import 'dart:io';

List<Map<String, dynamic>> incomeEntries = [];
List<Map<String, dynamic>> expenseEntries = [];

void addEntry(List<Map<String, dynamic>> entries, String type) {
  stdout.write("Enter $type description: ");
  String description = stdin.readLineSync() ?? 'N/A';
  
  stdout.write("Enter $type amount: ");
  String? amountInput = stdin.readLineSync();
  
  double? amount = double.tryParse(amountInput ?? '');
  
  if (amount != null && amount >= 0) {
    entries.add({'description': description, 'amount': amount});
    print("${type.substring(0, 1).toUpperCase()}${type.substring(1)} added!");
  } else {
    print("Invalid amount. Please enter a valid non-negative number.");
  }
}

void viewSummary() {
  double totalIncome = incomeEntries.fold(0.0, (sum, entry) => sum + entry['amount']);
  double totalExpenses = expenseEntries.fold(0.0, (sum, entry) => sum + entry['amount']);
  
  double netProfit = totalIncome - totalExpenses;
  
  double tax = netProfit > 0 ? netProfit * 0.15 : 0.0;
  
  print("\n--- Financial Summary ---");
  print("Total Income: \$${totalIncome.toStringAsFixed(2)}");
  print("Total Expenses: \$${totalExpenses.toStringAsFixed(2)}");

  if (netProfit >= 0) {
    print("Net Profit: \$${netProfit.toStringAsFixed(2)}");
    
    if (netProfit > 0) {
        print("Tax to be paid (15%): \$${tax.toStringAsFixed(2)}");
    }
    
  } else {
    print("Net Loss: \$${(netProfit * -1).toStringAsFixed(2)}");
  }
}

void main() {
  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();

    switch (choice) {
      case '1':
        addEntry(incomeEntries, 'income');
        break;
      case '2':
        addEntry(expenseEntries, 'expense');
        break;
      case '3':
        viewSummary();
        break;
      case '4':
        print("Exiting the application. Goodbye!");
        return;
      default:
        print("Invalid choice. Please enter a number between 1 and 4.");
    }
  }
}