mirrored_repositories/curso-flutter/conversor_moeda
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'dart:async';
import 'dart:convert';

const request = "https://api.hgbrasil.com/finance?format=json&key=b03af87a";

void main() async {
  runApp(MaterialApp(
      home: Home(),
      theme: ThemeData(
          hintColor: Colors.amber,
          primaryColor: Colors.white,
          inputDecorationTheme: InputDecorationTheme(
              enabledBorder: OutlineInputBorder(
                  borderSide: BorderSide(color: Colors.white)),
              focusedBorder: OutlineInputBorder(
                  borderSide: BorderSide(color: Colors.amber)),
              hintStyle: TextStyle(color: Colors.amber)))));
}

Future<Map> getData() async {
  http.Response response = await http.get(request);
  return json.decode(response.body);
}

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

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

class _HomeState extends State<Home> {
  final realController = TextEditingController();
  final dolarController = TextEditingController();
  final euroController = TextEditingController();

  double dolar;
  double euro;

  void _realChanged(String text) {
    if (text.isEmpty) {
      _clearAll();
      return;
    }
    double real = double.parse(text);
    dolarController.text = (real / dolar).toStringAsFixed(2);
    euroController.text = (real / euro).toStringAsFixed(2);
  }

  void _dolarChanged(String text) {
    if (text.isEmpty) {
      _clearAll();
      return;
    }
    double dolar = double.parse(text);
    realController.text = (dolar * this.dolar).toStringAsFixed(2);
    euroController.text = (dolar * this.dolar / euro).toStringAsFixed(2);
  }

  void _euroChanged(String text) {
    if (text.isEmpty) {
      _clearAll();
      return;
    }
    double euro = double.parse(text);
    realController.text = (euro * this.euro).toStringAsFixed(2);
    dolarController.text = (euro * this.euro / dolar).toStringAsFixed(2);
  }

  void _clearAll() {
    realController.text = "";
    dolarController.text = "";
    euroController.text = "";
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      appBar: AppBar(
        title: Text("\$Conversor\$"),
        backgroundColor: Colors.amber,
        centerTitle: true,
      ),
      body: FutureBuilder<Map>(
        future: getData(),
        builder: (context, snapshot) {
          switch (snapshot.connectionState) {
            case ConnectionState.none:
            case ConnectionState.waiting:
              return Center(
                  child: Text(
                "Carregando Dados...",
                style: TextStyle(color: Colors.amber, fontSize: 25.0),
                textAlign: TextAlign.center,
              ));
            default:
              if (snapshot.hasError) {
                return Center(
                    child: Text(
                  "Erro ao carregar dados :(",
                  style: TextStyle(color: Colors.amber, fontSize: 25.0),
                  textAlign: TextAlign.center,
                ));
              } else {
                dolar = snapshot.data['results']['currencies']['USD']['buy'];
                euro = snapshot.data['results']['currencies']['EUR']['buy'];

                return SingleChildScrollView(
                  padding: EdgeInsets.all(10),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: <Widget>[
                      Icon(
                        Icons.monetization_on,
                        size: 150,
                        color: Colors.amber,
                      ),
                      buildTextField(
                          "Reais", "R\$", realController, _realChanged),
                      Divider(),
                      buildTextField(
                          "Dolares", "U\$", dolarController, _dolarChanged),
                      Divider(),
                      buildTextField("Euros", "€", euroController, _euroChanged)
                    ],
                  ),
                );
              }
          }
        },
      ),
    );
  }
}

Widget buildTextField(
    String label, String prefix, TextEditingController c, Function f) {
  return TextField(
    controller: c,
    decoration: InputDecoration(
        labelText: label,
        labelStyle: TextStyle(color: Colors.amber),
        border: OutlineInputBorder(),
        prefixText: prefix),
    style: TextStyle(color: Colors.amber, fontSize: 25),
    onChanged: f,
    keyboardType: TextInputType.numberWithOptions(decimal: true),
  );
}
