main.dart

/*
 *  https://dartpad.dev/e15c0e0bc625f59e8c747ea9c1d82a8b
 */

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

final ValueNotifier<bool> useFix = ValueNotifier<bool>(false);
const int payloadLength = 70000;

void main() => runApp(App());

class App extends StatelessWidget {
  Widget build(BuildContext context) => MaterialApp(
        home: Scaffold(
          body: SafeArea(
            child: Center(
              child: SingleChildScrollView(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  crossAxisAlignment: CrossAxisAlignment.center,
                  children: <Widget>[
                    Row(
                      mainAxisAlignment: MainAxisAlignment.center,
                      crossAxisAlignment: CrossAxisAlignment.center,
                      children: [
                        Text('Use fix:', textScaleFactor: 1.5),
                        ValueListenableBuilder<bool>(
                          valueListenable: useFix,
                          builder: (context, currentValue, _) => Switch(
                            value: currentValue,
                            onChanged: (newValue) => useFix.value = newValue,
                          ),
                        ),
                      ],
                    ),
                    SizedBox(height: 50),
                    SizedBox(
                      child: CircularProgressIndicator(),
                      height: 75,
                      width: 75,
                    ),
                    SizedBox(height: 50),
                    Text('Payload length: $payloadLength',
                        textScaleFactor: 1.25),
                    SizedBox(height: 15),
                    OutlinedButton(
                      child: Text('IMPACT ON EVENT LOOP'),
                      onPressed: () async => impactOnEventLoop(),
                    ),
                  ],
                ),
              ),
            ),
          ),
        ),
      );
}

Future<void> impactOnEventLoop() async {
  /// Если useFix.value == true, нужно добавить фикс, который позволит прогрессу крутитmся без зависания, а 
  /// коду искать простые числа.

  
  final primeList = <int>[];
  final sourceData = generateSourceData(payloadLength);
  for (final i in sourceData) {
    if (!i.isPrime) continue;
    primeList.add(i);
  }
  print('Number of primes: ${primeList.length}');
}

Iterable<int> generateSourceData(int length) sync* {
  for (var i = 0; i < length; i++) {
    yield i;
  }
}

extension IsPrimeX on int {
  bool get isPrime {
    if (this > 1) {
      for (int i = 2; i < this; i++) if (this % i == 0) return false;
      return true;
    } else {
      return false;
    }
  }
}