feat: implement dynamic P2P polling app with real-time synchronization

- Add complete P2P polling application with React + TypeScript frontend - Implement Node.js backend with Yjs WebSocket and WebRTC signaling - Support dynamic poll creation, answer management, and voting - Add CRDT-based state synchronization using Yjs for conflict-free merging - Implement user tracking and vote prevention (one vote per user per option) - Create modern UI with Tailwind CSS and visual feedback - Add comprehensive documentation and setup instructions Features: - Users can create polls with custom questions - Anyone can add answer options to any poll - Real-time voting with instant cross-client synchronization - Smart vote tracking with visual feedback for voted options - User attribution showing who created polls and options - Connection status indicators for WebSocket and P2P connections Technical: - Hybrid P2P architecture (WebSocket + WebRTC) - CRDT-based state management with Yjs
2026-03-25 11:51:33 +01:00
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-# P2P Poll App
+# P2P Poll App
+
+A peer-to-peer polling application built with React, TypeScript, Tailwind CSS, Node.js, Yjs, and WebSocket for real-time collaborative voting.
+
+**Users can create polls, add answers, and vote in real-time with automatic P2P synchronization across all connected clients.**
+
+## Architecture
+
+**Hybrid P2P Approach:**
+- Backend serves as both a Yjs WebSocket provider (for state synchronization) and signaling server (for WebRTC peer discovery)
+- Clients sync poll data via Yjs CRDT for conflict-free merging
+- Direct P2P connections via WebRTC for real-time updates when possible
+- Server fallback ensures reliability when P2P fails
+
+## Tech Stack
+
+**Backend:**
+- Node.js + TypeScript
+- Express.js
+- WebSocket (ws)
+- y-websocket (Yjs WebSocket provider)
+- CORS support
+
+**Frontend:**
+- React 18 + TypeScript
+- Vite (build tool)
+- Tailwind CSS
+- Yjs (CRDT library)
+- y-websocket (server sync)
+- y-webrtc (P2P sync)
+- lucide-react (icons)
+
+## Project Structure
+
+```
+quicgroup/
+├── server/                 # Backend Node.js server
+│   ├── src/
+│   │   ├── index.ts       # Main server entry
+│   │   ├── yjs-server.ts  # Yjs WebSocket provider
+│   │   ├── signaling-server.ts  # WebRTC signaling
+│   │   ├── types/         # TypeScript types
+│   │   └── utils/         # Utilities
+│   ├── package.json
+│   └── tsconfig.json
+│
+└── frontend/              # React frontend
+    ├── src/
+    │   ├── components/    # React components
+    │   ├── hooks/         # Custom React hooks
+    │   ├── lib/           # Yjs setup and utilities
+    │   ├── types/         # TypeScript types
+    │   └── styles/        # CSS styles
+    ├── package.json
+    └── vite.config.ts
+```
+
+## Setup Instructions
+
+### Prerequisites
+- Node.js 18+ and npm
+
+### Backend Setup
+
+1. Navigate to server directory:
+```bash
+cd server
+```
+
+2. Install dependencies:
+```bash
+npm install
+```
+
+3. Copy environment file:
+```bash
+cp .env.example .env
+```
+
+4. Start the development server:
+```bash
+npm run dev
+```
+
+The server will run on `http://localhost:3000` with:
+- Yjs WebSocket: `ws://localhost:3000/yjs`
+- Signaling WebSocket: `ws://localhost:3000/signal`
+
+### Frontend Setup
+
+1. Navigate to frontend directory:
+```bash
+cd frontend
+```
+
+2. Install dependencies:
+```bash
+npm install
+```
+
+3. Copy environment file (optional):
+```bash
+cp .env.example .env
+```
+
+4. Start the development server:
+```bash
+npm run dev
+```
+
+The frontend will run on `http://localhost:5173`
+
+## Running the Application
+
+1. **Start Backend** (Terminal 1):
+```bash
+cd server
+npm run dev
+```
+
+2. **Start Frontend** (Terminal 2):
+```bash
+cd frontend
+npm run dev
+```
+
+3. **Open Browser:**
+   - Navigate to `http://localhost:5173`
+   - Open multiple tabs/windows to test P2P synchronization
+
+## Features
+
+### Dynamic Poll Creation
+- **Create Polls** - Any user can create new polls with custom questions
+- **Add Answers** - Anyone can add answer options to any poll
+- **Real-time Voting** - Vote on options with instant updates across all clients
+- **Smart Vote Tracking** - One vote per user per option (prevents duplicate voting)
+- **Visual Feedback** - Green border and " Voted" indicator on voted options
+- **User Attribution** - See who created each poll and option
+- **Live Vote Counts** - See vote percentages and counts update in real-time
+- **P2P Synchronization** - Uses Yjs CRDT for conflict-free state merging
+- **Connection Status** - Visual indicator showing WebSocket and peer connections
+- **Hybrid Architecture** - Combines WebSocket server sync with WebRTC P2P
+- **Beautiful UI** - Modern gradient design with Tailwind CSS
+
+## How to Use
+
+### Create a Poll
+1. Enter your question in the "Create a New Poll" form at the top
+2. Click "Create Poll"
+3. Your poll appears instantly for all connected users
+
+### Add Answer Options
+1. Find the poll you want to add an answer to
+2. Type your answer in the "Add a new option..." field
+3. Click "Add"
+4. Your answer appears instantly for all users
+
+### Vote on Options
+1. Click the vote button (thumbs up icon) on any option
+2. You can only vote once per option
+3. Voted options show a green border and " Voted" indicator
+4. Vote counts update in real-time across all clients
+
+### Multi-User Testing
+1. Open multiple browser tabs/windows
+2. Create polls from different tabs
+3. Add answers from different tabs
+4. Vote from different tabs
+5. Watch real-time synchronization in action!
