// Budget Management Application Code
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? input = stdin.readLineSync();

    if (input == null) {
      print('Invalid input. Please try again.');
      continue;
    }

    int? choice = int.tryParse(input);

    if (choice == null) {
      print('Invalid input. Please enter a number.');
      continue;
    }

    switch (choice) {
      case 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.');
          }
        }
        break;
      case 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.');
          }
        }
        break;
      case 3:
        double totalIncome = incomeList.fold(0, (prev, item) => prev + item.values.first);
        double totalExpenses = expenseList.fold(0, (prev, item) => prev + item.values.first);
        double netProfit = totalIncome - totalExpenses;

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

        if (netProfit >= 0) {
          print('Net profit: \$${netProfit.toStringAsFixed(2)}');
          double tax = netProfit > 0 ? netProfit * 0.15 : 0;
          print('Tax to be paid: \$${tax.toStringAsFixed(2)}');
        } else {
          print('Net loss: \$${(-netProfit).toStringAsFixed(2)}');
        }
        break;
      case 4:
        print('Exiting the application. Goodbye!');
        return;
      default:
        print('Invalid choice. Please select a valid option.');
    }
  }
}