mate-academy · DimasSavchenko · Apr 9, 2026 · Apr 14, 2026 · mateacademy-ai-mentor · Apr 9, 2026
diff --git a/.gitignore b/.gitignore
@@ -5,5 +5,8 @@
 # Node
 node_modules
 
+# Build
+client/dist
+
 # MacOS
 .DS_Store
diff --git a/client/index.html b/client/index.html
@@ -0,0 +1,12 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Node Chat</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.jsx"></script>
+  </body>
+</html>
diff --git a/client/src/App.jsx b/client/src/App.jsx
@@ -0,0 +1,331 @@
+import { useEffect, useMemo, useRef, useState } from 'react';
+import { io } from 'socket.io-client';
+
+const socket = io('http://localhost:3005');
+const USERNAME_KEY = 'node_chat_username';
+
+export default function App() {
+  const [username, setUsername] = useState(
+    localStorage.getItem(USERNAME_KEY) || '',
+  );
+  const [draftUsername, setDraftUsername] = useState(username);
+  const [rooms, setRooms] = useState([]);
+  const [currentRoom, setCurrentRoom] = useState(null);
+  const [messages, setMessages] = useState([]);
+  const [messageText, setMessageText] = useState('');
+  const [newRoomName, setNewRoomName] = useState('');
+  const [renameValue, setRenameValue] = useState('');
+  const [error, setError] = useState('');
+  const [toast, setToast] = useState(null);
+  const messageEndRef = useRef(null);
+
+  const showToast = (message, type = 'info') => {
+    setToast({ message, type });
+  };
+
+  useEffect(() => {
+    socket.on('roomList', setRooms);
+    socket.on('roomJoined', (room) => {
+      setCurrentRoom({ id: room.id, name: room.name });
+      setMessages(room.messages || []);
+      setRenameValue(room.name);
+    });
+    socket.on('roomCreated', (roomId) => {
+      showToast('Room created', 'success');
+      joinRoom(roomId);
+    });
+    socket.on('newMessage', (message) => {
+      setMessages((prev) => [...prev, message]);
+    });
+    socket.on('systemMessage', (message) => {
+      setMessages((prev) => [...prev, message]);
+    });
+    socket.on('roomRenamed', (room) => {
+      setCurrentRoom((prev) => (prev && prev.id === room.id ? room : prev));
+      setRenameValue(room.name);
+    });
+    socket.on('roomDeleted', (roomId) => {
+      setRooms((prev) => prev.filter((room) => room.id !== roomId));
+      setCurrentRoom((prev) => (prev?.id === roomId ? null : prev));
+      setMessages((prev) =>
+        prev.concat({
+          author: 'System',
+          text: 'Current room was deleted',
+          time: new Date().toISOString(),
+        }),
+      );
+      showToast('Room deleted', 'warning');
+    });
+    socket.on('error', (message) => {
+      setError(message);
+      showToast(message, 'error');
+    });
+
+    return () => {
+      socket.off('roomList');
+      socket.off('roomJoined');
+      socket.off('roomCreated');
+      socket.off('newMessage');
+      socket.off('systemMessage');
+      socket.off('roomRenamed');
+      socket.off('roomDeleted');
+      socket.off('error');
+    };
+  }, []);
+
+  useEffect(() => {
+    if (username) {
+      socket.emit('setUsername', username);
+    }
+  }, [username]);
+
+  useEffect(() => {
+    messageEndRef.current?.scrollIntoView({ behavior: 'smooth' });
+  }, [messages]);
+
+  useEffect(() => {
+    if (!toast) {
+      return;
+    }
+
+    const id = setTimeout(() => {
+      setToast(null);
+    }, 3000);
+
+    return () => clearTimeout(id);
+  }, [toast]);
+
+  const roomName = useMemo(() => {
+    if (!currentRoom) {
+      return 'No room selected';
+    }
+
+    return currentRoom.name;
+  }, [currentRoom]);
+
+  const saveUsername = (event) => {
+    event.preventDefault();
+
+    const cleaned = draftUsername.trim();
+
+    if (!cleaned) {
+      setError('Username is required');
+
+      return;
+    }
+
+    setError('');
+    localStorage.setItem(USERNAME_KEY, cleaned);
+    setUsername(cleaned);
+  };
+
+  const joinRoom = (roomId) => {
+    setError('');
+    socket.emit('joinRoom', roomId);
+  };
+
+  const sendMessage = (event) => {
+    event.preventDefault();
+
+    const cleaned = messageText.trim();
+
+    if (!cleaned || !currentRoom) {
+      return;
+    }
+
+    socket.emit('sendMessage', cleaned);
+    setMessageText('');
+  };
+
+  const createRoom = (event) => {
+    event.preventDefault();
+    const cleaned = newRoomName.trim();
+
+    if (!cleaned) {
+      return;
+    }
+
+    if (rooms.some((r) => r.name === cleaned)) {
+      showToast('Room already exists', 'warning');
+      return;
+    }
+
+    socket.emit('createRoom', cleaned, (response) => {
+      if (!response?.ok) {
+        const message = response?.error || 'Failed to create room';
+        setError(message);
+        showToast(message, 'error');
+        return;
+      }
+
+      showToast('Room created', 'success');
+      joinRoom(response.roomId);
+    });
+
+    setNewRoomName('');
+    showToast('Creating room...', 'info');
+  };
+
+  const renameRoom = (event) => {
+    event.preventDefault();
+
+    if (!currentRoom) {
