element-call/src/livekit/openIDSFU.ts

/*
Copyright 2023, 2024 New Vector Ltd.

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

import { type IOpenIDToken, type MatrixClient } from "matrix-js-sdk/src/matrix";
import { logger } from "matrix-js-sdk/src/logger";
import { type MatrixRTCSession } from "matrix-js-sdk/src/matrixrtc/MatrixRTCSession";
import { useEffect, useState } from "react";
import { type LivekitFocus } from "matrix-js-sdk/src/matrixrtc/LivekitFocus";

import { useActiveLivekitFocus } from "../room/useActiveFocus";

export interface SFUConfig {
  url: string;
  jwt: string;
}

export function sfuConfigEquals(a?: SFUConfig, b?: SFUConfig): boolean {
  if (a === undefined && b === undefined) return true;
  if (a === undefined || b === undefined) return false;

  return a.jwt === b.jwt && a.url === b.url;
}

// The bits we need from MatrixClient
export type OpenIDClientParts = Pick<
  MatrixClient,
  "getOpenIdToken" | "getDeviceId"
>;

export function useOpenIDSFU(
  client: OpenIDClientParts,
  rtcSession: MatrixRTCSession,
): SFUConfig | undefined {
  const [sfuConfig, setSFUConfig] = useState<SFUConfig | undefined>(undefined);

  const activeFocus = useActiveLivekitFocus(rtcSession);

  useEffect(() => {
    if (activeFocus) {
      getSFUConfigWithOpenID(client, activeFocus).then(
        (sfuConfig) => {
          setSFUConfig(sfuConfig);
        },
        (e) => {
          logger.error("Failed to get SFU config", e);
        },
      );
    } else {
      setSFUConfig(undefined);
    }
  }, [client, activeFocus]);

  return sfuConfig;
}

export async function getSFUConfigWithOpenID(
  client: OpenIDClientParts,
  activeFocus: LivekitFocus,
): Promise<SFUConfig | undefined> {
  const openIdToken = await client.getOpenIdToken();
  logger.debug("Got openID token", openIdToken);

  try {
    logger.info(
      `Trying to get JWT from call's active focus URL of ${activeFocus.livekit_service_url}...`,
    );
    const sfuConfig = await getLiveKitJWT(
      client,
      activeFocus.livekit_service_url,
      activeFocus.livekit_alias,
      openIdToken,
    );
    logger.info(`Got JWT from call's active focus URL.`);

    return sfuConfig;
  } catch (e) {
    logger.warn(
      `Failed to get JWT from RTC session's active focus URL of ${activeFocus.livekit_service_url}.`,
      e,
    );
    return undefined;
  }
}

async function getLiveKitJWT(
  client: OpenIDClientParts,
  livekitServiceURL: string,
  roomName: string,
  openIDToken: IOpenIDToken,
): Promise<SFUConfig> {
  try {
    const res = await fetch(livekitServiceURL + "/sfu/get", {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        room: roomName,
        openid_token: openIDToken,
        device_id: client.getDeviceId(),
      }),
    });
    if (!res.ok) {
      throw new Error("SFU Config fetch failed with status code " + res.status);
    }
    return await res.json();
  } catch (e) {
    throw new Error("SFU Config fetch failed with exception " + e);
  }
}