feat: add peer listing and graceful shutdown

- Add `/who` command to list active users via new `/api/peers` endpoint
- Implement graceful shutdown for server and swarm with proper cleanup
- Enhance SSE broadcast with client connection state checks
- Expose peer list in stats and add health endpoint
- Fix theme color refresh for network visualization

public/app.js

@@ -4,6 +4,8 @@ const totalUniqueEl = document.getElementById("total-unique");
 const canvas = document.getElementById("network");
 const ctx = canvas.getContext("2d");
 let particles = [];
+let particleColor = "#4ade80";
+let particleLinkColor = "#22d3ee";
 
 function getThemeColor(varName) {
   return getComputedStyle(document.documentElement)
@@ -11,6 +13,11 @@ function getThemeColor(varName) {
     .trim();
 }
 
+const refreshThemeColors = () => {
+  particleColor = getThemeColor("--color-particle");
+  particleLinkColor = getThemeColor("--color-particle-link");
+};
+
 function resize() {
   canvas.width = window.innerWidth;
   canvas.height = window.innerHeight;
@@ -39,7 +46,7 @@ class Particle {
   draw() {
     ctx.beginPath();
     ctx.arc(this.x, this.y, this.size, 0, Math.PI * 2);
-    ctx.fillStyle = getThemeColor("--color-particle");
+    ctx.fillStyle = particleColor;
     ctx.fill();
   }
 }
@@ -62,15 +69,15 @@ const updateParticles = (count) => {
 const animate = () => {
   ctx.clearRect(0, 0, canvas.width, canvas.height);
 
-  ctx.strokeStyle = getThemeColor("--color-particle-link");
+  ctx.strokeStyle = particleLinkColor;
   ctx.lineWidth = 1;
   for (let i = 0; i < particles.length; i++) {
     for (let j = i + 1; j < particles.length; j++) {
       const dx = particles[i].x - particles[j].x;
       const dy = particles[i].y - particles[j].y;
-      const distance = Math.sqrt(dx * dx + dy * dy);
+      const distanceSquared = dx * dx + dy * dy;
 
-      if (distance < 150) {
+      if (distanceSquared < 22500) {
         ctx.beginPath();
         ctx.moveTo(particles[i].x, particles[i].y);
         ctx.lineTo(particles[j].x, particles[j].y);
@@ -473,6 +480,17 @@ const getColorFromId = (id) => {
 const seenMessageIds = new Set();
 const messageIdHistory = [];
 
+const appendSystemLines = (lines) => {
+  const entries = Array.isArray(lines) ? lines : [lines];
+  for (const line of entries) {
+    const div = document.createElement("div");
+    div.className = "system-message";
+    div.innerText = `[SYSTEM] ${line}`;
+    terminalOutput.appendChild(div);
+  }
+  terminalOutput.scrollTop = terminalOutput.scrollHeight;
+};
+
 const appendMessage = (msg) => {
   const div = document.createElement("div");
 
@@ -631,6 +649,39 @@ terminalInput.addEventListener("keypress", async (e) => {
         }
       }
       return;
+    } else if (content === "/who") {
+      try {
+        const res = await fetch("/api/peers");
+        if (!res.ok) {
+          systemStatusBar.innerText = "[SYSTEM] Failed to fetch peer list";
+          return;
+        }
+
+        const data = await res.json();
+        const peers = Array.isArray(data.peers) ? data.peers : [];
+        const mappedPeers = peers.map((peer) => {
+          if (peer.id && peer.screenname) {
+            nameToId.set(peer.screenname, peer.id);
+          }
+          const shortId = peer.id ? peer.id.slice(-8) : "unknown";
+          return `${peer.screenname || "Unknown"} (...${shortId})`;
+        });
+
+        const visiblePeers = mappedPeers.slice(0, 20);
+        const outputLines = [
+          `Active users: ${mappedPeers.length}`,
+          ...visiblePeers,
+        ];
+        if (mappedPeers.length > visiblePeers.length) {
+          outputLines.push(`...and ${mappedPeers.length - visiblePeers.length} more`);
+        }
+
+        appendSystemLines(outputLines);
+        systemStatusBar.innerText = `[SYSTEM] Listed ${mappedPeers.length} active users`;
+      } catch (err) {
+        systemStatusBar.innerText = "[SYSTEM] Failed to fetch peer list";
+      }
+      return;
     } else if (content.startsWith("/whisper ")) {
       const parts = content.split(" ");
       if (parts.length < 3) {
@@ -840,6 +891,7 @@ const initialCount = parseInt(countEl.dataset.initialCount) || 0;
 countEl.innerText = initialCount;
 countEl.classList.add("loaded");
 updateParticles(initialCount);
+refreshThemeColors();
 animate();
 
