import {
  FunctionComponent,
  useCallback,
  useEffect,
  useRef,
  useState,
} from "react";
import styles from "./ScreenViewer.module.css";
import {
  ScreenSharingClient,
  StateChangedEvent,
  StateChangedEventType,
  StreamChangedEvent,
  StreamChangedEventType,
} from "../../api/webrtc";

export interface ScreenViewerProps {
  sessionId: string;
}

export const ScreenViewer: FunctionComponent<ScreenViewerProps> = ({
  sessionId,
}) => {
  const videoRef = useRef<HTMLVideoElement>(null);
  const [client, setClient] = useState<ScreenSharingClient | null>(null);
  const [stream, setStream] = useState<MediaStream | null>(null);
  const [state, setState] = useState<string | null>(null);

  const onStreamChanged = useCallback((evt: Event) => {
    setStream((evt as StreamChangedEvent).stream);
  }, []);

  const onStateChanged = useCallback((evt: Event) => {
    setState((evt as StateChangedEvent).state);
  }, []);

  useEffect(() => {
    const client = new ScreenSharingClient(sessionId);

    client.addEventListener(StreamChangedEventType, onStreamChanged);
    client.addEventListener(StateChangedEventType, onStateChanged);
    client.connect();
    setClient(client);

    return () => {
      client.removeEventListener(StreamChangedEventType, onStreamChanged);
      client.removeEventListener(StateChangedEventType, onStateChanged);
      client.close();
      setClient(null);
    };
  }, [sessionId, onStreamChanged, onStateChanged]);

  useEffect(() => {
    if (!videoRef.current) return;

    const video = videoRef.current;

    console.log("Changing video stream", video, stream);

    video.autoplay = true;
    video.playsInline = true;
    video.srcObject = stream;
    video.muted = true;
  }, [videoRef, stream]);

  const isVideoReady = state === "connected" && stream !== null;

  console.log("isVideoReady", isVideoReady);

  return (
    <div className={styles.root}>
      <h1
        style={{
          display: `${isVideoReady ? "none" : "block"}`,
        }}
      >
        <ConnectionState state={state} />
      </h1>
      <video
        ref={videoRef}
        className={styles.video}
        style={{
          display: `${isVideoReady ? "block" : "none"}`,
        }}
      ></video>
    </div>
  );
};

export interface ConnectionStateProps {
  state: string | null;
}

export const ConnectionState: FunctionComponent<ConnectionStateProps> = ({
  state,
}) => {
  switch (state) {
    case null:
      return <span>Connecting...</span>;
    case "Connecté":
      return <span>Connection established !</span>;
    case "disconnected":
      return <span>Connection lost !</span>;
    case "failed":
      return <span>Connection failed !</span>;
    default:
      return (
        <span>
          État inconnu (<code>{state}</code>)
        </span>
      );
  }
};