deskreen/app/features/PeerConnection/handlePeerOnData.ts

import DesktopCapturerSourceType from '../DesktopCapturerSourcesService/DesktopCapturerSourceType';
import getDesktopSourceStreamBySourceID from './getDesktopSourceStreamBySourceID';
import prepareDataMessageToSendScreenSourceType from './prepareDataMessageToSendScreenSourceType';

export default async function handlePeerOnData(
  peerConnection: PeerConnection,
  data: string
) {
  const dataJSON = JSON.parse(data);

  if (dataJSON.type === 'set_video_quality') {
    const maxVideoQualityMultiplier = dataJSON.payload.value;
    const minVideoQualityMultiplier =
      maxVideoQualityMultiplier === 1 ? 0.5 : maxVideoQualityMultiplier;

    if (
      !peerConnection.desktopCapturerSourceID.includes(
        DesktopCapturerSourceType.SCREEN
      )
    )
      return;

    const newStream = await getDesktopSourceStreamBySourceID(
      peerConnection.desktopCapturerSourceID,
      peerConnection.sourceDisplaySize?.width,
      peerConnection.sourceDisplaySize?.height,
      minVideoQualityMultiplier,
      maxVideoQualityMultiplier
    );
    const newVideoTrack = newStream.getVideoTracks()[0];
    const oldTrack = peerConnection.localStream?.getVideoTracks()[0];

    if (oldTrack && peerConnection.localStream) {
      peerConnection.peer.replaceTrack(
        oldTrack,
        newVideoTrack,
        peerConnection.localStream
      );
      oldTrack.stop();
    }
  }

  if (dataJSON.type === 'get_sharing_source_type') {
    const sourceType = peerConnection.desktopCapturerSourceID.includes(
      DesktopCapturerSourceType.SCREEN
    )
      ? DesktopCapturerSourceType.SCREEN
      : DesktopCapturerSourceType.WINDOW;

    peerConnection.peer.send(
      prepareDataMessageToSendScreenSourceType(sourceType)
    );
  }
}