import cluster from "cluster";
import os from "os";
import net from "net";
import express from "express";
import { createServer } from "http";
import path from "path";
import compression from "compression";
import WebSocket from "ws";
import { baremuxPath } from "@mercuryworkshop/bare-mux/node";
import { epoxyPath } from "@mercuryworkshop/epoxy-transport";
import { libcurlPath } from "@mercuryworkshop/libcurl-transport";
import { uvPath } from "@titaniumnetwork-dev/ultraviolet";
import wisp from "wisp-server-node";
import NodeCache from "node-cache";

const cache = new NodeCache({ stdTTL: 345600, checkperiod: 3600 });
const port = parseInt(process.env.PORT || "3000", 10);
cluster.schedulingPolicy = cluster.SCHED_RR;

function logInfo(message) {
  console.info(`[~] ${message}`);
}
function logSuccess(message) {
  console.info(`[+] ${message}`);
}
function logError(error) {
  const msg = error instanceof Error ? error.message : error;
  console.error(`[!] ${msg}`);
}

process.on("uncaughtException", (err) => logError(`Unhandled Exception: ${err}`));
process.on("unhandledRejection", (reason) => logError(`Unhandled Promise Rejection: ${reason}`));

if (cluster.isPrimary) {
  const numCPUs = os.cpus().length;
  logInfo(`Master started. Forking ${numCPUs} workers...`);

  for (let i = 0; i < numCPUs; i++) {
    cluster.fork();
  }

  cluster.on("exit", (worker, code, signal) => {
    logError(`Worker ${worker.process.pid} terminated (code: ${code}, signal: ${signal}). Restarting...`);
    cluster.fork();
  });

  let currentWorker = 0;
  const server = net.createServer({ pauseOnConnect: true }, (connection) => {
    const workerIds = Object.keys(cluster.workers);
    if (workerIds.length === 0) {
      connection.destroy();
      return;
    }
    const worker = cluster.workers[workerIds[currentWorker % workerIds.length]];
    currentWorker++;
    if (worker) worker.send("sticky-session:connection", connection);
  });

  server.on("error", (err) => logError(`Server error: ${err}`));
  server.listen(port, () => logSuccess(`Server running on port ${port}.`));

} else {
  process.env.UV_THREADPOOL_SIZE = String(os.cpus().length * 2);
  const __dirname = process.cwd();
  const publicPath = path.join(__dirname, "public");
  const app = express();

  app.use(compression({ level: 9, threshold: 128, memLevel: 9 }));

  app.use((req, res, next) => {
    const key = req.originalUrl;
    if (cache.has(key)) {
      res.setHeader("X-Cache", "HIT");
      return res.send(cache.get(key));
    }
    res.sendResponse = res.send;
    res.send = (body) => {
      cache.set(key, body);
      res.setHeader("X-Cache", "MISS");
      res.sendResponse(body);
    };
    next();
  });

  const staticOpts = { maxAge: "7d", immutable: true };
  app.use("/baremux/", express.static(baremuxPath, staticOpts));
  app.use("/epoxy/", express.static(epoxyPath, staticOpts));
  app.use("/libcurl/", express.static(libcurlPath, staticOpts));
  app.use(express.static(publicPath, staticOpts));
  app.use("/wah/", express.static(uvPath, staticOpts));

  app.use(express.json());
  const sendHtml = (file) => (req, res) => res.sendFile(path.join(publicPath, file));
  app.get('/', sendHtml('$.html'));
  app.get('/g', sendHtml('!.html'));
  app.get('/a', sendHtml('!!.html'));
  app.get('/resent', (req, res) => res.sendFile(path.join(publicPath, 'resent', 'index.html')));
  app.use((req, res) => res.status(404).sendFile(path.join(publicPath, '404.html')));

  const server = createServer(app);
  server.keepAliveTimeout = 0;
  server.headersTimeout = 0;

  const pingWSS = new WebSocket.Server({ noServer: true, maxPayload: 1048576 });
  pingWSS.on("connection", (ws, req) => {
    const remoteAddress = req.socket.remoteAddress || "unknown";
    let latencies = [];
    const interval = setInterval(() => {
      if (ws.readyState === WebSocket.OPEN) {
        const ts = Date.now();
        ws.send(JSON.stringify({ type: 'ping', timestamp: ts }));
      }
    }, 1000);

    ws.on('message', (message) => {
      try {
        const data = JSON.parse(message);
        if (data.type === 'pong' && data.timestamp) {
          const latency = Date.now() - data.timestamp;
          latencies.push(latency);
          if (latencies.length > 5) latencies.shift();
          ws.send(JSON.stringify({ type: 'latency', latency }));
        }
      } catch (err) {
        logError(`Ping handling error: ${err}`);
      }
    });

    ws.on('close', () => {
      clearInterval(interval);
      const avg = latencies.length ? (latencies.reduce((a, b) => a + b) / latencies.length).toFixed(2) : 0;
      logInfo(`Connection from ${remoteAddress} closed. Avg latency: ${avg}ms.`);
    });
  });

  server.on('upgrade', (req, socket, head) => {
    if (req.url === '/w/ping') {
      pingWSS.handleUpgrade(req, socket, head, (ws) => pingWSS.emit('connection', ws, req));
    } else if (req.url.startsWith('/w/')) {
      wisp.routeRequest(req, socket, head);
    } else {
      socket.end();
    }
  });

  server.on('error', (err) => logError(`Worker server error: ${err}`));

  server.listen(0, () => logSuccess(`Worker ${process.pid} ready and listening.`));

  process.on('message', (msg, conn) => {
    if (msg === 'sticky-session:connection' && conn) {
      server.emit('connection', conn);
      conn.resume();
    }
  });
}