import 'dart:io';

void main() {
  List<Map<String, double>> incomeList = [];
  List<Map<String, double>> expenseList = [];

  while (true) {
    print('\n--- Budget Management ---');
    print('1. Add Income');
    print('2. Add Expense');
    print('3. View Summary');
    print('4. Exit');
    stdout.write('Choose an option: ');
    String? choice = stdin.readLineSync();

    if (choice == '4') {
      print('Exiting Budget Manager... Goodbye!');
      break;
    }

    switch (choice) {
      case '1':
        stdout.write('Enter income description: ');
        String? desc = stdin.readLineSync();
        stdout.write('Enter income amount: ');
        double? amount = double.tryParse(stdin.readLineSync()!);

        if (amount != null && amount > 0) {
          incomeList.add({desc ?? "Unnamed": amount});
          print('Income added successfully.');
        } else {
          print('Invalid amount! Must be positive.');
        }
        break;

      case '2':
        stdout.write('Enter expense description: ');
        String? desc = stdin.readLineSync();
        stdout.write('Enter expense amount: ');
        double? amount = double.tryParse(stdin.readLineSync()!);

        if (amount != null && amount > 0) {
          expenseList.add({desc ?? "Unnamed": amount});
          print('Expense added successfully.');
        } else {
          print('Invalid amount! Must be positive.');
        }
        break;

      case '3':
        double totalIncome = incomeList.fold(0, (sum, item) => sum + item.values.first);
        double totalExpense = expenseList.fold(0, (sum, item) => sum + item.values.first);
        double net = totalIncome - totalExpense;

        print('\n--- Summary ---');
        print('Total Income: \$${totalIncome.toStringAsFixed(2)}');
        print('Total Expenses: \$${totalExpense.toStringAsFixed(2)}');

        String result = net >= 0
            ? 'Your net profit is \$${net.toStringAsFixed(2)}'
            : 'Your net loss is \$${(-net).toStringAsFixed(2)}';
        print(result);

        if (net > 0) {
          double tax = net * 0.15;
          print('Tax to pay: \$${tax.toStringAsFixed(2)}');
        }
        break;

      default:
        print('Invalid choice! Try again.');
    }
  }
}