solution

.claude/settings.local.json

@@ -0,0 +1,8 @@
+{
+  "permissions": {
+    "allow": [
+      "Bash(ls C:/Users/Hanna/projects/node/node_chat/.eslint* 2>/dev/null; ls C:/Users/Hanna/projects/node/node_chat/src/public/.eslint* 2>/dev/null; cat C:/Users/Hanna/projects/node/node_chat/package.json | grep -A 20 eslint)",
+      "Bash(cd C:/Users/Hanna/projects/node/node_chat && node -e \"\nconst WebSocket = require\\('ws'\\);\n\nprocess.env.PORT = 3002;\nrequire\\('./src/index.js'\\);\n\nsetTimeout\\(\\(\\) => {\n  const ws = new WebSocket\\('ws://localhost:3002'\\);\n  let step = 0;\n  ws.on\\('open', \\(\\) => {\n    ws.send\\(JSON.stringify\\({ type: 'set_username', username: 'testuser' }\\)\\);\n  }\\);\n  ws.on\\('message', \\(data\\) => {\n    const msg = JSON.parse\\(data\\);\n    console.log\\('MSG:', JSON.stringify\\(msg\\)\\);\n    if \\(msg.type === 'username_confirmed'\\) {\n      // Test: send create_room with empty name \\(simulate the bug\\)\n      ws.send\\(JSON.stringify\\({ type: 'create_room', name: '' }\\)\\);\n    }\n    if \\(msg.type === 'error' || \\(msg.type === 'room_created' && step === 0\\)\\) {\n      step++;\n      // Now test with actual name\n      ws.send\\(JSON.stringify\\({ type: 'create_room', name: 'test' }\\)\\);\n    }\n    if \\(msg.type === 'room_created' && step === 1\\) {\n      setTimeout\\(\\(\\) => process.exit\\(0\\), 100\\);\n    }\n  }\\);\n}, 200\\);\n\" 2>&1)"
+    ]
+  }
+}

.eslintrc.js

@@ -1,10 +1,10 @@
 module.exports = {
   extends: '@mate-academy/eslint-config',
   env: {
-    jest: true
+    jest: true,
   },
   rules: {
-    'no-proto': 0
+    'no-proto': 0,
   },
-  plugins: ['jest']
+  plugins: ['jest'],
 };

.github/workflows/test.yml-template

@@ -0,0 +1,23 @@
+name: Test
+
+on:
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [20.x]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: npm install
+    - run: npm test

package.json

@@ -15,9 +15,12 @@
   },
   "author": "Mate academy",
   "license": "GPL-3.0",
+  "dependencies": {
+    "ws": "^8.18.0"
+  },
   "devDependencies": {
     "@mate-academy/eslint-config": "latest",
-    "@mate-academy/scripts": "^1.8.6",
+    "@mate-academy/scripts": "^2.1.3",
     "eslint": "^8.57.0",
     "eslint-plugin-jest": "^28.6.0",
     "eslint-plugin-node": "^11.1.0",

