// Copyright 2020 Google LLC. All rights reserved.
//
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this
// file except in compliance with the License. You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under
// the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
// ANY KIND, either express or implied. See the License for the specific language governing
// permissions and limitations under the License.

import GoogleMaps
import UIKit

class MyLocationViewController: UIViewController {

  private let cameraLatitude: CLLocationDegrees = -33.868

  private let cameraLongitude: CLLocationDegrees = 151.2086

  private let cameraZoom: Float = 12

  lazy var mapView: GMSMapView = {
    let camera = GMSCameraPosition(
      latitude: cameraLatitude, longitude: cameraLongitude, zoom: cameraZoom)
    return GMSMapView(frame: .zero, camera: camera)
  }()

  var observation: NSKeyValueObservation?
  var location: CLLocation? {
    didSet {
      guard oldValue == nil, let firstLocation = location else { return }
      mapView.camera = GMSCameraPosition(target: firstLocation.coordinate, zoom: 14)
    }
  }

  override func viewDidLoad() {
    super.viewDidLoad()

    mapView.delegate = self
    mapView.settings.compassButton = true
    mapView.settings.myLocationButton = true
    mapView.isMyLocationEnabled = true
    view = mapView

    // Listen to the myLocation property of GMSMapView.
    observation = mapView.observe(\.myLocation, options: [.new]) {
      [weak self] mapView, _ in
      self?.location = mapView.myLocation
    }
  }

  deinit {
    observation?.invalidate()
  }
}

extension MyLocationViewController: GMSMapViewDelegate {
  func mapView(_ mapView: GMSMapView, didTapMyLocation location: CLLocationCoordinate2D) {
    let alert = UIAlertController(
      title: "Location Tapped",
      message: "Current location: <\(location.latitude), \(location.longitude)>",
      preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "OK", style: .default))
    present(alert, animated: true)
  }
}