main.dart

import 'dart:io';
import 'dart:math';

import 'package:flutter/material.dart';
import 'package:google_maps_webservice/places.dart';
import 'package:rxdart/rxdart.dart';

GoogleMapsPlaces _places =
    GoogleMapsPlaces(apiKey: "API_KEY");

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
//      home: CustomSearchScaffold(),
      home: new ExampleWidget(),
    );
  }


}

class ExampleWidget extends StatefulWidget {
  ExampleWidget({Key key}) : super(key: key);

  @override
  _ExampleWidgetState createState() => new _ExampleWidgetState();
}

/// State for [ExampleWidget] widgets.
class _ExampleWidgetState extends State<ExampleWidget> {
  final TextEditingController _controller = new TextEditingController();

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      body: new Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          new TextField(
            controller: _controller,
            decoration: new InputDecoration(
              hintText: 'Search places',
            ),
          ),
        ],
      ),
    );
  }
}



final homeScaffoldKey = GlobalKey<ScaffoldState>();
final searchScaffoldKey = GlobalKey<ScaffoldState>();

class CustomSearchScaffold extends PlacesAutocompleteWidget {
  CustomSearchScaffold()
      : super(
          apiKey: "API_KEY",
          sessionToken: Uuid().generateV4(),
          language: "en",
          components: [Component(Component.country, "in")],
        );

  @override
  _CustomSearchScaffoldState createState() => _CustomSearchScaffoldState();
}

class _CustomSearchScaffoldState extends PlacesAutocompleteState {
  @override
  Widget build(BuildContext context) {
    final appBar = AppBar(title: AppBarPlacesAutoCompleteTextField());
    final body = PlacesAutocompleteResult(
      onTap: (p) {
        displayPrediction(p, searchScaffoldKey.currentState);
        debugPrint("tapped");
      },
      logo: Row(
//        children: [FlutterLogo()],
        mainAxisAlignment: MainAxisAlignment.center,
      ),
    );
    return Scaffold(key: searchScaffoldKey, appBar: appBar, body: body);
  }

  @override
  void onResponseError(PlacesAutocompleteResponse response) {
    super.onResponseError(response);
    searchScaffoldKey.currentState.showSnackBar(
      SnackBar(content: Text(response.errorMessage)),
    );
  }

  @override
  void onResponse(PlacesAutocompleteResponse response) {
    super.onResponse(response);
    if (response != null && response.predictions.isNotEmpty) {
      searchScaffoldKey.currentState.showSnackBar(
        SnackBar(content: Text("Got answer")),
      );
    }
  }
}

class PlacesAutocompleteWidget extends StatefulWidget {
  final String apiKey;
  final String hint;
  final String language;
  final String sessionToken;
  final List<Component> components;
  final ValueChanged<PlacesAutocompleteResponse> onError;

  final String proxyBaseUrl;

  PlacesAutocompleteWidget({
    @required this.apiKey,
    this.hint = "Search",
    this.language,
    this.sessionToken,
    this.components,
    this.onError,
    Key key,
    this.proxyBaseUrl,
  }) : super(key: key);

  @override
  State<PlacesAutocompleteWidget> createState() {
    return _PlacesAutocompleteOverlayState();
  }

  static PlacesAutocompleteState of(BuildContext context) =>
      context.ancestorStateOfType(const TypeMatcher<PlacesAutocompleteState>());
}

abstract class PlacesAutocompleteState extends State<PlacesAutocompleteWidget> {
  TextEditingController _queryTextController;
  PlacesAutocompleteResponse _response;
  GoogleMapsPlaces _places;
  bool _searching;

  final _queryBehavior = BehaviorSubject<String>(seedValue: '');

  @override
  void initState() {
    super.initState();
    _queryTextController = TextEditingController(text: "");

    _places = GoogleMapsPlaces(
      apiKey: widget.apiKey,
      baseUrl: widget.proxyBaseUrl,
    );
    _searching = false;

    _queryTextController.addListener(_onQueryChange);

    _queryBehavior.stream
        .debounce(const Duration(milliseconds: 300))
        .listen(doSearch);
  }

