wetterApp/lib/components/locations/add_location_by_search_form.dart

import 'package:flutter/material.dart';
import 'package:wetter/models/location_model.dart';
import 'package:wetter/services/openstreetmap_api_service.dart';
import 'package:wetter/services/utils.dart';

class AddLocationBySearchForm extends StatefulWidget {
  final Function saveNewLocation;

  const AddLocationBySearchForm({Key? key, required this.saveNewLocation})
      : super(key: key);

  @override
  State<AddLocationBySearchForm> createState() =>
      _AddLocationBySearchFormState();
}

class _AddLocationBySearchFormState extends State<AddLocationBySearchForm> {
  final _formKey = GlobalKey<FormState>();
  final searchLocationFormController = TextEditingController();
  final _debouncer = Debouncer(milliseconds: 500);
  bool _showResults = false;
  bool _locationSearchHasFocus = false;
  List<LocationModel>? _locations;

  @override
  Widget build(BuildContext context) {
    return Form(
        key: _formKey,
        child: Column(
          children: [
            FocusScope(
                child: Focus(
                    onFocusChange: (focus) {
                      setState(() {
                        _locationSearchHasFocus = !_locationSearchHasFocus;
                      });
                    },
                    child: TextFormField(
                      onChanged: (value) {
                        _debouncer.run(() {
                          OpenStreetMapAPI.getLocationsFromSearch(value)
                              .then((l) {
                            setState(() {
                              _locations = l;
                              _showResults = true;
                            });
                          });
                        });
                      },
                      decoration: const InputDecoration(
                          border: UnderlineInputBorder(),
                          labelText: "Location Name"),
                    ))),
            if (_showResults && _locationSearchHasFocus) _showResultList(),
          ],
        ));
  }

  Column _showResultList() {
    if (_locations == null) {
      return Column(
        children: const [],
      );
    }
    if (_locations!.isEmpty) {
      return Column(
        children: [_singleResult(name: "No result")],
      );
    }
    Iterable<LocationModel> locationsToShow = _locations!;
    if (locationsToShow.length > 3) {
      locationsToShow = _locations!.getRange(0, 3);
    }
    return Column(children: [
      for (LocationModel location in locationsToShow)
        _singleResult(name: location.name, location: location)
    ]);
  }

  Widget _singleResult({required String name, LocationModel? location}) {
    return GestureDetector(
        onTap: () {
          if (location != null) {
            widget.saveNewLocation(
                location.name, location.latitude, location.longitude);
          }
        },
        child: Card(
            child: Padding(
                padding: const EdgeInsets.all(5),
                child: Row(children: [
                  Flexible(
                      child: Text(name,
                          style: Theme.of(context).textTheme.titleMedium))
                ]))));
  }
}