import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final weightController = TextEditingController();
  final startHController = TextEditingController();
  final endHController = TextEditingController();
  final startVController = TextEditingController();
  final endVController = TextEditingController();
  final oCJoule = TextEditingController();
  final oCWater = TextEditingController();
  final oCIron = TextEditingController();

  void _calculate() {
    double energy;
    double ekin = 0;
    double epot = 0;
    if (weightController.text.isEmpty) {
      return;
    }
    if (!startHController.text.isEmpty && !endHController.text.isEmpty) {
      epot = _calculatePot(double.parse(weightController.text), 
        double.parse(startHController.text), double.parse(endHController.text));
    } 
    if (!startVController.text.isEmpty && !endVController.text.isEmpty) {
      ekin = _calculateKin(double.parse(weightController.text), 
        double.parse(startVController.text), double.parse(endVController.text));
    }
    energy = ekin + epot;
    double water = energy / (80 * 4180); // 80 ist Differenz von 20 auf 100, 4180 sind Joule um 1l Wasser um 1 Grad zu erwärmen
    double iron = energy / (439 * 680); // 439 ist spezifische Wärmekapazität, 680 ist Differenz von 20 auf 700

    oCJoule.text = energy.toStringAsFixed(3) + " Joule Energie";
    oCWater.text = water.toStringAsFixed(3) + "l Wasser könnten damit zum Kochen gebracht werden";
    oCIron.text = iron.toStringAsFixed(3) + " kg Eisen können damit zum Glühen gebracht werden";
  }

  double _calculateKin(double weight, double startV, double endV) {
    return 0.5 * weight * (startV - endV).abs();
  }

  double _calculatePot(double weight, double startH, double endH) {
    double epot1 = weight * 9.81 * startH;
    double epot2 = weight * 9.81 * endH;
    return epot1 - epot2;
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Title(
                color: Colors.black,
                title: "Test",
                child: Container(
                  width: 1200,
                  height: 200.0,
                  decoration: BoxDecoration(
                    border: Border.all(
                      color: Colors.blue,
                    ),
                    borderRadius: BorderRadius.all(
                      Radius.circular(10.0),
                    ),
                  ),
                  child: Center(
                    child: Text(
                      'Start und Ende von Höhe und/oder Geschwindigkeit angeben',
                      style: TextStyle(fontSize: 28.0),
                    ),
                  ),
                )),
            TextField(
              decoration: InputDecoration(
                border: OutlineInputBorder(),
                labelText: "Gewicht",
                hintText: 'Gewicht in kg eingeben',
              ),
              keyboardType: TextInputType.number,
              controller: weightController,
            ),
            TextField(
              decoration: InputDecoration(
                border: OutlineInputBorder(),
                labelText: "Starthöhe",
                hintText: 'Starthöhe in m eingeben',
              ),
              keyboardType: TextInputType.number,
              controller: startHController,
            ),
            TextField(
              decoration: InputDecoration(
                border: OutlineInputBorder(),
                labelText: "Endhöhe",
                hintText: 'Endhöhe in m eingeben',
              ),
              keyboardType: TextInputType.number,
              controller: endHController,
            ),
            TextField(
              decoration: InputDecoration(
                border: OutlineInputBorder(),
                labelText: "Startgeschwindigkeit",
                hintText: 'Startgeschwindigkeit im m/s eingeben',
              ),
              keyboardType: TextInputType.number,
              controller: startVController,
            ),
            TextField(
              decoration: InputDecoration(
                border: OutlineInputBorder(),
                labelText: "Endgeschwindigkeit",
                hintText: 'Endgeschwindigkeit in m/s eingeben',
              ),
              keyboardType: TextInputType.number,
              controller: endVController,
            ),
            const SizedBox(height: 10),
            FloatingActionButton(
                onPressed: _calculate,
                tooltip: "Berechnen",
                child: const Icon(Icons.calculate)),
            TextField(
              showCursor: true,
              readOnly: true,
              controller: oCJoule,
              decoration: InputDecoration(
                labelText: "Gesamte Energie",
              ),
            ),
            TextField(
              showCursor: true,
              readOnly: true,
              controller: oCWater,
              decoration: InputDecoration(
                labelText: "Liter an Wasser zum Kochen",
              ),
            ),
            TextField(
              showCursor: true,
              readOnly: true,
              controller: oCIron,
              decoration: InputDecoration(
                labelText: "Kilogramm an Eisen zum Glühen",
              ),
            ),
          ],
        ),
      ),
    );
  }
}