// server.js
const path = require('path');
const express = require('express');
const http = require('http');
const WebSocket = require('ws');
const mediasoup = require('mediasoup');

const app = express();
const PORT = 7860;

// Serve static files from ./public
app.use(express.static(path.join(__dirname, 'public')));

let worker, router;
const producerTransports = new Map(); // ws → { transport, producer }
const consumerTransports = new Map(); // ws → [ { transport, consumer } ]

;(async () => {
  // 1) Create the mediasoup Worker + Router
  worker = await mediasoup.createWorker();
  router = await worker.createRouter({
    mediaCodecs: [
      { kind: 'audio', mimeType: 'audio/opus', clockRate: 48000, channels: 2 },
      { kind: 'video', mimeType: 'video/VP8', clockRate: 90000 }
    ]
  });

  // 2) Expose RTP capabilities via HTTP for the clients
  app.get('/rtpCapabilities', (req, res) => {
    res.json({ rtpCapabilities: router.rtpCapabilities });
  });

  // 3) Create HTTP + WebSocket server
  const server = http.createServer(app);
  const wss = new WebSocket.Server({ server });

  wss.on('connection', ws => {
    ws.on('message', async msg => {
      const { action, data } = JSON.parse(msg);

      switch (action) {
        case 'createProducerTransport': {
          const transport = await router.createWebRtcTransport({
            listenIps: ['0.0.0.0'],
            // listenIps: ['127.0.0.1'],
            enableUdp: true,
            enableTcp: true
          });
          producerTransports.set(ws, { transport, producer: null });
          ws.send(JSON.stringify({
            action: 'producerTransportCreated',
            data: {
              id: transport.id,
              iceParameters: transport.iceParameters,
              iceCandidates: transport.iceCandidates,
              dtlsParameters: transport.dtlsParameters
            }
          }));
          break;
        }

        case 'connectProducerTransport': {
          const { dtlsParameters } = data;
          const { transport } = producerTransports.get(ws);
          await transport.connect({ dtlsParameters });
          ws.send(JSON.stringify({ action: 'producerTransportConnected' }));
          break;
        }

        case 'produce': {
          const { kind, rtpParameters } = data;
          const { transport } = producerTransports.get(ws);
          const producer = await transport.produce({ kind, rtpParameters });
          producerTransports.get(ws).producer = producer;
          ws.send(JSON.stringify({
            action: 'produced',
            data: { producerId: producer.id }
          }));
          break;
        }

        case 'createConsumerTransport': {
          const transport = await router.createWebRtcTransport({
            listenIps: ['0.0.0.0'],
            // listenIps: ['127.0.0.1'],
            enableUdp: true,
            enableTcp: true
          });
          const arr = consumerTransports.get(ws) || [];
          arr.push({ transport, consumer: null });
          consumerTransports.set(ws, arr);
          ws.send(JSON.stringify({
            action: 'consumerTransportCreated',
            data: {
              id: transport.id,
              iceParameters: transport.iceParameters,
              iceCandidates: transport.iceCandidates,
              dtlsParameters: transport.dtlsParameters
            }
          }));
          break;
        }

        case 'connectConsumerTransport': {
          const { dtlsParameters } = data;
          const arr = consumerTransports.get(ws);
          await arr[arr.length - 1].transport.connect({ dtlsParameters });
          ws.send(JSON.stringify({ action: 'consumerTransportConnected' }));
          break;
        }

        case 'consume': {
          const producerEntry = [...producerTransports.values()].find(e => e.producer);
          if (!producerEntry) {
            ws.send(JSON.stringify({ action: 'consumeError', data: 'No producer available yet' }));
            return;
          }
          const producer = producerEntry.producer;
          const arr = consumerTransports.get(ws);
          const { transport } = arr[arr.length - 1];

          const consumer = await transport.consume({
            producerId: producer.id,
            rtpCapabilities: router.rtpCapabilities,
            paused: false
          });
          arr[arr.length - 1].consumer = consumer;

          ws.send(JSON.stringify({
            action: 'consumed',
            data: {
              producerId: producer.id,
              id: consumer.id,
              kind: consumer.kind,
              rtpParameters: consumer.rtpParameters
            }
          }));
          break;
        }
      }
    });

    ws.on('close', () => {
      // Clean up transports & producers/consumers for this ws
      const pEntry = producerTransports.get(ws);
      if (pEntry) {
        pEntry.producer?.close();
        pEntry.transport.close();
        producerTransports.delete(ws);
      }
      const cEntries = consumerTransports.get(ws) || [];
      cEntries.forEach(({ consumer, transport }) => {
        consumer?.close();
        transport.close();
      });
      consumerTransports.delete(ws);
    });
  });

  // 4) Start the server
  server.listen(PORT, () => console.log(`SFU demo listening on http://localhost:${PORT}`));
})();