iOS Collector

The LightChallenge iOS app collects Apple Health evidence (steps and walking/running distance) and submits it to the backend for verification.

Overview

The iOS collector is a lightweight SwiftUI app that:

1. Reads HealthKit data (step count, walking + running distance)
2. Packages it as a JSON evidence payload
3. Submits it to the /api/aivm/intake endpoint
4. Authenticates via a signed evidence token from the webapp

Requirements

• Xcode 15+
• iOS 17+ device (HealthKit requires a physical device)
• Apple Developer account (free tier works for personal testing)

Setup

1. Open the Project

open mobile/ios/LightChallengeApp/LightChallengeApp.xcodeproj

2. Configure Server URL

Edit Sources/Models/Models.swift and set the server URL for your environment:

• UAT (default): https://uat.lightchallenge.app
• Production: https://app.lightchallenge.app
• Local dev: Replace YOUR_MAC_IP with your Mac’s LAN IP address

3. Signing

In Xcode:

1. Select the project in the navigator
2. Go to Signing & Capabilities
3. Select your personal team
4. Let Xcode manage signing automatically

4. Build and Run

Select your iPhone as the target device and press Cmd+R.

Usage Flow

Full Authenticated Flow (Recommended)

1. Open the webapp in a browser and connect your wallet
2. Navigate to a challenge’s proof page
3. Select “Apple Health” as the evidence source
4. Click “Sign & Generate QR” — this signs a one-time token with your wallet
5. Scan the QR code with your iPhone camera
6. The app opens via deep link with the auth token pre-filled
7. Grant HealthKit permissions when prompted
8. Tap “Collect Health Data” then “Submit Evidence”

How Authentication Works

The webapp generates an EIP-191 signed message:

lightchallenge-evidence:{challengeId}:{subject}:{expires}

This signature is embedded in the deep link URL and sent with the evidence submission. The server recovers the signer and verifies it matches the wallet address.

HealthKit Permissions

The app requests read-only access to:

• HKQuantityType(.stepCount) — Daily step counts
• HKQuantityType(.distanceWalkingRunning) — Walking and running distance

No write permissions are requested. No clinical health records are accessed.

Deep Link Format

lightchallenge://challenge/{id}?subject={wallet}&token={signature}&expires={timestamp}

Troubleshooting