+
+## How It Works
+
+### CRDT Synchronization
+The app uses Yjs (a CRDT library) to ensure all clients converge to the same state without conflicts:
+- Each client maintains a local Yjs document
+- Changes are automatically synced via WebSocket to the server
+- WebRTC provides direct P2P connections between clients
+- Yjs handles merge conflicts automatically
+- One vote per user per option is enforced via `votedBy` tracking
+
+## Data Model
+```typescript
+{
+  polls: Array<{
+    id: string,
+    question: string,
+    createdBy: string,
+    timestamp: number,
+    options: Array<{
+      id: string,
+      text: string,
+      votes: number,
+      votedBy: string[],  // Tracks which users have voted
+      createdBy: string,
+      timestamp: number
+    }>
+  }>
+}
+```
+
+## Testing P2P Functionality
+
+1. Open the app in multiple browser tabs/windows
+2. **Create polls** from different tabs - they appear everywhere instantly
+3. **Add answer options** from different tabs to the same poll
+4. **Vote** from different tabs - watch vote counts update in real-time
+5. Try voting twice on the same option - it won't let you!
+6. Check the connection status indicator for peer count
+7. Verify visual feedback (green border) on options you've voted on
+
+## Development
+
+### Backend Scripts
+- `npm run dev` - Start development server with hot reload
+- `npm run build` - Build for production
+- `npm start` - Run production build
+
+### Frontend Scripts
+- `npm run dev` - Start Vite dev server
+- `npm run build` - Build for production
+- `npm run preview` - Preview production build
+
+## Environment Variables
+
+### Backend (.env)
+```
+PORT=3000
+YJS_WS_PORT=1234
+NODE_ENV=development
+CORS_ORIGIN=http://localhost:5173
+```
+
+### Frontend (.env)
+```
+VITE_WS_URL=ws://localhost:3000
+```
+
+## Components
+
+### Frontend Components
+- **PollView** - Main view showing all polls and create poll form
+- **CreatePoll** - Form to create new polls
+- **PollCard** - Individual poll display with metadata
+- **OptionList** - List of answer options with vote tracking
+- **AddOption** - Form to add new answer options
+- **VoteButton** - Vote button with disabled state for voted options
+- **ConnectionStatus** - Shows WebSocket and P2P connection status
+
+### Key Functions
+- `createPoll(question)` - Create a new poll
+- `addOption(pollId, text)` - Add an option to a specific poll
+- `vote(pollId, optionId)` - Vote on an option (one vote per user)
+- `hasVoted(option)` - Check if current user has voted on an option
+
+## User Tracking
+
+Each user gets a unique ID stored in localStorage:
+- Format: `user-xxxxxxxxx`
+- Used to track poll/option creators
+- Used to prevent duplicate voting
+- Persists across browser sessions
+
+## Future Enhancements
+
+- [ ] Edit/delete polls and options
+- [ ] User nicknames instead of IDs
+- [ ] Poll expiration/closing
+- [ ] Vote history and analytics
+- [ ] Export poll results
+- [ ] Persistent storage (database)
+- [ ] Dark mode toggle
+- [ ] Mobile responsive improvements
+- [ ] Poll categories/tags
+- [ ] Search/filter polls
+
+## License
+
+MIT