//
//  FeelsApp.swift
//  Shared
//
//  Created by Trey Tartt on 1/5/22.
//

import SwiftUI
import BackgroundTasks

@main
struct FeelsApp: App {
    @Environment(\.scenePhase) private var scenePhase
    let persistenceController = PersistenceController.shared
    
    init() {
//        persistenceController.fillInMissingDates()
        
        BGTaskScheduler.shared.cancelAllTaskRequests()
        BGTaskScheduler.shared.register(forTaskWithIdentifier: BGTask.updateDBMissingID, using: nil) { (task) in
            BGTask.runFillInMissingDatesTask(task: task as! BGProcessingTask)
        }
    }
    
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environment(\.managedObjectContext, persistenceController.container.viewContext)
        }.onChange(of: scenePhase) { phase in
            if phase == .background {
                BGTask.scheduleBackgroundProcessing()
                print("background")
            }
        }
    }
}

class BGTask {
    static let updateDBMissingID = "com.88oak.dbUpdateMissing"
    
    class func runFillInMissingDatesTask(task: BGProcessingTask) {
        BGTask.scheduleBackgroundProcessing()
        
        task.expirationHandler = {
            task.setTaskCompleted(success: false)
        }
        
        PersistenceController.shared.fillInMissingDates()
        task.setTaskCompleted(success: true)
    }
    
    @available(iOS 13.0, *)
    class func scheduleBackgroundProcessing() {
        let request = BGProcessingTaskRequest(identifier: BGTask.updateDBMissingID)
        request.requiresNetworkConnectivity = false
        request.requiresExternalPower = false
        
        var runDate = Calendar.current.date(byAdding: .day, value: 1, to: Date())
        runDate = Calendar.current.date(bySettingHour: 0, minute: 1, second: 0, of: runDate!)
        request.earliestBeginDate = runDate
        
        do {
            try BGTaskScheduler.shared.submit(request)
        } catch {
            print("Could not schedule image fetch: (error)")
        }
    }
}