refactor for multiple sessions

discovery.ts

@@ -0,0 +1,50 @@
+import EventEmitter from "node:events";
+import { create_LanSearch, parse_PunchPkt } from "./impl.js";
+import { createSocket, RemoteInfo } from "node:dgram";
+import { Commands } from "./datatypes.js";
+import { hexdump } from "./hexdump.js";
+import { opt } from "./options.js";
+
+const handleIncomingPunch = (msg: Buffer, ee: EventEmitter, rinfo: RemoteInfo, options: opt) => {
+  const ab = new Uint8Array(msg).buffer;
+  const dv = new DataView(ab);
+  const cmd_id = dv.readU16();
+  if (cmd_id != Commands.PunchPkt) {
+    return;
+  }
+  if (options.debug) {
+    console.log("Discovery got a PunchPkt");
+  }
+  ee.emit("discover", rinfo, parse_PunchPkt(dv));
+};
+
+export const discoverDevices = (options: opt): EventEmitter => {
+  const sock = createSocket("udp4");
+  //const BCAST_IP = "192.168.1.255";
+  const BCAST_IP = "192.168.40.101";
+  const SEND_PORT = 32108;
+  const ee = new EventEmitter();
+
+  sock.on("error", (err) => {
+    console.error(`sock error:\n${err.stack}`);
+    sock.close();
+  });
+
+  sock.on("message", (msg, rinfo) => handleIncomingPunch(msg, ee, rinfo, options));
+
+  sock.on("listening", () => {
+    sock.setBroadcast(true);
+    console.log("Searching for devices..");
+
+    let buf = create_LanSearch();
+    setInterval(() => {
+      console.log(".");
+      sock.send(new Uint8Array(buf.buffer), SEND_PORT, BCAST_IP);
+    }, 2000);
+    sock.send(new Uint8Array(buf.buffer), SEND_PORT, BCAST_IP);
+  });
+
+  sock.bind();
+
+  return ee;
+};