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? description = stdin.readLineSync();
      stdout.write('Enter income amount: ');
      String? amountInput = stdin.readLineSync();
      if (description != null && amountInput != null) {
        double? amount = double.tryParse(amountInput);
        if (amount != null && amount > 0) {
          incomeList.add({description: amount});
          print('Income added!');
        } else {
          print('Invalid amount. Please enter a positive number.');
        }
      }
    } else if (choice == '2') {
      stdout.write('Enter expense description: ');
      String? description = stdin.readLineSync();
      stdout.write('Enter expense amount: ');
      String? amountInput = stdin.readLineSync();
      if (description != null && amountInput != null) {
        double? amount = double.tryParse(amountInput);
        if (amount != null && amount > 0) {
          expenseList.add({description: amount});
          print('Expense added!');
        } else {
          print('Invalid amount. Please enter a positive number.');
        }
      }
    } else if (choice == '3') {
      double totalIncome = incomeList.fold(0, (prev, element) => prev + element.values.first);
      double totalExpenses = expenseList.fold(0, (prev, element) => prev + element.values.first);
      double netProfit = totalIncome - totalExpenses;

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

      if (netProfit >= 0) {
        print('Your net profit is \$${netProfit.toStringAsFixed(2)}');
        double tax = netProfit > 0 ? netProfit * 0.15 : 0;
        print('Tax to be paid: \$${tax.toStringAsFixed(2)}');
      } else {
        print('Your net loss is \$${(-netProfit).toStringAsFixed(2)}');
      }
    } else if (choice == '4') {
      print('Exiting the application. Goodbye!');
      break;
    } else {
      print('Invalid choice. Please try again.');
    }
  }
}