const path = require('path');
const http = require('http');
const express = require('express');
const dgram = require('dgram');
const { WebSocketServer } = require('ws');

const HTTP_PORT = process.env.PORT || 3000;
const UDP_BROADCAST_PORT = Number(process.env.UDP_PORT) || 4210;
const UDP_BROADCAST_ADDR = process.env.UDP_ADDR || '255.255.255.255';

const MATRIX_WIDTH = Number(process.env.MATRIX_WIDTH) || 16;
const MATRIX_HEIGHT = Number(process.env.MATRIX_HEIGHT) || 16;
const BYTES_PER_PIXEL = 3;

const app = express();
app.use(express.static(path.join(__dirname, 'public')));

const server = http.createServer(app);
const wss = new WebSocketServer({ server, path: '/ws' });

const udpSocket = dgram.createSocket('udp4');
udpSocket.on('error', (err) => {
  console.error('[UDP] error:', err);
});
udpSocket.bind(() => {
  try {
    udpSocket.setBroadcast(true);
    console.log(`[UDP] Ready to broadcast on ${UDP_BROADCAST_ADDR}:${UDP_BROADCAST_PORT}`);
  } catch (e) {
    console.error('[UDP] setBroadcast failed:', e);
  }
});

wss.on('connection', (ws, req) => {
  const clientAddress = req?.socket?.remoteAddress || 'unknown';
  console.log(`[WS] Client connected: ${clientAddress}`);

  ws.on('message', (data) => {
    const bufferToSend = Buffer.isBuffer(data)
      ? data
      : (data instanceof ArrayBuffer ? Buffer.from(data) : Buffer.from(String(data)));

    const expectedSize = MATRIX_WIDTH * MATRIX_HEIGHT * BYTES_PER_PIXEL;
    if (bufferToSend.length !== expectedSize) {
      console.warn(`[WS] Unexpected frame size: ${bufferToSend.length} bytes (expected ${expectedSize}).`);
    }

    const hexPayload = bufferToSend.toString('hex');
    const udpPayload = Buffer.from(`RAW:${hexPayload}`, 'ascii');

    udpSocket.send(
      udpPayload,
      UDP_BROADCAST_PORT,
      UDP_BROADCAST_ADDR,
      (err) => {
        if (err) {
          console.error('[UDP] send error:', err.message);
        }
      }
    );
  });

  ws.on('close', () => {
    console.log('[WS] Client disconnected');
  });

  ws.on('error', (err) => {
    console.error('[WS] error:', err.message);
  });
});

server.listen(HTTP_PORT, () => {
  console.log(`Server listening on http://localhost:${HTTP_PORT}`);
});

process.on('SIGINT', () => {
  console.log('Shutting down...');
  try { udpSocket.close(); } catch {}
  try { server.close(() => process.exit(0)); } catch {}
});