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> {
  @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(),
        ),
      ),
    );
  }
}

class MyBarChart extends StatelessWidget {
  MyBarChart({super.key});

  final List<ChartData> data = ChartData.exampleData();
  final double _chartTextRotation = -1.57079633;

  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();

  SideTitleWidget _getBottomSideTitleWidget(double y, TitleMeta meta) {
    return SideTitleWidget(
      angle: _chartTextRotation,
      axisSide: meta.axisSide,
      child: Center(child: Text(meta.formattedValue)),
    );
  }

  SideTitleWidget _getLeftSideTitleWidget(double x, TitleMeta meta) {
    return SideTitleWidget(
      angle: _chartTextRotation,
      axisSide: meta.axisSide,
      child: Align(
        alignment: Alignment.centerRight,
        child: Text(data[x.floor()].name),
      ),
    );
  }

  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: const AxisTitles(sideTitles: SideTitles(showTitles: false)),
        leftTitles: const AxisTitles(sideTitles: SideTitles(showTitles: false)),
        rightTitles: AxisTitles(
            sideTitles: SideTitles(
                reservedSize: 40,
                showTitles: true,
                getTitlesWidget: _getBottomSideTitleWidget)),
        bottomTitles: AxisTitles(
            sideTitles: SideTitles(
                reservedSize: 50,
                showTitles: true,
                getTitlesWidget: _getLeftSideTitleWidget)),
      ),
    );
  }

  @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),
    ];
  }
}