src/index.js

@@ -1 +1,267 @@
 'use strict';
+
+const http = require('http');
+const path = require('path');
+const fs = require('fs');
+const { WebSocketServer } = require('ws');
+
+const PORT = process.env.PORT || 3000;
+const PUBLIC_DIR = path.join(__dirname, 'public');
+
+// ─── In-memory state ─────────────────────────────────────────────────────────
+
+const rooms = new Map(); // roomId → { id, name, messages[] }
+const clients = new Map(); // ws → { username, roomId }
+
+let nextRoomId = 1;
+
+function createRoom(roomName) {
+  const id = String(nextRoomId++);
+
+  rooms.set(id, { id, name: roomName, messages: [] });
+
+  return rooms.get(id);
+}
+
+// Seed a default room so the app is usable right away
+createRoom('general');
+
+// ─── HTTP server (serves static client files) ────────────────────────────────
+
+const MIME = {
+  '.html': 'text/html',
+  '.js': 'application/javascript',
+  '.css': 'text/css',
+  '.ico': 'image/x-icon',
+};
+
+const server = http.createServer((req, res) => {
+  const filePath = path.join(
+    PUBLIC_DIR,
+    req.url === '/' ? 'index.html' : req.url,
+  );
+
+  const ext = path.extname(filePath);
+  const contentType = MIME[ext] || 'tsxt/plain';
+
+  fs.readFile(filePath, (err, data) => {
+    if (err) {
+      res.writeHead(404);
+      res.end('Not found');
+
+      return;
+    }
+
+    res.writeHead(200, { 'Content-Type': contentType });
+    res.end(data);
+  });
+});
+
+// ─── WebSocket helpers ───────────────────────────────────────────────────────
+
+function send(ws, type, payload = {}) {
+  if (ws.readyState === ws.OPEN) {
+    ws.send(JSON.stringify({ type, ...payload }));
+  }
+}
+
+function broadcast(roomId, type, payload, excludeWs = null) {
+  for (const [ws, client] of clients) {
+    if (client.roomId === roomId && ws !== excludeWs) {
+      send(ws, type, payload);
+    }
+  }
+}
+
+function broadcastRoomList() {
+  // eslint-disable-next-line
+  const roomList = [...rooms.values()].map(({ id, name }) => ({
+    id,
+    name,
+  }));
+
+  for (const ws of clients.keys()) {
+    send(ws, 'room_list', { rooms: roomList });
+  }
+}
+
+// ─── Message handlers ────────────────────────────────────────────────────────
+
+const handlers = {
+  set_username(ws, { username }) {
+    if (!username || !username.trim()) {
+      send(ws, 'error', { message: 'User name cannot be empty' });
+
+      return;
+    }
+
+    clients.get(ws).username = username.trim();
+    send(ws, 'username_confirmed', { username: username.trim() });
+
+    send(ws, 'room_list', {
+      rooms: [...rooms.values()].map(({ id, name }) => ({ id, name })),
+    });
+  },
+
+  create_room(ws, { name }) {
+    if (!name || !name.trim()) {
+      send(ws, 'error', { message: 'Room name cannot be empty' });
+
+      return;
+    }
+
+    const room = createRoom(name.trim());
+
+    broadcastRoomList();
+
+    send(ws, 'room_created', { room: { id: room.id, name: room.name } });
+  },
+
+  rename_room(ws, { roomId, name }) {
+    const room = rooms.get(roomId);
+
+    if (!room) {
+      send(ws, 'error', { message: 'Room not found' });
+
+      return;
+    }
+
+    if (!name || !name.trim()) {
+      send(ws, 'error', { message: 'Room name cannot be empty' });
+
+      return;
+    }
+
+    room.name = name.trim();
+
+    broadcastRoomList();
+
+    broadcast(roomId, 'room_renamed', { roomId, name: room.name });
+  },
+
+  join_room(ws, { roomId }) {
+    const room = rooms.get(roomId);
+    const client = clients.get(ws);
+
+    if (!room) {
+      send(ws, 'error', { message: 'Room not found.' });
+
+      return;
+    }
+
+    if (!client.username) {
+      send(ws, 'error', { message: 'Set a username first' });
+
+      return;
+    }
+
+    client.roomId = roomId;
+
+    send(ws, 'room_joined', {
+      room: { id: room.id, name: room.name },
+      messages: room.messages,
+    });
+
+    broadcast(roomId, 'user_joined', { username: client.username }, ws);
+  },
+
+  delete_room(ws, { roomId }) {
+    if (!rooms.has(roomId)) {
+      send(ws, 'error', { message: 'Room not found.' });
+
+      return;
+    }
+
+    rooms.delete(roomId);
+
+    // Move everyone in that room out
+    for (const [clientWs, client] of clients) {
+      if (client.roomId === roomId) {
+        client.roomId = null;
+        send(clientWs, 'room_deleted', { roomId });
+      }
+    }
+
+    broadcastRoomList();
+  },
+
+  send_message(ws, { text }) {
+    const client = clients.get(ws);
+
+    if (!client.roomId) {
+      send(ws, 'error', { message: 'Join a room first.' });
+
+      return;
+    }
+
+    if (!text || !text.trim()) {
+      send(ws, 'error', { message: 'Message cannot be empty.' });
+
+      return;
+    }
+
+    const room = rooms.get(client.roomId);
+
+    if (!room) {
+      send(ws, 'error', { message: 'Room not found.' });
+
+      return;
+    }
+
+    const message = {
+      id: Date.now(),
+      author: client.username,
+      text: text.trim(),
+      time: new Date().toISOString(),
+    };
+
+    room.messages.push(message);
+    broadcast(client.roomId, 'new_message', { message });
+  },
+};
+
+// ─── WebSocket server ────────────────────────────────────────────────────────
+
+const wss = new WebSocketServer({ server });
+
+wss.on('connection', (ws) => {
+  clients.set(ws, { username: null, roomId: null });
+
+  ws.on('message', (raw) => {
+    let parsed;
+
+    try {
+      parsed = JSON.parse(raw);
+    } catch {
+      send(ws, 'error', { message: 'Invalid JSON.' });
+
+      return;
+    }
+
+    const { type, ...payload } = parsed;
+    const handler = handlers[type];
+
+    if (handler) {
+      handler(ws, payload);
+    } else {
+      send(ws, 'error', { message: `Unknown message type: ${type}` });
+    }
+  });
+
+  ws.on('close', () => {
+    const client = clients.get(ws);
+
+    if (client && client.roomId && client.username) {
+      broadcast(client.roomId, 'user_left', { username: client.username });
+    }
+
+    clients.delete(ws);
+  });
+});
+
+// ─── Start ───────────────────────────────────────────────────────────────────
+
+server.listen(PORT, () => {
+  // eslint-disable-next-line
+  console.log(`Chat server running at http://localhost:${PORT}`);
+});

src/public/.eslintrc.js

@@ -0,0 +1,5 @@
+module.exports = {
+  env: {
+    browser: true,
+  },
+};