 const bandwidthHistory = { timestamps: [], bytesIn: [], bytesOut: [] };
@@ -1040,6 +1092,7 @@ function cycleTheme() {
     if (oldLink) oldLink.remove();
     newLink.id = "theme-css";
     localStorage.setItem("hypermind-theme", newTheme);
+    refreshThemeColors();
     btn.disabled = false;
     btn.style.opacity = "";
     showThemeNotification(newTheme);

public/js/chat-commands/help.js

@@ -40,6 +40,7 @@ export const helpCommand = {
       },
       { cmd: "/block <user>", desc: "Block messages from a user" },
       { cmd: "/unblock <user>", desc: "Unblock a user" },
+      { cmd: "/who", desc: "List active users in the swarm" },
       {
         cmd: "/local <msg>",
         desc: "Send message to direct peers only (Global by default)",

server.js

@@ -65,16 +65,24 @@ const main = async () => {
     () => swarmManager.getSwarm().connections.size
   );
 
-  setInterval(() => {
+  const diagnosticsTimer = setInterval(() => {
     broadcastUpdate();
   }, DIAGNOSTICS_INTERVAL);
+  diagnosticsTimer.unref();
 
   const app = createServer(identity, peerManager, swarmManager, sseManager, diagnostics);
-  startServer(app, identity);
+  const webServer = startServer(app, identity);
 
-  const handleShutdown = () => {
+  let shuttingDown = false;
+  const handleShutdown = async () => {
+    if (shuttingDown) return;
+    shuttingDown = true;
+    clearInterval(diagnosticsTimer);
     diagnostics.stopLogging();
-    swarmManager.shutdown();
+    await swarmManager.shutdown();
+    webServer.close(() => {
+      process.exit(0);
+    });
   };
 
   process.on("SIGINT", handleShutdown);

src/p2p/messaging.js

@@ -7,7 +7,6 @@ const crypto = require("crypto");
 const {
   MAX_RELAY_HOPS,
   ENABLE_CHAT,
-  CHAT_RATE_LIMIT,
 } = require("../config/constants");
 const { BloomFilterManager } = require("../state/bloom");
 const { generateScreenname } = require("../utils/name-generator");

src/p2p/swarm.js

@@ -2,13 +2,11 @@ const Hyperswarm = require("hyperswarm");
 const { signMessage } = require("../core/security");
 const {
   TOPIC,
-  TOPIC_NAME,
   HEARTBEAT_INTERVAL,
   MAX_CONNECTIONS,
   CONNECTION_ROTATION_INTERVAL,
   ENABLE_CHAT,
 } = require("../config/constants");
-const { generateScreenname } = require("../utils/name-generator");
 
 class SwarmManager {
   constructor(
@@ -122,6 +120,7 @@ class SwarmManager {
         this.broadcastFn();
       }
     }, HEARTBEAT_INTERVAL);
+    this.heartbeatInterval.unref();
   }
 
   startRotation() {
@@ -148,9 +147,10 @@ class SwarmManager {
         oldest.destroy();
       }
     }, CONNECTION_ROTATION_INTERVAL);
+    this.rotationInterval.unref();
   }
 
