packages/google_maps_flutter/lib/src/controller.dart

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

part of google_maps_flutter;

/// Controller for a single GoogleMap instance running on the host platform.
class GoogleMapController {
  GoogleMapController._(
    this.channel,
    CameraPosition initialCameraPosition,
    this._googleMapState,
  ) : assert(channel != null) {
    channel.setMethodCallHandler(_handleMethodCall);
  }

  static Future<GoogleMapController> init(
    int id,
    CameraPosition initialCameraPosition,
    _GoogleMapState googleMapState,
  ) async {
    assert(id != null);
    final MethodChannel channel =
        MethodChannel('plugins.flutter.io/google_maps_$id');
    await channel.invokeMethod<void>('map#waitForMap');
    return GoogleMapController._(
      channel,
      initialCameraPosition,
      googleMapState,
    );
  }

  @visibleForTesting
  final MethodChannel channel;

  final _GoogleMapState _googleMapState;

  Future<dynamic> _handleMethodCall(MethodCall call) async {
    switch (call.method) {
      case 'camera#onMoveStarted':
        if (_googleMapState.widget.onCameraMoveStarted != null) {
          _googleMapState.widget.onCameraMoveStarted();
        }
        break;
      case 'camera#onMove':
        if (_googleMapState.widget.onCameraMove != null) {
          _googleMapState.widget.onCameraMove(
            CameraPosition.fromMap(call.arguments['position']),
          );
        }
        break;
      case 'camera#onIdle':
        if (_googleMapState.widget.onCameraIdle != null) {
          _googleMapState.widget.onCameraIdle();
        }
        break;
      case 'marker#onTap':
        _googleMapState.onMarkerTap(call.arguments['markerId']);
        break;
      case 'marker#onDragEnd':
        _googleMapState.onMarkerDragEnd(call.arguments['markerId'],
            LatLng._fromJson(call.arguments['position']));
        break;
      case 'infoWindow#onTap':
        _googleMapState.onInfoWindowTap(call.arguments['markerId']);
        break;
      case 'polyline#onTap':
        _googleMapState.onPolylineTap(call.arguments['polylineId']);
        break;
      case 'polygon#onTap':
        _googleMapState.onPolygonTap(call.arguments['polygonId']);
        break;
      case 'circle#onTap':
        _googleMapState.onCircleTap(call.arguments['circleId']);
        break;
      case 'map#onTap':
        _googleMapState.onTap(LatLng._fromJson(call.arguments['position']));
        break;
      case 'map#onLongPress':
        _googleMapState
            .onLongPress(LatLng._fromJson(call.arguments['position']));
        break;
      default:
        throw MissingPluginException();
    }
  }

  /// Updates configuration options of the map user interface.
  ///
  /// Change listeners are notified once the update has been made on the
  /// platform side.
  ///
  /// The returned [Future] completes after listeners have been notified.
  Future<void> _updateMapOptions(Map<String, dynamic> optionsUpdate) async {
    assert(optionsUpdate != null);
    await channel.invokeMethod<void>(
      'map#update',
      <String, dynamic>{
        'options': optionsUpdate,
      },
    );
  }

  /// Updates marker configuration.
  ///
  /// Change listeners are notified once the update has been made on the
  /// platform side.
  ///
  /// The returned [Future] completes after listeners have been notified.
  Future<void> _updateMarkers(_MarkerUpdates markerUpdates) async {
    assert(markerUpdates != null);
    await channel.invokeMethod<void>(
      'markers#update',
      markerUpdates._toMap(),
    );
  }

  /// Updates polygon configuration.
  ///
  /// Change listeners are notified once the update has been made on the
  /// platform side.
  ///
  /// The returned [Future] completes after listeners have been notified.
  Future<void> _updatePolygons(_PolygonUpdates polygonUpdates) async {
    assert(polygonUpdates != null);
    await channel.invokeMethod<void>(
      'polygons#update',
      polygonUpdates._toMap(),
    );
  }

