import 'dart:io';

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

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

    if (choice == '4') {
      print("Exiting the application. 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 ?? 'Income': amount});
          print("Income added!");
        } else {
          print("Invalid amount. Please enter a positive number.");
        }
        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 ?? 'Expense': amount});
          print("Expense added!");
        } else {
          print("Invalid amount. Please enter a positive number.");
        }
        break;

      case '3':
        double totalIncome = incomeList.fold(0, (sum, item) => sum + item.values.first);
        double totalExpenses = expenseList.fold(0, (sum, item) => sum + item.values.first);
        double net = totalIncome - totalExpenses;
        double tax = net > 0 ? net * 0.15 : 0;

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

        if (net >= 0) {
          print("Net profit: \$${net.toStringAsFixed(2)}");
          print("Tax to be paid: \$${tax.toStringAsFixed(2)}");
        } else {
          print("Net loss: \$${net.abs().toStringAsFixed(2)}");
        }
        break;

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