import 'dart:math';

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Несие калькуляторы',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: CalculatorPage(),
    );
  }
}

class CalculatorPage extends StatefulWidget {
  @override
  _CalculatorPageState createState() => _CalculatorPageState();
}

class _CalculatorPageState extends State<CalculatorPage> {
  double loanAmount = 0;
  double interestRate = 0;
  int loanTerm = 0;
  double monthlyPayment = 0;

  void calculateMonthlyPayment() async {
    if (loanAmount > 0 && interestRate > 0 && loanTerm > 0) {
      double monthlyInterestRate = interestRate / 100 / 12;
      double totalPayments = loanTerm * 12;

      double discountFactor = await Future(() {
        return (pow(1 + monthlyInterestRate, totalPayments) - 1) /
            (monthlyInterestRate * pow(1 + monthlyInterestRate, totalPayments));
      });

      setState(() {
        monthlyPayment = loanAmount / discountFactor;
      });
    } else {
      setState(() {
        monthlyPayment = 0;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Несие калькуляторы'),
      ),
      body: SingleChildScrollView(
        child: Padding(
          padding: EdgeInsets.all(16.0),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              const Text(
                'Несие сомасы',
                style: TextStyle(fontSize: 20),
              ),
              SizedBox(height: 8),
              TextFormField(
                keyboardType: TextInputType.number,
                onChanged: (value) {
                  setState(() {
                    loanAmount = double.tryParse(value) ?? 0;
                  });
                },
              ),
              SizedBox(height: 16),
              const Text(
                'Пайыздық мөлшерлеме (%)',
                style: TextStyle(fontSize: 20),
              ),
              SizedBox(height: 8),
              TextFormField(
                keyboardType: TextInputType.number,
                onChanged: (value) {
                  setState(() {
                    interestRate = double.tryParse(value) ?? 0;
                  });
                },
              ),
              SizedBox(height: 16),
              const Text(
                'Несие мерзімі (жылдар)',
                style: TextStyle(fontSize: 20),
              ),
              const SizedBox(height: 8),
              TextFormField(
                keyboardType: TextInputType.number,
                onChanged: (value) {
                  setState(() {
                    loanTerm = int.tryParse(value) ?? 0;
                  });
                },
              ),
              const SizedBox(height: 16),
              ElevatedButton(
                onPressed: () {
                  calculateMonthlyPayment();
                },
                child: Text('Есептеу'),
              ),
              const SizedBox(height: 16),
              const Text(
                'Ай сайынғы төлем:',
                style: TextStyle(fontSize: 24),
              ),
              const SizedBox(height: 8),
              Text(
                '$monthlyPayment \теңге',
                style: const TextStyle(fontSize: 32, fontWeight: FontWeight.bold),
              ),
            ],
          ),
        ),
      ),
    );
  }
}