import HealthKit

class HealthKitService: ObservableObject {
    let healthStore = HKHealthStore()
    var isAvailable: Bool { HKHealthStore.isHealthDataAvailable() }

    func requestAuthorization() async throws {
        let typesToRead: Set<HKObjectType> = [
            HKQuantityType(.heartRate),
            HKQuantityType(.restingHeartRate),
            HKQuantityType(.heartRateVariabilitySDNN),
            HKQuantityType(.stepCount),
            HKQuantityType(.activeEnergyBurned),
            HKQuantityType(.oxygenSaturation),
            HKCategoryType(.sleepAnalysis),
        ]
        try await healthStore.requestAuthorization(toShare: [], read: typesToRead)
    }

    func fetchTodaySteps() async -> Int {
        guard let type = HKQuantityType.quantityType(forIdentifier: .stepCount) else { return 0 }
        let now = Date()
        let startOfDay = Calendar.current.startOfDay(for: now)
        let predicate = HKQuery.predicateForSamples(withStart: startOfDay, end: now)
        return await withCheckedContinuation { cont in
            let q = HKStatisticsQuery(quantityType: type, quantitySamplePredicate: predicate, options: .cumulativeSum) { _, result, _ in
                cont.resume(returning: Int(result?.sumQuantity()?.doubleValue(for: .count()) ?? 0))
            }
            healthStore.execute(q)
        }
    }
}