/*
Copyright 2023 New Vector Ltd

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

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

import { LivekitFocus } from "./LivekitFocus";
import { useActiveFocus } 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
) {
  const [sfuConfig, setSFUConfig] = useState<SFUConfig | undefined>(undefined);

  const activeFocus = useActiveFocus(rtcSession);

  useEffect(() => {
    (async () => {
      const sfuConfig = activeFocus
        ? await getSFUConfigWithOpenID(client, activeFocus)
        : undefined;
      setSFUConfig(sfuConfig);
    })();
  }, [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);
  }
}