  Future<Null> doSearch(String value) async {
    if (mounted && value.isNotEmpty) {
      setState(() {
        _searching = true;
      });

      final res = await _places.autocomplete(
        value,
        language: widget.language,
        sessionToken: widget.sessionToken,
        components: widget.components,
      );

      if (res.errorMessage?.isNotEmpty == true ||
          res.status == "REQUEST_DENIED") {
        onResponseError(res);
      } else {
        onResponse(res);
      }
    } else {
      onResponse(null);
    }
  }

  void _onQueryChange() {
    _queryBehavior.add(_queryTextController.text);
  }

  @override
  void dispose() {
    super.dispose();

    _places.dispose();
    _queryBehavior.close();
    _queryTextController.removeListener(_onQueryChange);
  }

  @mustCallSuper
  void onResponseError(PlacesAutocompleteResponse res) {
    if (!mounted) return;

    if (widget.onError != null) {
      widget.onError(res);
    }
    setState(() {
      _response = null;
      _searching = false;
    });
  }

  @mustCallSuper
  void onResponse(PlacesAutocompleteResponse res) {
    if (!mounted) return;

    setState(() {
      _response = res;
      _searching = false;
    });
  }
}

class _PlacesAutocompleteOverlayState extends PlacesAutocompleteState {
  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);

    final header = Column(children: <Widget>[
      Material(
          color: theme.dialogBackgroundColor,
          borderRadius: BorderRadius.only(
              topLeft: Radius.circular(2.0), topRight: Radius.circular(2.0)),
          child: Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: <Widget>[
              IconButton(
                color: theme.brightness == Brightness.light
                    ? Colors.black45
                    : null,
                icon: _iconBack,
                onPressed: () {
                  Navigator.pop(context);
                },
              ),
              Expanded(
                  child: Padding(
                child: _textField(context),
                padding: const EdgeInsets.only(right: 8.0),
              )),
            ],
          )),
      Divider(
          //height: 1.0,
          )
    ]);

    var body;
/*todo searching loader
//    if (_searching) {
//      body = Stack(
//        children: <Widget>[_Loader()],
//        alignment: FractionalOffset.bottomCenter,
//      );
//    } else*/
    if (_queryTextController.text.isEmpty ||
        _response == null ||
        _response.predictions.isEmpty) {
      body = Material(
        color: theme.dialogBackgroundColor,
//        child: widget.logo ?? PoweredByGoogleImage(),
        borderRadius: BorderRadius.only(
            bottomLeft: Radius.circular(2.0),
            bottomRight: Radius.circular(2.0)),
      );
    } else {
      body = SingleChildScrollView(
        child: Material(
          borderRadius: BorderRadius.only(
            bottomLeft: Radius.circular(2.0),
            bottomRight: Radius.circular(2.0),
          ),
          color: theme.dialogBackgroundColor,
          child: ListBody(
            children: _response.predictions
                .map(
                  (p) => PredictionTile(
                        prediction: p,
                        onTap: Navigator.of(context).pop,
                      ),
                )
                .toList(),
          ),
        ),
      );
    }

    final container = Container(
        margin: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 30.0),
        child: Stack(children: <Widget>[
          header,
          Padding(padding: EdgeInsets.only(top: 48.0), child: body),
        ]));

    if (Platform.isIOS) {
      return Padding(padding: EdgeInsets.only(top: 8.0), child: container);
    }
    return container;
  }

  Icon get _iconBack =>
      Platform.isIOS ? Icon(Icons.arrow_back_ios) : Icon(Icons.arrow_back);

  Widget _textField(BuildContext context) => TextField(
        controller: _queryTextController,
        autofocus: true,
        style: TextStyle(
            color: Theme.of(context).brightness == Brightness.light
                ? Colors.black87
                : null,
            fontSize: 16.0),
        decoration: InputDecoration(
          hintText: widget.hint,
          hintStyle: TextStyle(
            color: Theme.of(context).brightness == Brightness.light
                ? Colors.black45
                : null,
            fontSize: 16.0,
          ),
          border: InputBorder.none,
        ),
      );
}

class PredictionTile extends StatelessWidget {
  final Prediction prediction;
  final ValueChanged<Prediction> onTap;

  PredictionTile({@required this.prediction, this.onTap});

