// budget_app.dart
import 'dart:io';

void main() {
  List<Map<String, dynamic>> incomeList = [];
  List<Map<String, dynamic>> expenseList = [];
  bool running = true;

  while (running) {
    print('\nWelcome to the Budget Management Application!');
    print('Please choose an option:');
    print('1. Add income');
    print('2. Add expense');
    print('3. View summary');
    print('4. Exit');
    stdout.write('\nEnter your choice: ');
    String? choice = stdin.readLineSync();

    if (choice == null) continue;

    if (choice == '1') {
      stdout.write('Enter income description: ');
      String? desc = stdin.readLineSync() ?? 'Income';
      stdout.write('Enter income amount: ');
      String? amtStr = stdin.readLineSync();
      double? amt = double.tryParse(amtStr ?? '');
      if (amt == null || amt < 0) {
        print('Invalid amount. Must be a non-negative number.');
      } else {
        incomeList.add({'description': desc, 'amount': amt});
        print('Income added!');
      }
    } else if (choice == '2') {
      stdout.write('Enter expense description: ');
      String? desc = stdin.readLineSync() ?? 'Expense';
      stdout.write('Enter expense amount: ');
      String? amtStr = stdin.readLineSync();
      double? amt = double.tryParse(amtStr ?? '');
      if (amt == null || amt < 0) {
        print('Invalid amount. Must be a non-negative number.');
      } else {
        expenseList.add({'description': desc, 'amount': amt});
        print('Expense added!');
      }
    } else if (choice == '3') {
      double totalIncome = incomeList.fold(0.0, (p, e) => p + (e['amount'] as double));
      double totalExpenses = expenseList.fold(0.0, (p, e) => p + (e['amount'] as double));
      double net = totalIncome - totalExpenses;
      print('\nSummary:');
      print('Total income: \$${totalIncome.toStringAsFixed(2)}');
      print('Total expenses: \$${totalExpenses.toStringAsFixed(2)}');
      if (net >= 0) {
        print('Net profit: \$${net.toStringAsFixed(2)}');
      } else {
        print('Net loss: \$${(-net).toStringAsFixed(2)}');
      }
      // Optional tax: 15% if profit (ternary)
      double tax = net > 0 ? net * 0.15 : 0.0;
      print('Tax to be paid: \$${tax.toStringAsFixed(2)}');
    } else if (choice == '4') {
      print('Exiting the application. Goodbye!');
      running = false;
    } else {
      print('Invalid choice. Please choose 1-4.');
    }
  }
}