Final-Year-Project/Backend/routes/streams/sfu.ts

import { Router } from 'express';

import { mediaMode } from '../../media/config';
import { sfuService } from '../../media/sfu/service';
import { requireDeviceAuth } from '../../middleware/device-auth';
import { sfuTransportRequestSchema, streamParamSchema } from './schemas';
import { ensureStreamDeviceAuth, getOwnedStreamSession, isStreamParticipant } from './shared';

const router = Router();

router.get('/:streamSessionId/sfu/session', requireDeviceAuth, async (req, res) => {
  const parsedParams = streamParamSchema.safeParse(req.params);

  if (!parsedParams.success) {
    res.status(400).json({ message: 'Invalid streamSessionId', errors: parsedParams.error.flatten() });
    return;
  }

  const deviceAuth = ensureStreamDeviceAuth(req, res);
  if (!deviceAuth) return;

  if (!sfuService) {
    res.status(409).json({ message: `SFU service disabled (MEDIA_MODE=${mediaMode})` });
    return;
  }

  const session = await getOwnedStreamSession(parsedParams.data.streamSessionId, deviceAuth.userId);
  if (!session) {
    res.status(404).json({ message: 'Stream session not found' });
    return;
  }

  if (!isStreamParticipant(session, deviceAuth.deviceId)) {
    res.status(403).json({ message: 'Device cannot access SFU session details for this stream' });
    return;
  }

  const sfuSession = await sfuService.getSession(session.id);
  res.json({
    streamSessionId: session.id,
    mediaMode,
    sfuSession,
  });
});

router.post('/:streamSessionId/sfu/publish-transport', requireDeviceAuth, async (req, res) => {
  const parsedParams = streamParamSchema.safeParse(req.params);
  if (!parsedParams.success) {
    res.status(400).json({ message: 'Invalid streamSessionId', errors: parsedParams.error.flatten() });
    return;
  }

  const parsedBody = sfuTransportRequestSchema.safeParse(req.body ?? {});
  if (!parsedBody.success) {
    res.status(400).json({ message: 'Invalid request body', errors: parsedBody.error.flatten() });
    return;
  }

  const deviceAuth = ensureStreamDeviceAuth(req, res);
  if (!deviceAuth) return;

  if (!sfuService) {
    res.status(409).json({ message: `SFU service disabled (MEDIA_MODE=${mediaMode})` });
    return;
  }

  const session = await getOwnedStreamSession(parsedParams.data.streamSessionId, deviceAuth.userId);
  if (!session) {
    res.status(404).json({ message: 'Stream session not found' });
    return;
  }

  if (session.status !== 'streaming') {
    res.status(409).json({ message: 'Stream must be active before creating publish transport' });
    return;
  }

  if (session.cameraDeviceId !== deviceAuth.deviceId) {
    res.status(403).json({ message: 'Only camera device can create publish transport' });
    return;
  }

  const transport = await sfuService.createPublishTransport({
    streamSessionId: session.id,
    cameraDeviceId: deviceAuth.deviceId,
  });
  await sfuService.setSessionState(session.id, 'live');

  res.json({
    streamSessionId: session.id,
    mediaMode,
    transport,
  });
});

router.post('/:streamSessionId/sfu/subscribe-transport', requireDeviceAuth, async (req, res) => {
  const parsedParams = streamParamSchema.safeParse(req.params);
  if (!parsedParams.success) {
    res.status(400).json({ message: 'Invalid streamSessionId', errors: parsedParams.error.flatten() });
    return;
  }

  const parsedBody = sfuTransportRequestSchema.safeParse(req.body ?? {});
  if (!parsedBody.success) {
    res.status(400).json({ message: 'Invalid request body', errors: parsedBody.error.flatten() });
    return;
  }

  const deviceAuth = ensureStreamDeviceAuth(req, res);
  if (!deviceAuth) return;

  if (!sfuService) {
    res.status(409).json({ message: `SFU service disabled (MEDIA_MODE=${mediaMode})` });
    return;
  }

  const session = await getOwnedStreamSession(parsedParams.data.streamSessionId, deviceAuth.userId);
  if (!session) {
    res.status(404).json({ message: 'Stream session not found' });
    return;
  }

  if (session.status !== 'streaming') {
    res.status(409).json({ message: 'Stream must be active before creating subscribe transport' });
    return;
  }

  if (!isStreamParticipant(session, deviceAuth.deviceId)) {
    res.status(403).json({ message: 'Device cannot create subscribe transport for this stream' });
    return;
  }

  const transport = await sfuService.createSubscribeTransport({
    streamSessionId: session.id,
    viewerDeviceId: deviceAuth.deviceId,
  });
  await sfuService.setSessionState(session.id, 'live');

  res.json({
    streamSessionId: session.id,
    mediaMode,
    transport,
  });
});

export default router;