import 'dart:io';

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

  while (true) {
    print("\nBudget Manager");
    print("1. Add Income");
    print("2. Add Expense");
    print("3. Show Summary");
    print("4. Exit");

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

    if (choice == '1') {
      stdout.write("Enter income amount: ");
      double? amount = double.tryParse(stdin.readLineSync()!);
      if (amount != null && amount > 0) {
        totalIncome += amount;
        print("Income added.");
      } else {
        print("Invalid amount.");
      }
    } else if (choice == '2') {
      stdout.write("Enter expense amount: ");
      double? amount = double.tryParse(stdin.readLineSync()!);
      if (amount != null && amount > 0) {
        totalExpenses += amount;
        print("Expense added.");
      } else {
        print("Invalid amount.");
      }
    } else if (choice == '3') {
      double netBalance = totalIncome - totalExpenses;
      print("\nSummary:");
      print("Total Income: \$${totalIncome.toStringAsFixed(2)}");
      print("Total Expenses: \$${totalExpenses.toStringAsFixed(2)}");
      print("Net Balance: \$${netBalance.toStringAsFixed(2)}");
    } else if (choice == '4') {
      print("Goodbye!");
      break;
    } else {
      print("Invalid choice, try again.");
    }
  }
}