// Dart Program: Budget Management Application
// Author: seham abdullah alduways (ID: 251000905)

import 'dart:io';

void main() {
  List<Map<String, double>> incomeList = [];
  List<Map<String, double>> expenseList = [];

  while (true) {
    print('\n=== Budget Management System ===');
    print('1. Add Income');
    print('2. Add Expense');
    print('3. View Summary');
    print('4. Exit');
    stdout.write('Enter your choice: ');
    String? choice = stdin.readLineSync();

    if (choice == '4') {
      print('Exiting Budget System. Goodbye!');
      break;
    }

    switch (choice) {
      case '1':
        stdout.write('Enter income description: ');
        String? desc = stdin.readLineSync();
        stdout.write('Enter income amount: ');
        double? amount = double.tryParse(stdin.readLineSync() ?? '');
        if (amount != null && amount >= 0) {
          incomeList.add({desc ?? "Income": amount});
          print('Income added successfully.');
        } else {
          print('Invalid amount! Must be positive.');
        }
        break;

      case '2':
        stdout.write('Enter expense description: ');
        String? desc = stdin.readLineSync();
        stdout.write('Enter expense amount: ');
        double? amount = double.tryParse(stdin.readLineSync() ?? '');
        if (amount != null && amount >= 0) {
          expenseList.add({desc ?? "Expense": amount});
          print('Expense added successfully.');
        } else {
          print('Invalid amount! Must be positive.');
        }
        break;

      case '3':
        double totalIncome = incomeList.fold(0, (sum, item) => sum + item.values.first);
        double totalExpenses = expenseList.fold(0, (sum, item) => sum + item.values.first);
        double net = totalIncome - totalExpenses;

        print('\n--- Summary ---');
        print('Total Income: \$${totalIncome.toStringAsFixed(2)}');
        print('Total Expenses: \$${totalExpenses.toStringAsFixed(2)}');

        if (net >= 0) {
          print('Your net profit is \$${net.toStringAsFixed(2)}');
          double tax = net > 0 ? net * 0.15 : 0;
          if (tax > 0) print('Tax to be paid (15%): \$${tax.toStringAsFixed(2)}');
        } else {
          print('Your net loss is \$${net.abs().toStringAsFixed(2)}');
        }
        break;

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