Here App Region Monitoring and Notification Trigger Logic

regionMonitoring.swift

  // MARK: - Significant location change montioring logic

  // Called at launch of application if permission is already granted
  func startMonitoringSignificantLocationChanges() {
    locationManager.startMonitoringSignificantLocationChanges()
  }

  // Called by location manager if there is a significant location change
  func locationManager(_ manager: CLLocationManager,
                       didUpdateLocations locations: [CLLocation]) {
    guard let latestLocation = locations.last else {
      // No location found
      return
    }
    self.latestLocation = latestLocation
    self.updateTrackedPlaces(coordinate: latestLocation.coordinate)
  }

  func updateTrackedPlaces(coordinate: CLLocationCoordinate2D) {
    // Fetches new places
    dataStore.retrievePlaces(latitude: coordinate.latitude, longitude: coordinate.longitude) { [unowned self] (success, data, count) in
      if self.authorized {
        // Track the new places
        self.trackPlaces(places: data)
      }
    }
  }

  func trackPlaces(places: [Place]) {
    // Removes all the currently monitored regions
    self.removeAllMonitoredRegions()
    // Saves the new places in our place data store
    PlaceManager.shared.savePlaces(places: places)
    for place in places {
      // Starts monitoring the new places
      self.locationManager.startMonitoring(for: place.region())
    }
  }

  // MARK: - Region montioring logic

  func locationManager(_ manager: CLLocationManager, didEnterRegion region: CLRegion) {
    guard let region = region as? CLCircularRegion else {
      // region type was not valid
      return
    }

    enteredRegion(region)
  }

  func enteredRegion(_ region: CLCircularRegion) {
    if !canTriggerNotification(for: region) {
      return
    }

    let identifier = region.identifier
    // Retrieve place from data store
    guard let place = PlaceManager.shared.placeForIdentifier(identifier) else {
      // Could not find place with that identifier
      return
    }

    triggerNotificationForPlace(place)
  }