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 == '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: amount});
        print("Income added!");
      } else {
        print("Invalid amount!");
      }
    } else if (choice == '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: amount});
        print("Expense added!");
      } else {
        print("Invalid amount!");
      }
    } else if (choice == '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;

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

      if (net >= 0) {
        print("Net profit: \$${net}");
        double tax = net > 0 ? net * 0.15 : 0;
        if (tax > 0) {
          print("Tax to be paid: \$${tax}");
        }
      } else {
        print("Net loss: \$${-net}");
      }
    } else if (choice == '4') {
      print("Exiting the application. Goodbye!");
      break;
    } else {
      print("Invalid choice. Try again.");
    }
  }
}