# Polly - P2P Poll App

A lightweight, real-time collaborative polling application that uses [Yjs](https://yjs.dev/) and [WebRTC](https://de.wikipedia.org/wiki/WebRTC) to allow multiple users to create options, vote, and see live results without a centralized database or back-end server.

### 🚀 Features

- Real-time Collaboration: Instant synchronization of poll titles, options, and votes across all connected peers using [CRDTs (Conflict-free Replicated Data Types)](https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type).
- P2P Connectivity: Uses WebRTC via [y-webrtc](https://github.com/yjs/y-webrtc) for direct browser-to-browser communication.
- Dynamic Voting: * Add new options on the fly.
    - Live-updating progress bars and vote tallies.
    - Automatic sorting of options by vote count.
- Voting Deadline: A shared countdown timer (2 minutes) that locks the poll for all participants once expired.
- Awareness & Presence: A status bar showing connection health and the number of active peers currently in the room.
- Local Persistence: Uses [y-indexeddb](https://github.com/yjs/y-indexeddb) to save the poll state locally in your browser, ensuring data isn't lost if you refresh or lose connection.
- No Setup Required: Unique "rooms" are created via URL parameters, making it easy to share a link and start a poll instantly.

### 🛠 Tech Stack

- Language: TypeScript
- State Management: Yjs (Shared data types: Y.Doc, Y.Map, Y.Text)
- Networking: y-webrtc (WebRTC provider for Yjs)
- UI: Vanilla DOM manipulation (No heavy frameworks like React or Vue)

### 💡 How It Works

- Room Creation: When you open the app, it checks for a ?room= parameter. If none exists, it generates a unique ID and updates the URL.
- State Synchronization: The y-webrtc provider connects users with the same room ID. Any change to sync.options or sync.votes is propagated to all users.
- Local Reactivity: Components use .observe() and .observeDeep() on Yjs types to trigger a re-render of the UI whenever the shared state changes.
- Voting: Votes are stored in a Y.Map<string> where the key is the User ID and the value is the Option ID. This ensures each user can only have one active vote at a time.

You can simulate a second user by opening an incognito Tab.

### 🔧 Installation, Development and Deployment

- Install dependencies:

    ```npm install yjs y-webrtc y-indexeddb```

- Development:
    
    ```npm run dev```

- Deployment:
    - The code currently uses an Y-Webrtc-Signaling-Server at localhost:4444 that starts with `npm run dev` for development.
    - To deploy the App, you need to set up a publicly available signaling server and set the address in the `synx.ts`. E.g. with Docker using the [funnyzak/y-webrtc-signaling](https://hub.docker.com/r/funnyzak/y-webrtc-signaling) image:

        ```version: '3.1'
        services:
            y-webrtc-signaling:
                container_name: y-webrtc-signaling
                image: funnyzak/y-webrtc-signaling:latest
                restart: always
                network_mode: bridge
                ports:
                - "4444:4444"
                dns: 8.8.8.8```