import 'dart:io';

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

  while (true) {
    print("\n=== BUDGET MANAGEMENT MENU ===");
    print("1. Add Income");
    print("2. Add Expense");
    print("3. View Summary (Profit / Loss)");
    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 successfully!");
      } else {
        print("Invalid amount. Try again.");
      }

    } 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 successfully!");
      } else {
        print("Invalid amount. Try again.");
      }

    } else if (choice == "3") {
      double totalIncome = 0;
      double totalExpenses = 0;

      for (var item in incomeList) {
        totalIncome += item.values.first;
      }
      for (var item in expenseList) {
        totalExpenses += item.values.first;
      }

      double netResult = totalIncome - totalExpenses;

      print("\n=== BUDGET SUMMARY ===");
      print("Total Income: $totalIncome SAR");
      print("Total Expenses: $totalExpenses SAR");
      print(netResult >= 0
          ? "Your net profit is ${netResult.toStringAsFixed(2)} SAR"
          : "Your net loss is ${(-netResult).toStringAsFixed(2)} SAR");

      // Optional tax feature
      double tax = netResult > 0 ? netResult * 0.15 : 0;
      if (tax > 0) {
        print("Tax to pay (15%): ${tax.toStringAsFixed(2)} SAR");
      }

    } else if (choice == "4") {
      print("Exiting program. Goodbye!");
      return;

    } else {
      print("Invalid choice. Try again.");
    }
  }
}