined
        : devices.audioOutput.selected$.value?.id,
    },
    e2ee: e2eeLivekitOptions,
    // TODO test and consider this:
    // webAudioMix: true,
  };
}