void main() {
  List<Map<String, dynamic>> incomeList = [];
  List<Map<String, dynamic>> expenseList = [];
  
  print('Welcome to the Budget Management Application!');

  while (true) {
    print('\nPlease choose an option:');
    print('1. Add income');
    print('2. Add expense');
    print('3. View summary');
    print('4. Exit');

    String? choice = stdin.readLineSync();

    switch (choice) {
      case '1':
        addIncome(incomeList);
        break;

      case '2':
        addExpense(expenseList);
        break;

      case '3':
        viewSummary(incomeList, expenseList);
        break;

      case '4':
        print('Exiting the application. Goodbye!');
        return;

      default:
        print('Invalid choice. Please try again.');
    }
  }
}

void addIncome(List<Map<String, dynamic>> incomeList) {
  print('Enter income description:');
  String? description = stdin.readLineSync();
  
  print('Enter income amount:');
  String? amountInput = stdin.readLineSync();
  double? amount = double.tryParse(amountInput!);

  if (description != null && description.isNotEmpty && amount != null && amount > 0) {
    incomeList.add({
      'description': description,
      'amount': amount
    });
    print('Income added!');
  } else {
    print('Invalid input. Please enter a valid description and positive amount.');
  }
}

void addExpense(List<Map<String, dynamic>> expenseList) {
  print('Enter expense description:');
  String? description = stdin.readLineSync();
  
  print('Enter expense amount:');
  String? amountInput = stdin.readLineSync();
  double? amount = double.tryParse(amountInput!);

  if (description != null && description.isNotEmpty && amount != null && amount > 0) {
    expenseList.add({
      'description': description,
      'amount': amount
    });
    print('Expense added!');
  } else {
    print('Invalid input. Please enter a valid description and positive amount.');
  }
}

void viewSummary(List<Map<String, dynamic>> incomeList, List<Map<String, dynamic>> expenseList) {
  double totalIncome = 0;
  double totalExpenses = 0;

  for (var income in incomeList) {
    totalIncome += income['amount'];
  }

  for (var expense in expenseList) {
    totalExpenses += expense['amount'];
  }

  double net = totalIncome - totalExpenses;
  
  print('\nSummary:');
  print('Total income: \$${totalIncome.toStringAsFixed(2)}');
  print('Total expenses: \$${totalExpenses.toStringAsFixed(2)}');
  
  if (net >= 0) {
    print('Net profit: \$${net.toStringAsFixed(2)}');
    double tax = net * 0.15;
    print('Tax to be paid: \$${tax.toStringAsFixed(2)}');
  } else {
    print('Net loss: \$${net.abs().toStringAsFixed(2)}');
  }
}