iOS Remote Notification

AppDelegate.swift

import UIKit
import Firebase
import UserNotifications

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

  var window: UIWindow?
  static var shared: AppDelegate { return UIApplication.shared.delegate as! AppDelegate }

  func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    FirebaseApp.configure()
    application.registerForRemoteNotifications()
    requestNotificationAuthorization(application: application)
    if let userInfo = launchOptions?[UIApplicationLaunchOptionsKey.remoteNotification] {
      NSLog("[RemoteNotification] applicationState: \(applicationStateString) didFinishLaunchingWithOptions for iOS9: \(userInfo)")
      //TODO: Handle background notification
    }
    return true
  }
  
  var applicationStateString: String {
    if UIApplication.shared.applicationState == .active {
      return "active"
    } else if UIApplication.shared.applicationState == .background {
      return "background"
    }else {
      return "inactive"
    }
  }
  
  func requestNotificationAuthorization(application: UIApplication) {
    if #available(iOS 10.0, *) {
      UNUserNotificationCenter.current().delegate = self
      let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
      UNUserNotificationCenter.current().requestAuthorization(options: authOptions, completionHandler: {_, _ in })
    } else {
      let settings: UIUserNotificationSettings = UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil)
      application.registerUserNotificationSettings(settings)
    }
  }
}

@available(iOS 10, *)
extension AppDelegate : UNUserNotificationCenterDelegate {
  // iOS10+, called when presenting notification in foreground
  func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
    let userInfo = notification.request.content.userInfo
    NSLog("[UserNotificationCenter] applicationState: \(applicationStateString) willPresentNotification: \(userInfo)")
    //TODO: Handle foreground notification
    completionHandler([.alert])
  }
  
  // iOS10+, called when received response (default open, dismiss or custom action) for a notification
  func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
    let userInfo = response.notification.request.content.userInfo
    NSLog("[UserNotificationCenter] applicationState: \(applicationStateString) didReceiveResponse: \(userInfo)")
    //TODO: Handle background notification
    completionHandler()
  }
}

extension AppDelegate : MessagingDelegate {
  func messaging(_ messaging: Messaging, didRefreshRegistrationToken fcmToken: String) {
    NSLog("[RemoteNotification] didRefreshRegistrationToken: \(fcmToken)")
  }
  
  // iOS9, called when presenting notification in foreground
  func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any]) {
    NSLog("[RemoteNotification] applicationState: \(applicationStateString) didReceiveRemoteNotification for iOS9: \(userInfo)")
    if UIApplication.shared.applicationState == .active {
      //TODO: Handle foreground notification
    } else {
      //TODO: Handle background notification
    }
  }
}