  @override
  Widget build(BuildContext context) {
    return ListTile(
      title: Text(prediction.description),
      onTap: () {
        if (onTap != null) {
          onTap(prediction);
        }
      },
    );
  }
}

class Uuid {
  final Random _random = Random();

  String generateV4() {
    // Generate xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx / 8-4-4-4-12.
    final int special = 8 + _random.nextInt(4);

    return '${_bitsDigits(16, 4)}${_bitsDigits(16, 4)}-'
        '${_bitsDigits(16, 4)}-'
        '4${_bitsDigits(12, 3)}-'
        '${_printDigits(special, 1)}${_bitsDigits(12, 3)}-'
        '${_bitsDigits(16, 4)}${_bitsDigits(16, 4)}${_bitsDigits(16, 4)}';
  }

  String _bitsDigits(int bitCount, int digitCount) =>
      _printDigits(_generateBits(bitCount), digitCount);

  int _generateBits(int bitCount) => _random.nextInt(1 << bitCount);

  String _printDigits(int value, int count) =>
      value.toRadixString(16).padLeft(count, '0');
}

class PlacesAutocompleteResult extends StatefulWidget {
  final ValueChanged<Prediction> onTap;
  final Widget logo;

  PlacesAutocompleteResult({this.onTap, this.logo});

  @override
  _PlacesAutocompleteResult createState() => _PlacesAutocompleteResult();
}

class _PlacesAutocompleteResult extends State<PlacesAutocompleteResult> {
  @override
  Widget build(BuildContext context) {
    final state = PlacesAutocompleteWidget.of(context);
    assert(state != null);

    if (state._queryTextController.text.isEmpty ||
        state._response == null ||
        state._response.predictions.isEmpty) {
      final children = <Widget>[];
      if (state._searching) {
//        children.add(_Loader());
      }
//      children.add(widget.logo ?? PoweredByGoogleImage());
      return Stack(children: children);
    }
    return PredictionsListView(
      predictions: state._response.predictions,
      onTap: widget.onTap,
    );
  }
}

class PredictionsListView extends StatelessWidget {
  final List<Prediction> predictions;
  final ValueChanged<Prediction> onTap;

  PredictionsListView({@required this.predictions, this.onTap});

  @override
  Widget build(BuildContext context) {
    return ListView(
      children: predictions
          .map((Prediction p) => PredictionTile(prediction: p, onTap: onTap))
          .toList(),
    );
  }
}

Future<Null> displayPrediction(Prediction p, ScaffoldState scaffold) async {
  if (p != null) {
    // get detail (lat/lng)
    PlacesDetailsResponse detail = await _places.getDetailsByPlaceId(p.placeId);
    final lat = detail.result.geometry.location.lat;
    final lng = detail.result.geometry.location.lng;

    scaffold.showSnackBar(
      SnackBar(content: Text("${p.description} - $lat/$lng")),
    );
  }
}

class _AppBarPlacesAutoCompleteTextFieldState
    extends State<AppBarPlacesAutoCompleteTextField> {
  @override
  Widget build(BuildContext context) {
    final state = PlacesAutocompleteWidget.of(context);
    assert(state != null);

    return Container(
        alignment: Alignment.topLeft,
        margin: EdgeInsets.only(top: 4.0),
        child: TextField(
          controller: state._queryTextController,
          autofocus: true,
          style: TextStyle(
            color: Theme.of(context).brightness == Brightness.light
                ? Colors.black.withOpacity(0.9)
                : Colors.white.withOpacity(0.9),
            fontSize: 16.0,
          ),
          decoration: InputDecoration(
            hintText: state.widget.hint,
            filled: true,
            fillColor: Theme.of(context).brightness == Brightness.light
                ? Colors.white30
                : Colors.black38,
            hintStyle: TextStyle(
              color: Theme.of(context).brightness == Brightness.light
                  ? Colors.black38
                  : Colors.white30,
              fontSize: 16.0,
            ),
            border: InputBorder.none,
          ),
        ));
  }
}

class AppBarPlacesAutoCompleteTextField extends StatefulWidget {
  @override
  _AppBarPlacesAutoCompleteTextFieldState createState() =>
      _AppBarPlacesAutoCompleteTextFieldState();
}