mbt1.swift

import UIKit
import BackgroundTasks

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        BGTaskScheduler.shared.register(
            forTaskWithIdentifier: "pl.snowdog.example.refresh",
            using: DispatchQueue.global()
        ) { task in
            self.handleAppRefresh(task)
        }
        return true
    }

    private func handleAppRefresh(_ task: BGTask) {
        let queue = OperationQueue()
        queue.maxConcurrentOperationCount = 1
        let appRefreshOperation = AppRefreshOperation()
        queue.addOperation(appRefreshOperation)

        task.expirationHandler = {
            queue.cancelAllOperations()
        }

        let lastOperation = queue.operations.last
        lastOperation?.completionBlock = {
            task.setTaskCompleted(success: !(lastOperation?.isCancelled ?? false))
        }

        scheduleAppRefresh()
    }
}