import 'package:fl_chart/fl_chart.dart';
import 'package:flutter/material.dart';
import 'dart:math';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

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

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
      ),
      body: Padding(
        padding: const EdgeInsets.all(20),
        child: RotatedBox(
          quarterTurns: 1,
          child: MyBarChart(),
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }
}

class MyBarChart extends StatelessWidget {
  final List<ChartData> data = ChartData.exampleData();

  double get maxY => max(
        data.map((d) => d.gpa).reduce((a, b) => max(a, b)),
        data.map((d) => d.year).reduce((a, b) => max(a, b)),
      ).toDouble();

  List<BarChartGroupData> _chartGroupData() {
    return data
        .map((d) => BarChartGroupData(
              x: data.indexOf(d),
              barRods: [
                BarChartRodData(toY: d.year.toDouble()),
                BarChartRodData(toY: d.gpa.toDouble())
              ],
            ))
        .toList();
  }

  BarChartData _chartData() {
    return BarChartData(
      barGroups: _chartGroupData(),
      maxY: maxY + 0.5,
      titlesData: FlTitlesData(
        show: true,
        topTitles: AxisTitles(sideTitles: SideTitles(showTitles: false)),
        leftTitles: AxisTitles(sideTitles: SideTitles(showTitles: false)),
        rightTitles: AxisTitles(
            sideTitles: SideTitles(
                reservedSize: 40,
                showTitles: true,
                getTitlesWidget: (y, meta) => SideTitleWidget(
                    angle: -1.57079633,
                    child: Text(meta.formattedValue),
                    axisSide: meta.axisSide))),
        bottomTitles: AxisTitles(
            sideTitles: SideTitles(
                reservedSize: 50,
                showTitles: true,
                getTitlesWidget: (x, meta) => SideTitleWidget(
                    angle: -1.57079633,
                    child: Text(data[x.floor()].name),
                    axisSide: meta.axisSide))),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return BarChart(_chartData());
  }
}

class ChartData {
  ChartData({required this.name, required this.gpa, required this.year});

  String name;
  int gpa;
  int year;

  static List<ChartData> exampleData() {
    return [
      ChartData(name: "John", gpa: 2, year: 1),
      ChartData(name: "Jane", gpa: 3, year: 2),
      ChartData(name: "Doe", gpa: 4, year: 3),
    ];
  }
}