kz_educa/lib/screens/savings_calculator_screen.dart

// lib/screens/savings_calculator_screen.dart
import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:shared_preferences/shared_preferences.dart'; // Importar shared_preferences

class SavingsCalculatorScreen extends StatefulWidget {
  const SavingsCalculatorScreen({super.key});

  @override
  State<SavingsCalculatorScreen> createState() => _SavingsCalculatorScreenState();
}

class _SavingsCalculatorScreenState extends State<SavingsCalculatorScreen> {
  final TextEditingController _initialDepositController = TextEditingController();
  final TextEditingController _interestRateController = TextEditingController();
  int _savingPeriodMonths = 6;
  DateTime _startDate = DateTime.now();
  double _calculatedFinalAmount = 0.0;
  double _calculatedInterest = 0.0;
  String _currentCurrency = 'KZ'; // Adicionar a variável para a moeda

  @override
  void initState() {
    super.initState();
    _loadCurrency(); // Chamar a função para carregar a moeda no initState
  }

  // Função para carregar a moeda das Shared Preferences
  Future<void> _loadCurrency() async {
    final prefs = await SharedPreferences.getInstance();
    setState(() {
      _currentCurrency = prefs.getString('currencySymbol') ?? 'KZ'; // Pega o símbolo salvo
    });
  }

  Future<void> _selectDate(BuildContext context) async {
    final DateTime? picked = await showDatePicker(
      context: context,
      initialDate: _startDate,
      firstDate: DateTime(2000),
      lastDate: DateTime(2101),
      locale: const Locale('pt', 'BR'),
    );
    if (picked != null && picked != _startDate) {
      setState(() {
        _startDate = picked;
      });
    }
  }

  void _calculateSavings() {
    final double initialDeposit = double.tryParse(_initialDepositController.text) ?? 0.0;
    final double annualInterestRate = double.tryParse(_interestRateController.text) ?? 0.0;

    if (initialDeposit <= 0 || annualInterestRate <= 0) {
      setState(() {
        _calculatedFinalAmount = 0.0;
        _calculatedInterest = 0.0;
      });
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Por favor, insira valores válidos para depósito e taxa de juros.')),
      );
      return;
    }

    // Convertendo a taxa anual para mensal e para decimal
    final double monthlyInterestRate = (annualInterestRate / 100) / 12;
    // Calculando juros compostos mensais
    double finalAmount = initialDeposit * (1 + monthlyInterestRate);
    for (int i = 1; i < _savingPeriodMonths; i++) {
      finalAmount = finalAmount * (1 + monthlyInterestRate);
    }

    double totalInterest = finalAmount - initialDeposit;

    setState(() {
      _calculatedFinalAmount = finalAmount;
      _calculatedInterest = totalInterest;
    });
  }

  void _resetFields() {
    setState(() {
      _initialDepositController.clear();
      _interestRateController.clear();
      _savingPeriodMonths = 6;
      _startDate = DateTime.now();
      _calculatedFinalAmount = 0.0;
      _calculatedInterest = 0.0;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Calculadora de Economia'),
        actions: [
          IconButton(
            icon: const Icon(Icons.history),
            onPressed: () {
              ScaffoldMessenger.of(context).showSnackBar(
                const SnackBar(content: Text('Histórico de cálculos (a ser implementado)')),
              );
            },
          ),
        ],
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            TextFormField(
              controller: _initialDepositController,
              keyboardType: TextInputType.number,
              decoration: InputDecoration( // Use InputDecoration para o suffixText dinâmico
                labelText: 'Depósito inicial',
                border: const OutlineInputBorder(),
                suffixText: _currentCurrency, // Usar a moeda carregada
              ),
            ),
            const SizedBox(height: 20),
            TextFormField(
              controller: _interestRateController,
              keyboardType: TextInputType.number,
              decoration: const InputDecoration(
                labelText: 'Taxa de juros',
                border: OutlineInputBorder(),
                suffixText: '%/ano',
              ),
            ),
            const SizedBox(height: 20),
            Row(
              children: [
                const Text('Período de poupança:', style: TextStyle(fontSize: 16)),
                const SizedBox(width: 10),
                DropdownButton<int>(
                  value: _savingPeriodMonths,
                  onChanged: (int? newValue) {
                    setState(() {
                      _savingPeriodMonths = newValue!;
                    });
                  },
                  items: <int>[3, 6, 12, 24, 36, 60] // Exemplo de períodos
                      .map<DropdownMenuItem<int>>((int value) {
                    return DropdownMenuItem<int>(
                      value: value,
                      child: Text('$value Meses'),
                    );
                  }).toList(),
                ),
              ],
            ),
            const SizedBox(height: 20),
            Row(
              children: [
                Text(
                  'Data de Início',
                  style: TextStyle(fontSize: 16, color: Colors.grey[700]),
                ),
                const SizedBox(width: 10),
                Expanded(
                  child: GestureDetector(
                    onTap: () => _selectDate(context),
                    child: AbsorbPointer(
                      child: TextFormField(
                        decoration: InputDecoration(
                          hintText: DateFormat('dd \'de\' MMM \'de\' yyyy', 'pt_BR').format(_startDate),
                          suffixIcon: const Icon(Icons.calendar_today),
                          border: const OutlineInputBorder(),
                        ),
                      ),
                    ),
                  ),
                ),
              ],
            ),
            const SizedBox(height: 30),
            SizedBox(
              width: double.infinity,
              child: ElevatedButton(
                onPressed: _calculateSavings,
                style: ElevatedButton.styleFrom(
                  backgroundColor: Colors.blue,
                  foregroundColor: Colors.white,
                  padding: const EdgeInsets.symmetric(vertical: 15),
                  shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(8.0),
                  ),
                ),
                child: const Text('Calcular', style: TextStyle(fontSize: 18)),
              ),
            ),
            const SizedBox(height: 10),
            SizedBox(
              width: double.infinity,
              child: TextButton(
                onPressed: _resetFields,
                child: const Text('Redefinir campos', style: TextStyle(color: Colors.blue)),
              ),
            ),
            const SizedBox(height: 30),
            if (_calculatedFinalAmount > 0)
              Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  const Text('Resultado:', style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold)),
                  const SizedBox(height: 10),
                  Text(
                    // Usar _currentCurrency aqui para exibir o símbolo correto
                    'Valor Final: $_currentCurrency ${NumberFormat.currency(locale: 'pt_BR', symbol: '').format(_calculatedFinalAmount)}',
                    style: const TextStyle(fontSize: 18),
                  ),
                  Text(
                    // Usar _currentCurrency aqui para exibir o símbolo correto
                    'Juros Ganhos: $_currentCurrency ${NumberFormat.currency(locale: 'pt_BR', symbol: '').format(_calculatedInterest)}',
                    style: const TextStyle(fontSize: 18, color: Colors.green),
                  ),
                ],
              ),
          ],
        ),
      ),
    );
  }
}