Basic-Habit-Tracking-App/my_app/lib/main.dart

import 'dart:convert';

import 'dart:io';

import 'dart:math';

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import 'package:big_fraction/big_fraction.dart';

import 'package:flutter_heatmap_calendar/flutter_heatmap_calendar.dart';

import 'package:path_provider/path_provider.dart';

class ReadWrite {
  static Future<File> get_history_file() async {
    Directory? directory = await getApplicationDocumentsDirectory();

    return File("${directory.path}/history.json");
  }

  static Future<File> get_first_time_file() async {
    Directory? directory = await getApplicationDocumentsDirectory();

    return File("${directory.path}/first-time.json");
  }

  static Future<List<DateTime>> read_history() async {
    final file = await get_history_file();

    List<List<int>> tuple_history = [];

    try {
      var text = await file.readAsString();

      List<dynamic> temp = jsonDecode(text);

      for (dynamic e in temp) {
        List<dynamic> l = e;

        int a = l[0];
        int b = l[1];
        int c = l[2];

        tuple_history.add([a, b, c]);
      }

      print('history found, and it has ${tuple_history.length} elements');
    } on PathNotFoundException {
      print('no history found');
    }

    var history = <DateTime>[];

    for (var e in tuple_history) {
      history.add(DateTime(e[0], e[1], e[2]));
    }

    return history;
  }

  static Future<Null> writeTextFile(List<DateTime> history) async {
    final file = await get_history_file();

    var tuple_history = <List<int>>[];

    for (DateTime dt in history) {
      tuple_history.add([dt.year, dt.month, dt.day]);
    }

    file.writeAsString(jsonEncode(tuple_history));

    return null;
  }

  static Future<DateTime> get_first_time() async {
    final file = await get_first_time_file();

    DateTime first_time;

    try {
      var text = await file.readAsString();

      List<dynamic> readable = jsonDecode(text);

      int year = readable[0];
      int month = readable[1];
      int day = readable[2];

      first_time = DateTime(year, month, day);

      print('first time day found');
    } on PathNotFoundException {
      print('no first time day found, assuming today');

      DateTime now = DateTime.now();

      List<int> writeable = <int>[now.year, now.month, now.day];

      file.writeAsString(jsonEncode(writeable));

      first_time = DateTime(now.year, now.month, now.day);
    }

    return first_time;
  }
}

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

class MyAppState extends ChangeNotifier {
  var history = <DateTime>[];

  DateTime first_time = DateTime(1999, 1, 1);

  var percentage = 0.0;

  MyAppState() {
    ReadWrite.read_history().then((x) {
      history = x;

      recalculate_percentage();

      notifyListeners();
    });

    ReadWrite.get_first_time().then((x) {
      first_time = x;

      recalculate_percentage();

      notifyListeners();
    });
  }

  void recalculate_percentage() {
    var now = DateTime.now();

    now = DateTime(now.year, now.month, now.day);

    var cutoff = DateTime(now.year, now.month, now.day - 120);

    while (history.length > 0 && history[0].isBefore(cutoff)) {
      history.removeAt(0);
    }

    if (history.length == 0) {
      percentage = 0.0;
    } else if (first_time.isAfter(cutoff)) {
      // print("line 177: ${history.length} / ${now.difference(first_time).inDays}");

      percentage = history.length / (now.difference(first_time).inDays + 1);
    } else {
      percentage = history.length / 120;
    }

    // print("percentage = ${percentage}");
  }

  void incrementCounter() async {
    var now = DateTime.now();

    now = DateTime(now.year, now.month, now.day);

    if (history.length == 0 || history[history.length - 1] != now) {
      history.add(now);

      await ReadWrite.writeTextFile(history);
    }

    recalculate_percentage();

    notifyListeners();
  }

  void decrementCounter() async {
    var now = DateTime.now();

    now = DateTime(now.year, now.month, now.day);

    if (history.length > 0 && history[history.length - 1] == now) {
      history.remove(now);

      await ReadWrite.writeTextFile(history);
    }

    recalculate_percentage();

    notifyListeners();
  }

  void clear_counter() {
    history.clear();

    recalculate_percentage();

    notifyListeners();
  }
}

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

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
        create: (context) => new MyAppState(),
        child: MaterialApp(
          title: 'Flutter Demo',
          theme: ThemeData(
            colorScheme: ColorScheme.fromSeed(seedColor: Colors.red),
            useMaterial3: true,
          ),
          home: const MyHomePage(title: 'Habit Tracker (v0.01)'),
        ));
  }
}

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

  final String title;

  @override
  Widget build(BuildContext context) {
    var appState = context.watch<MyAppState>();

    final theme = Theme.of(context);

    var percentage = appState.percentage;

    var size = 200.0;

    var now = DateTime.now();

    var cutoff = DateTime(now.year, now.month, now.day - 120);

    DateTime startDate;

    if (appState.first_time.isAfter(cutoff)) {
      startDate = appState.first_time;
    } else {
      startDate = cutoff;
    }

    var inverse_primary = theme.colorScheme.inversePrimary;

    var secondary = theme.colorScheme.secondary;

    var primary = theme.colorScheme.primary;

    return Scaffold(
      appBar: AppBar(
        backgroundColor: inverse_primary,
        title: Text(title),
      ),
      body: Center(
        child: ListView(
          children: [
            Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                HeatMap(
                  defaultColor: inverse_primary,
                  colorMode: ColorMode.opacity,
                  startDate: startDate,
                  endDate: now,
                  showText: false,
                  scrollable: false,
                  showColorTip: false,
                  datasets: {
                    for (int i = 0; i < 120; i++)
                      DateTime(now.year, now.month, now.day - i): 1,
                    for (DateTime dt in appState.history) dt: 2,
                  },
                  colorsets: {
                    1: primary,
                  },
                ),

                SizedBox(height: 10),

                Stack(
                  alignment: AlignmentDirectional.center,
                  children: <Widget>[
                    Center(
                      child: SizedBox(
                        width: size,
                        height: size,
                        child: CircularProgressIndicator(
                          color: Theme.of(context).colorScheme.primary,
                          strokeWidth: 8,
                          value: percentage,
                        ),
                      ),
                    ),
                    Center(
                      child: Text(
                        '${(percentage * 100).toStringAsFixed(2)}%',
                        style: theme.textTheme.displayMedium!,
                      ),
                    ),
                  ],
                ),

                SizedBox(height: 10),

                Row(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    ElevatedButton.icon(
                      onPressed: () async {
                        appState.decrementCounter();
                      },
                      icon: Icon(Icons.remove),
                      label: Text('Failure'),
                    ),
                    SizedBox(width: 10),
                    ElevatedButton.icon(
                      onPressed: () async {
                        appState.incrementCounter();
                      },
                      icon: Icon(Icons.add),
                      label: Text('Success'),
                    ),
                  ],
                ),

                // SizedBox(height: 10),

                // Text("(The denominator is ${now.difference(appState.first_time).inDays})"),
              ],
            ),
          ],
        ),
      ),
    );
  }
}