-  shutdown() {
+  async shutdown() {
     const sig = signMessage(
       `type:LEAVE:${this.identity.id}`,
       this.identity.privateKey
@@ -176,10 +176,8 @@ class SwarmManager {
     if (this.rotationInterval) {
       clearInterval(this.rotationInterval);
     }
-
-    setTimeout(() => {
-      process.exit(0);
-    }, 500);
+    this.messageHandler.bloomFilter.stop();
+    await this.swarm.destroy();
   }
 
   getSwarm() {

src/state/peers.js

@@ -92,6 +92,19 @@ class PeerManager {
         }
         return peers;
     }
+
+    getPeerList() {
+        const peers = [];
+        for (const [id, data] of this.seenPeers.entries()) {
+            peers.push({
+                id,
+                seq: data.seq,
+                lastSeen: data.lastSeen,
+                ip: data.ip || null,
+            });
+        }
+        return peers;
+    }
 }
 
 module.exports = { PeerManager };

src/web/routes.js

@@ -48,6 +48,7 @@ const setupRoutes = (
     peerManager,
     swarm,
     diagnostics,
+    sseManager,
   };
 
   const chatDeps = {

src/web/routes/stats.js

@@ -1,4 +1,5 @@
-const { ENABLE_CHAT } = require("../../config/constants");
+const { ENABLE_CHAT, ENABLE_MAP } = require("../../config/constants");
+const { generateScreenname } = require("../../utils/name-generator");
 
 const setupStatsRoutes = (router, dependencies) => {
     const { peerManager, swarm, diagnostics } = dependencies;
@@ -12,9 +13,38 @@ const setupStatsRoutes = (router, dependencies) => {
             screenname: dependencies.identity.screenname,
             diagnostics: diagnostics.getStats(),
             chatEnabled: ENABLE_CHAT,
+            mapEnabled: ENABLE_MAP,
             peers: peerManager.getPeersWithIps(),
         });
     });
+
+    router.get("/api/health", (req, res) => {
+        res.json({
+            status: "ok",
+            uptime: process.uptime(),
+            peers: peerManager.size,
+            direct: swarm.getSwarm().connections.size,
+            sseClients: dependencies.sseManager ? dependencies.sseManager.size : 0,
+            timestamp: Date.now(),
+        });
+    });
+
+    router.get("/api/peers", (req, res) => {
+        const peers = peerManager
+            .getPeerList()
+            .sort((a, b) => b.lastSeen - a.lastSeen)
+            .map((peer) => ({
+                id: peer.id,
+                screenname: generateScreenname(peer.id),
+                lastSeen: peer.lastSeen,
+                ip: peer.ip,
+            }));
+
+        res.json({
+            count: peers.length,
+            peers,
+        });
+    });
 };
 
 module.exports = { setupStatsRoutes };

src/web/server.js

@@ -11,10 +11,11 @@ const createServer = (identity, peerManager, swarm, sseManager, diagnostics) =>
 }
 
 const startServer = (app, identity) => {
-    app.listen(PORT, () => {
+    const server = app.listen(PORT, () => {
         console.log(`Hypermind Node running on port ${PORT}`);
         console.log(`ID: ${identity.id}`);
     });
+    return server;
 }
 
 module.exports = { createServer, startServer };

src/web/sse.js

@@ -25,7 +25,15 @@ class SSEManager {
     broadcast(data) {
         const message = JSON.stringify(data);
         for (const client of this.clients) {
-            client.write(`data: ${message}\n\n`);
+            if (client.writableEnded || client.destroyed) {
+                this.clients.delete(client);
+                continue;
+            }
+            try {
+                client.write(`data: ${message}\n\n`);
+            } catch (e) {
+                this.clients.delete(client);
+            }
         }
     }
 

test-api.js

@@ -72,6 +72,10 @@ const test = (method, path, body = null, validate, timeout = 5000) => {
             const json = JSON.parse(data);
             return json.count !== undefined && json.id && json.screenname && json.diagnostics;
         }),
+        test("GET", "/api/peers", null, (data) => {
+            const json = JSON.parse(data);
+            return typeof json.count === "number" && Array.isArray(json.peers);
+        }),
         test("GET", "/api/github/latest-release", null, (data) => {
             const json = JSON.parse(data);
             return json.tag_name && json.html_url;