/*
Copyright 2022-2024 New Vector Ltd.

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

import { useEffect, useMemo, useRef, FC, ReactNode, useCallback } from "react";
import useMeasure from "react-use-measure";
import { usePreviewTracks } from "@livekit/components-react";
import { LocalVideoTrack, Track } from "livekit-client";
import classNames from "classnames";
import { logger } from "matrix-js-sdk/src/logger";

import { Avatar } from "../Avatar";
import styles from "./VideoPreview.module.css";
import { useMediaDevices } from "../livekit/MediaDevicesContext";
import { MuteStates } from "./MuteStates";
import { useInitial } from "../useInitial";
import { EncryptionSystem } from "../e2ee/sharedKeyManagement";

export type MatrixInfo = {
  userId: string;
  displayName: string;
  avatarUrl: string;
  roomId: string;
  roomName: string;
  roomAlias: string | null;
  roomAvatar: string | null;
  e2eeSystem: EncryptionSystem;
};

interface Props {
  matrixInfo: MatrixInfo;
  muteStates: MuteStates;
  children: ReactNode;
}

export const VideoPreview: FC<Props> = ({
  matrixInfo,
  muteStates,
  children,
}) => {
  const [previewRef, previewBounds] = useMeasure();

  const devices = useMediaDevices();

  // Capture the audio options as they were when we first mounted, because
  // we're not doing anything with the audio anyway so we don't need to
  // re-open the devices when they change (see below).
  const initialAudioOptions = useInitial(
    () =>
      muteStates.audio.enabled && { deviceId: devices.audioInput.selectedId },
  );

  const localTrackOptions = useMemo(
    () => ({
      // The only reason we request audio here is to get the audio permission
      // request over with at the same time. But changing the audio settings
      // shouldn't cause this hook to recreate the track, which is why we
      // reference the initial values here.
      // We also pass in a clone because livekit mutates the object passed in,
      // which would cause the devices to be re-opened on the next render.
      audio: Object.assign({}, initialAudioOptions),
      video: muteStates.video.enabled && {
        deviceId: devices.videoInput.selectedId,
      },
    }),
    [
      initialAudioOptions,
      devices.videoInput.selectedId,
      muteStates.video.enabled,
    ],
  );

  const onError = useCallback(
    (error: Error) => {
      logger.error("Error while creating preview Tracks:", error);
      muteStates.audio.setEnabled?.(false);
      muteStates.video.setEnabled?.(false);
    },
    [muteStates.audio, muteStates.video],
  );

  const tracks = usePreviewTracks(localTrackOptions, onError);

  const videoTrack = useMemo(
    () =>
      tracks?.find((t) => t.kind === Track.Kind.Video) as
        | LocalVideoTrack
        | undefined,
    [tracks],
  );

  const videoEl = useRef<HTMLVideoElement | null>(null);

  useEffect(() => {
    // Effect to connect the videoTrack with the video element.
    if (videoEl.current) {
      videoTrack?.attach(videoEl.current);
    }
    return (): void => {
      videoTrack?.detach();
    };
  }, [videoTrack]);

  return (
    <div className={classNames(styles.preview)} ref={previewRef}>
      <video
        ref={videoEl}
        muted
        playsInline
        // There's no reason for this to be focusable
        tabIndex={-1}
        disablePictureInPicture
      />
      {!muteStates.video.enabled && (
        <div className={styles.avatarContainer}>
          <Avatar
            id={matrixInfo.userId}
            name={matrixInfo.displayName}
            size={Math.min(previewBounds.width, previewBounds.height) / 2}
            src={matrixInfo.avatarUrl}
          />
        </div>
      )}
      <div className={styles.buttonBar}>{children}</div>
    </div>
  );
};