import 'dart:io';

void main() {
  BudgetManager().run();
}

class BudgetManager {
  final List<Map<String, dynamic>> _incomes = [];
  final List<Map<String, dynamic>> _expenses = [];

void run() {
  print('Welcome to the Budget Management Application!');

  while (true) {
    _displayMenu();
    String? choice = stdin.readLineSync();

    switch (choice) {
      case '1':
      _addIncome();
      break;
      case '2':
      _addExpense();
      break;
      case '3':
      _viewSummary();
      break;
  case '4':
    print('Exiting the application. Goodbye!');
    return;
  default:
  print('Invalid choice. Please try again.');

   }
  }
}

void _displayMenu() {
  print('\nPlease choose an option:');
  print('1. Add income');
  print('2. Add expense');
  print('3. View summary');
  print('4. Exit');
  print('\nEnter your choice:');
}

void _addIncome() {
  print('Enter income description:');
  String? description = stdin.readLineSync();

  print('Enter income amount:');
  String? amountInput = stdin.readLineSync();

  try {
    double amount = double.parse(amountInput!);
    
    if (amount > O) {
      _incomes.add ({
        'desciption': desciption ?? 'Unknown',
        'amount': amount
      });
      print('Income added!');
    } else {
      print('Amount must be positive.');
    }
  } catch (e) {
    print('Invalid amount. Please enter a valid number .');
  }
}

void _addExpense() {
  print('Enter expense description: ');
  String? desciption = stdin.readLineSync();

 print('Enter expense amount: ');
 String? amountInput = stdin.readLineSync();

 try {
   double amount = double.parse(amountInput!);

   if (amount > O) {
    _expenses.add({
      'description': desciption ?? 'Unknown',
      'amount': amount 
    });
    print('Expense added!');
   } else {
    print('Amount must be positive.');
   }
 } catch (e) {
print('Invalid amount. Please enter a valid number .');
 
 }
}

valid _viewSummary() {
  double totalIncome = _caIcuIateTotal(_incomes);
  double totalExpenses = _caIcuIateTotal(_expenses);
  double net = totalIncome - totalExpenses;

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

  if (net >= O) {
    print('Net profit: \$${net.toStringAsFixed(2)}');

    // Tax calculation using ternary operator
    double tax = net > O ? net *O.15 : O;
    if (tax > O) {
      print('Tax to be paid: \$${tax.toStringAsFixed(2)}');
    }
   } else {
     print('Net loss: \$${net.abs().toStringAsFixed(2)}');
   }
}

double _caIcuIateTotal(List<Map<String, dynamic>> items) {
   double total = O;
   for (var item in items) {
    total += item['amount'];
  }
  return total; 
  
 }
}