import 'dart:io';

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

  const double taxRate = 0.15;
  bool isRunning = true;

  print('Welcome to the Budget Management Application!');

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

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

    if (choice == '1') {
      stdout.write('Enter income description: ');
      String description = stdin.readLineSync() ?? 'Unknown Income';

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

      if (amount != null && amount >= 0) {
        incomeList.add({'description': description, 'amount': amount});
        print('Income added!');
      } else {
        print('Invalid amount. Income must be a non-negative number.');
      }
    } else if (choice == '2') {
      stdout.write('Enter expense description: ');
      String description = stdin.readLineSync() ?? 'Unknown Expense';

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

      if (amount != null && amount >= 0) {
        expenseList.add({'description': description, 'amount': amount});
        print('Expense added!');
      } else {
        print('Invalid amount. Expense must be a non-negative number.');
      }
    } else if (choice == '3') {
      double totalIncome = 0;
      double totalExpenses = 0;

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

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

      double netAmount = totalIncome - totalExpenses;
      double tax = netAmount > 0 ? netAmount * taxRate : 0;

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

      if (netAmount > 0) {
        print('Your net profit is \$${netAmount.toStringAsFixed(2)}');
        print('Tax to be paid: \$${tax.toStringAsFixed(2)}');
      } else if (netAmount < 0) {
        print('Your net loss is \$${netAmount.abs().toStringAsFixed(2)}');
      } else {
        print('You broke even. No profit and no loss.');
      }
    } else if (choice == '4') {
      print('Exiting the application. Goodbye!');
      isRunning = false;
    } else {
      print('Invalid choice. Please select a number from 1 to 4.');
    }
  }
}