import 'dart:io';

void main() {
  double totalIncome = 0;
  double totalExpenses = 0;

  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');

    stdout.write('\nEnter your choice: ');
    String? choice = stdin.readLineSync();

    switch (choice) {
      case '1':
        stdout.write('Enter income description: ');
        String? incomeDesc = stdin.readLineSync();

        stdout.write('Enter income amount: ');
        double? incomeAmount = double.tryParse(stdin.readLineSync() ?? '');

        if (incomeAmount != null && incomeAmount > 0) {
          totalIncome += incomeAmount;
          print('Income added!');
        } else {
          print('Invalid amount. Please try again.');
        }
        break;

      case '2':
        stdout.write('Enter expense description: ');
        String? expenseDesc = stdin.readLineSync();

        stdout.write('Enter expense amount: ');
        double? expenseAmount = double.tryParse(stdin.readLineSync() ?? '');

        if (expenseAmount != null && expenseAmount > 0) {
          totalExpenses += expenseAmount;
          print('Expense added!');
        } else {
          print('Invalid amount. Please try again.');
        }
        break;

      case '3':
        double netProfit = totalIncome - totalExpenses;
        double tax = 0;

        if (netProfit > 0) {
          tax = netProfit * 0.15; // 15% tax if profit
        }

        print('\nSummary:');
        print('Total income: \$${totalIncome.toStringAsFixed(2)}');
        print('Total expenses: \$${totalExpenses.toStringAsFixed(2)}');
        print('Net profit: \$${netProfit.toStringAsFixed(2)}');

        if (netProfit > 0) {
          print('Tax to be paid: \$${tax.toStringAsFixed(2)}');
        } else if (netProfit == 0) {
          print('No profit or loss.');
        } else {
          print('Loss: \$${(-netProfit).toStringAsFixed(2)}');
        }
        break;

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

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