import 'dart:io'; // Required to read user input

void main() {
  // Welcome message
  print('Welcome to the Budget Management Application!');

  // Lists to store income and expenses
  List<Map<String, double>> incomeList = [];
  List<Map<String, double>> expenseList = [];

  while (true) {
    // Display menu options
    print('\nChoose an option:');
    print('1. Add Income');
    print('2. Add Expense');
    print('3. View Summary');
    print('4. Exit');

    String? choice = stdin.readLineSync();

    switch (choice) {
      case '1':
        // Add income
        print('Enter income description:');
        String? desc = stdin.readLineSync();

        double? amount;
        do {
          print('Enter amount (positive number only):');
          String? amtInput = stdin.readLineSync();
          amount = double.tryParse(amtInput ?? '');
          if (amount == null || amount <= 0) {
            print('Invalid amount. Please try again.');
            amount = null;
          }
        } while (amount == null);

        incomeList.add({desc ?? 'Unnamed Income': amount});
        print(
          'Income added: ${desc ?? "Unnamed Income"} with amount \$${amount}',
        );
        break;

      case '2':
        // Add expense
        print('Enter expense description:');
        String? descExp = stdin.readLineSync();

        double? amountExp;
        do {
          print('Enter amount (positive number only):');
          String? amtInputExp = stdin.readLineSync();
          amountExp = double.tryParse(amtInputExp ?? '');
          if (amountExp == null || amountExp <= 0) {
            print('Invalid amount. Please try again.');
            amountExp = null;
          }
        } while (amountExp == null);

        expenseList.add({descExp ?? 'Unnamed Expense': amountExp});
        print(
          'Expense added: ${descExp ?? "Unnamed Expense"} with amount \$${amountExp}',
        );
        break;

      case '3':
        // View summary
        double totalIncome = 0;
        double totalExpense = 0;

        for (var item in incomeList) {
          totalIncome += item.values.first;
        }
        for (var item in expenseList) {
          totalExpense += item.values.first;
        }

        double netProfit = totalIncome - totalExpense;
        double tax = netProfit > 0 ? netProfit * 0.15 : 0;

        print('\n=== Financial Summary ===');
        print('Total Income: \$${totalIncome}');
        print('Total Expenses: \$${totalExpense}');

        if (netProfit > 0) {
          print('Net Profit: \$${netProfit}');
          print('Tax (15%): \$${tax}');
        } else if (netProfit < 0) {
          print('Net Loss: \$${-netProfit}');
        } else {
          print('No profit or loss.');
        }
        break;

      case '4':
        print('Exiting program...');
        return;

      default:
        print('Invalid choice. Please try again.');
    }
  }
}