import SwiftUI
import Combine
import FirebaseCore
import FirebaseMessaging

@main
struct DebugNotificationApp: App {
    
#if os(iOS)
    @UIApplicationDelegateAdaptor(AppDelegate.self) var delegate
#elseif os(watchOS)
    @WKApplicationDelegateAdaptor(AppDelegate.self) var delegate
#endif
    
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

struct ContentView: View {
    @EnvironmentObject var delegate: AppDelegate
    var body: some View {
        if let currentFCMToken = self.delegate.currentFCMToken {
            Text(currentFCMToken)
            ShareLink(item: currentFCMToken)
        } else {
            Text("No FCM token")
        }
    }
}

@MainActor
class AppDelegate: NSObject, ObservableObject, MessagingDelegate, UNUserNotificationCenterDelegate {
    
    @Published var currentFCMToken: String?
    
    func messaging(_ messaging: Messaging, didReceiveRegistrationToken fcmToken: String?) {
        print("==== ↓ Firebase Cloud Messaging token ↓ ====\n\(fcmToken!)")
        self.currentFCMToken = fcmToken
    }
    
    func setUpNotification() {
        Task {
            let notificationCenter = UNUserNotificationCenter.current()
            try! await notificationCenter.requestAuthorization(options: [.alert, .sound])
            notificationCenter.delegate = self
        }
    }
}

#if os(iOS)
extension AppDelegate: UIApplicationDelegate {
    func application(_ application: UIApplication,
                     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        FirebaseApp.configure()
        Messaging.messaging().delegate = self
        
        self.setUpNotification()
        application.registerForRemoteNotifications()
        return true
    }
    
    func application(_ application: UIApplication,
                     didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {}
}
#elseif os(watchOS)
extension AppDelegate: WKApplicationDelegate {
    func applicationDidFinishLaunching() {
        FirebaseApp.configure()
        Messaging.messaging().delegate = self
        
        self.setUpNotification()
        WKApplication.shared().registerForRemoteNotifications()
    }
    
    func didRegisterForRemoteNotifications(withDeviceToken deviceToken: Data) {
        Messaging.messaging().apnsToken = deviceToken
    }
}
#endif