  /// Updates polyline configuration.
  ///
  /// Change listeners are notified once the update has been made on the
  /// platform side.
  ///
  /// The returned [Future] completes after listeners have been notified.
  Future<void> _updatePolylines(_PolylineUpdates polylineUpdates) async {
    assert(polylineUpdates != null);
    await channel.invokeMethod<void>(
      'polylines#update',
      polylineUpdates._toMap(),
    );
  }

  /// Updates circle configuration.
  ///
  /// Change listeners are notified once the update has been made on the
  /// platform side.
  ///
  /// The returned [Future] completes after listeners have been notified.
  Future<void> _updateCircles(_CircleUpdates circleUpdates) async {
    assert(circleUpdates != null);
    await channel.invokeMethod<void>(
      'circles#update',
      circleUpdates._toMap(),
    );
  }

  /// Starts an animated change of the map camera position.
  ///
  /// The returned [Future] completes after the change has been started on the
  /// platform side.
  Future<void> animateCamera(CameraUpdate cameraUpdate) async {
    await channel.invokeMethod<void>('camera#animate', <String, dynamic>{
      'cameraUpdate': cameraUpdate._toJson(),
    });
  }

  /// Changes the map camera position.
  ///
  /// The returned [Future] completes after the change has been made on the
  /// platform side.
  Future<void> moveCamera(CameraUpdate cameraUpdate) async {
    await channel.invokeMethod<void>('camera#move', <String, dynamic>{
      'cameraUpdate': cameraUpdate._toJson(),
    });
  }

  /// Sets the styling of the base map.
  ///
  /// Set to `null` to clear any previous custom styling.
  ///
  /// If problems were detected with the [mapStyle], including un-parsable
  /// styling JSON, unrecognized feature type, unrecognized element type, or
  /// invalid styler keys: [MapStyleException] is thrown and the current
  /// style is left unchanged.
  ///
  /// The style string can be generated using [map style tool](https://mapstyle.withgoogle.com/).
  /// Also, refer [iOS](https://developers.google.com/maps/documentation/ios-sdk/style-reference)
  /// and [Android](https://developers.google.com/maps/documentation/android-sdk/style-reference)
  /// style reference for more information regarding the supported styles.
  Future<void> setMapStyle(String mapStyle) async {
    final List<dynamic> successAndError =
        await channel.invokeMethod<List<dynamic>>('map#setStyle', mapStyle);
    final bool success = successAndError[0];
    if (!success) {
      throw MapStyleException(successAndError[1]);
    }
  }

  /// Return [LatLngBounds] defining the region that is visible in a map.
  Future<LatLngBounds> getVisibleRegion() async {
    final Map<String, dynamic> latLngBounds =
        await channel.invokeMapMethod<String, dynamic>('map#getVisibleRegion');
    final LatLng southwest = LatLng._fromJson(latLngBounds['southwest']);
    final LatLng northeast = LatLng._fromJson(latLngBounds['northeast']);

    return LatLngBounds(northeast: northeast, southwest: southwest);
  }

  /// Return [ScreenCoordinate] of the [LatLng] in the current map view.
  ///
  /// A projection is used to translate between on screen location and geographic coordinates.
  /// Screen location is in screen pixels (not display pixels) with respect to the top left corner
  /// of the map, not necessarily of the whole screen.
  Future<ScreenCoordinate> getScreenCoordinate(LatLng latLng) async {
    final Map<String, int> point = await channel.invokeMapMethod<String, int>(
        'map#getScreenCoordinate', latLng._toJson());
    return ScreenCoordinate(x: point['x'], y: point['y']);
  }

  /// Returns [LatLng] corresponding to the [ScreenCoordinate] in the current map view.
  ///
  /// Returned [LatLng] corresponds to a screen location. The screen location is specified in screen
  /// pixels (not display pixels) relative to the top left of the map, not top left of the whole screen.
  Future<LatLng> getLatLng(ScreenCoordinate screenCoordinate) async {
    final List<dynamic> latLng = await channel.invokeMethod<List<dynamic>>(
        'map#getLatLng', screenCoordinate._toJson());
    return LatLng(latLng[0], latLng[1]);
  }
}