# Run+ Sync (MVP)

This is a minimal SwiftUI + MultipeerConnectivity prototype to sync **local MP3 playback** across iPhones. One device hosts and controls playback; peers join, receive the track file, and then sync playback.

## Setup (Xcode)
1. Create a new iOS App project in Xcode (SwiftUI, iOS 17+ or latest).
2. Replace the generated Swift files with the files in `RunPlus/`.
3. Add these keys to your app's `Info.plist`:
   - `NSLocalNetworkUsageDescription` = "Sync audio with nearby runners"
   - `NSBonjourServices` (Array) with `_runplus-sync._tcp`
   - `NSBluetoothAlwaysUsageDescription` = "Find nearby runners"

## How It Works
- Host taps **Host**, peers tap **Join**.
- Host imports an MP3 via **Import MP3**, then taps **Send Track** to push it to peers.
- Host taps **Play** to broadcast a shared start time.
- Host can tap **Sync Now** for a quick clock sync.

## Notes
- This is a prototype using `AVAudioEngine` host-time scheduling plus uptime-based sync. It is good enough for group runs, but not sample-accurate.