Solution

src/index.js

@@ -1 +1,156 @@
 'use strict';
+
+const http = require('http');
+const fs = require('fs');
+const path = require('path');
+const { Server } = require('socket.io');
+
+const PORT = process.env.PORT || 3001;
+const PUBLIC_DIR = path.join(__dirname, 'public');
+
+const rooms = new Map();
+const DEFAULT_ROOM = 'general';
+
+rooms.set(DEFAULT_ROOM, {
+  id: DEFAULT_ROOM,
+  name: 'General',
+  messages: [],
+});
+
+function createRoom(id, roomName) {
+  const room = { id, name: roomName, messages: [] };
+
+  rooms.set(id, room);
+
+  return room;
+}
+
+function getRoomsData() {
+  return Array.from(rooms.values()).map((room) => ({
+    id: room.id,
+    name: room.name,
+  }));
+}
+
+const server = http.createServer((req, res) => {
+  const filePath = path.join(
+    PUBLIC_DIR,
+    req.url === '/' ? 'index.html' : req.url,
+  );
+
+  const ext = path.extname(filePath);
+  const contentTypes = {
+    '.html': 'text/html',
+    '.js': 'application/javascript',
+    '.jsx': 'application/javascript',
+    '.css': 'text/css',
+  };
+
+  const contentType = contentTypes[ext] || 'text/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);
+  });
+});
+
+const io = new Server(server);
+
+io.on('connection', (socket) => {
+  let currentRoom = null;
+  let username = null;
+
+  socket.emit('rooms:list', getRoomsData());
+
+  socket.on('user:set', (userName) => {
+    username = userName;
+  });
+
+  socket.on('room:join', (roomId) => {
+    if (!rooms.has(roomId)) {
+      socket.emit('error', `Room "${roomId}" does not exist`);
+
+      return;
+    }
+
+    if (currentRoom) {
+      socket.leave(currentRoom);
+    }
+
+    currentRoom = roomId;
+    socket.join(roomId);
+
+    const room = rooms.get(roomId);
+
+    socket.emit('room:history', { roomId, messages: room.messages });
+  });
+
+  socket.on('room:create', ({ id, name: roomName }) => {
+    if (rooms.has(id)) {
+      socket.emit('error', `Room "${id}" already exists`);
+
+      return;
+    }
+
+    const room = createRoom(id, roomName);
+
+    io.emit('rooms:list', getRoomsData());
+    socket.emit('room:created', { id: room.id, name: room.name });
+  });
+
+  socket.on('room:rename', ({ id, name: newName }) => {
+    if (!rooms.has(id)) {
+      socket.emit('error', `Room "${id}" does not exist`);
+
+      return;
+    }
+
+    rooms.get(id).name = newName;
+    io.emit('rooms:list', getRoomsData());
+  });
+
+  socket.on('room:delete', (id) => {
+    if (id === DEFAULT_ROOM) {
+      socket.emit('error', 'Cannot delete the default room');
+
+      return;
+    }
+
+    if (!rooms.has(id)) {
+      socket.emit('error', `Room "${id}" does not exist`);
+
+      return;
+    }
+
+    rooms.delete(id);
+    io.emit('rooms:list', getRoomsData());
+    io.to(id).emit('room:deleted', id);
+  });
+
+  socket.on('message:send', ({ roomId, text }) => {
+    if (!rooms.has(roomId)) {
+      return;
+    }
+
+    const message = {
+      id: Date.now() + Math.random().toString(36).slice(2),
+      author: username || 'Anonymous',
+      text,
+      time: new Date().toISOString(),
+    };
+
+    rooms.get(roomId).messages.push(message);
+    io.to(roomId).emit('message:new', { roomId, message });
+  });
+});
+
+server.listen(PORT, () => {
+  // eslint-disable-next-line no-console
+  console.log(`Chat server running at http://localhost:${PORT}`);
+});