+      return;
+    }
+
+    const cleaned = renameValue.trim();
+
+    if (!cleaned) {
+      return;
+    }
+
+    if (rooms.some((r) => r.name === cleaned)) {
+      showToast('Room already exists', 'warning');
+      return;
+    }
+
+    socket.emit('renameRoom', { roomId: currentRoom.id, newName: cleaned });
+    showToast('Room renamed', 'success');
+  };
+
+  const deleteRoom = () => {
+    if (!currentRoom) {
+      return;
+    }
+
+    socket.emit('deleteRoom', currentRoom.id);
+    showToast('Room delete requested', 'warning');
+  };
+
+  const resetUsername = () => {
+    localStorage.removeItem(USERNAME_KEY);
+    setUsername('');
+    setDraftUsername('');
+    setCurrentRoom(null);
+    setMessages([]);
+    setError('');
+  };
+
+  if (!username) {
+    return (
+      <main className="auth-screen">
+        <form onSubmit={saveUsername} className="auth-card">
+          <h1>Welcome to Node Chat</h1>
+          <p>Create your username to continue</p>
+          <label htmlFor="username">Username</label>
+          <input
+            id="username"
+            value={draftUsername}
+            onChange={(e) => setDraftUsername(e.target.value)}
+            placeholder="Enter username"
+            autoFocus
+          />
+          <button type="submit">Continue</button>
+          {error && <div className="error">{error}</div>}
+        </form>
+      </main>
+    );
+  }
+
+  return (
+    <>
+      {toast && (
+        <div className={`toast toast-${toast.type}`}>{toast.message}</div>
+      )}
+      <div className="layout">
+        <aside className="sidebar">
+          <h2>Rooms</h2>
+
+          <div className="panel">
+            <strong>{username}</strong>
+            <button type="button" onClick={resetUsername}>
+              Change user
+            </button>
+          </div>
+
+          <form onSubmit={createRoom} className="panel">
+            <label htmlFor="new-room">Create Room</label>
+            <input
+              id="new-room"
+              value={newRoomName}
+              onChange={(e) => setNewRoomName(e.target.value)}
+              placeholder="Room name"
+            />
+            <button type="submit">Create</button>
+          </form>
+
+          <div className="rooms-list">
+            {rooms.map((room) => (
+              <button
+                key={room.id}
+                type="button"
+                className={`room-button ${currentRoom?.id === room.id ? 'active' : ''}`}
+                onClick={() => joinRoom(room.id)}
+              >
+                {room.name}
+              </button>
+            ))}
+          </div>
+        </aside>
+
+        <main className="chat">
+          <header className="chat-header">
+            <div>
+              <h1>{roomName}</h1>
+              <p>
+                {username
+                  ? `Signed in as ${username}`
+                  : 'Set username to start'}
+              </p>
+            </div>
+
+            {currentRoom && (
+              <div className="room-actions">
+                <form onSubmit={renameRoom}>
+                  <input
+                    value={renameValue}
+                    onChange={(e) => setRenameValue(e.target.value)}
+                    placeholder="New room name"
+                  />
+                  <button type="submit">Rename</button>
+                </form>
+                <button type="button" className="danger" onClick={deleteRoom}>
+                  Delete
+                </button>
+              </div>
+            )}
+          </header>
+
+          {error && <p className="error">{error}</p>}
+
+          <section className="messages">
+            {messages.map((message, index) => (
+              <article key={`${message.time}-${index}`} className="message">
+                <div className="meta">
+                  <strong>{message.author}</strong>
+                  <time>{new Date(message.time).toLocaleTimeString()}</time>
+                </div>
+                <p>{message.text}</p>
+              </article>
+            ))}
+            <div ref={messageEndRef} />
+          </section>
+
+          <form onSubmit={sendMessage} className="send-form">
+            <input
+              value={messageText}
+              onChange={(e) => setMessageText(e.target.value)}
+              placeholder={
+                currentRoom ? 'Write a message' : 'Join a room first'
+              }
+              disabled={!currentRoom || !username}
+            />
+            <button type="submit" disabled={!currentRoom || !username}>
+              Send
+            </button>
+          </form>
+        </main>
+      </div>
+    </>
+  );
+}
diff --git a/client/src/main.jsx b/client/src/main.jsx
@@ -0,0 +1,10 @@
+import React from 'react';
+import { createRoot } from 'react-dom/client';
+import App from './App';
+import './styles.css';
+
+createRoot(document.getElementById('root')).render(
+  <React.StrictMode>
+    <App />
+  </React.StrictMode>,
+);