class HealthKitManager: ObservableObject {
  func requestAuthorization() async throws {
    guard HKHealthStore.isHealthDataAvailable() else {
      throw HealthKitError.notAvailable
    }
    
    let types: Set<HKObjectType> = [
      .workoutType(),
      .quantityType(forIdentifier: .heartRate)!
    ]
    
    try await healthStore.requestAuthorization(toShare: [], read: types)
  }
}

class WorkoutViewModel: ObservableObject {
  @Published var workouts: [Workout] = []
  
  func fetchWorkouts() {
    healthKitManager.fetchWorkouts { [weak self] result in
      DispatchQueue.main.async {
        self?.workouts = result
      }
    }
  }
}