// =======================================
// Budget Management Application
// Developer: Ahmed Alawazim
// Student ID: 2021204738
// =======================================

import 'dart:io';

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

  while (true) {
    print('\n=======================================');
    print(' Welcome to the Budget Management Application! ');
    print(' Developer: Ahmed Alawazim');
    print(' Student ID: 2021204738');
    print('=======================================');
    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 == '1') {
      // Add Income
      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) {
        print('Invalid amount! Please enter a positive number.');
      } else {
        incomeList.add({desc ?? 'Income': amount});
        print('Income added successfully!');
      }
    } else if (choice == '2') {
      // Add Expense
      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) {
        print('Invalid amount! Please enter a positive number.');
      } else {
        expenseList.add({desc ?? 'Expense': amount});
        print('Expense added successfully!');
      }
    } else if (choice == '3') {
      // View Summary
      double totalIncome = 0;
      double totalExpenses = 0;

      for (var i in incomeList) {
        i.forEach((key, value) => totalIncome += value);
      }
      for (var e in expenseList) {
        e.forEach((key, value) => totalExpenses += value);
      }

      double net = totalIncome - totalExpenses;

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

      if (net > 0) {
        print('Your net profit is \$${net.toStringAsFixed(2)}');

        // Optional Tax Feature
        double tax = net * 0.15;
        print('Tax to be paid (15%): \$${tax.toStringAsFixed(2)}');
        print('Net profit after tax: \$${(net - tax).toStringAsFixed(2)}');
      } else if (net < 0) {
        print('Your net loss is \$${net.abs().toStringAsFixed(2)}');
      } else {
        print('You broke even — no profit or loss.');
      }
    } else if (choice == '4') {
      print('Exiting Budget Management Application. Goodbye!');
      break;
    } else {
      print('Invalid choice! Please enter a number between 1 and 4.');
    }
  }
}