import 'dart:io';

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

  while (true) {
    print("\nBudget 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();

    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 (desc != null && amount != null && amount > 0) {
          incomeList.add({desc: amount});
          print("Income added successfully.");
        } else {
          print("Invalid input. Please enter a valid amount.");
        }
        break;

      case '2':
        stdout.write("Enter expense description: ");
        String? desc = stdin.readLineSync();
        stdout.write("Enter expense amount: ");
        double? amount = double.tryParse(stdin.readLineSync() ?? '');
        if (desc != null && amount != null && amount > 0) {
          expenseList.add({desc: amount});
          print("Expense added successfully.");
        } else {
          print("Invalid input. Please enter a valid amount.");
        }
        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 netProfit = totalIncome - totalExpense;

        print("\n--- Budget Summary ---");
        print("Total Income: \$${totalIncome.toStringAsFixed(2)}");
        print("Total Expenses: \$${totalExpense.toStringAsFixed(2)}");
        print("Net Profit/Loss: \$${netProfit.toStringAsFixed(2)}");

        if (netProfit > 0) {
          double tax = netProfit * 0.15;
          print("Tax to Pay (15%): \$${tax.toStringAsFixed(2)}");
        }
        print("----------------------");
        break;

      case '4':
        print("Exiting Budget Management...");
        return;

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