import 'dart:io';

void main() {
  print('Welcome to Budget Manager CLI!\n');

  List<Map<String, dynamic>> incomeList = [];
  List<Map<String, dynamic>> expenseList = [];

  bool running = true;

  while (running) {
    print('\nMenu:');
    print('1. Add Income');
    print('2. Add Expense');
    print('3. View Summary');
    print('4. Exit');

    stdout.write('Choose an option (1-4): ');
    String choice = (stdin.readLineSync() ?? '').trim();

    if (choice == '1') {
      _addEntry(incomeList, isIncome: true);
    } else if (choice == '2') {
      _addEntry(expenseList, isIncome: false);
    } else if (choice == '3') {
      _viewSummary(incomeList, expenseList);
    } else if (choice == '4') {
      running = false;
      print('Exiting Budget Manager. Goodbye!');
    } else {
      print('Invalid choice. Enter 1, 2, 3, or 4.');
    }
  }
}

void _addEntry(List<Map<String, dynamic>> list, {required bool isIncome}) {
  String type = isIncome ? 'income' : 'expense';
  stdout.write('Enter $type description: ');
  String desc = (stdin.readLineSync() ?? '').trim();

  if (desc.isEmpty) {
    print('Description cannot be empty. Aborting.');
    return;
  }

  stdout.write('Enter amount for "$desc": ');
  String amtRaw = (stdin.readLineSync() ?? '').trim();
  double? amount = double.tryParse(amtRaw);

  if (amount == null) {
    print('Invalid amount. Please enter a numeric value.');
    return;
  }
  if (amount < 0) {
    print('Amount cannot be negative.');
    return;
  }

  list.add({'description': desc, 'amount': amount});
  print('${isIncome ? "Income" : "Expense"} added: "$desc" — \$${amount.toStringAsFixed(2)}');
}

void _viewSummary(List<Map<String, dynamic>> incomes, List<Map<String, dynamic>> expenses) {
  double totalIncome = 0.0;
  double totalExpenses = 0.0;

  for (var entry in incomes) {
    var amt = entry['amount'];
    if (amt is num) totalIncome += amt.toDouble();
  }

  for (var entry in expenses) {
    var amt = entry['amount'];
    if (amt is num) totalExpenses += amt.toDouble();
  }

  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)}');
    double tax = net > 0 ? net * 0.15 : 0.0;
    print(tax > 0 ? 'Tax to pay (15%): \$${tax.toStringAsFixed(2)}' : 'No tax to be paid.');
  } else {
    print('Your net loss is \$${(net.abs()).toStringAsFixed(2)}');
    print('No tax (losses do not incur tax).');
  }

  if (incomes.isNotEmpty) {
    print('\nIncome entries:');
    for (var e in incomes) {
      print('- ${e['description']}: \$${(e['amount'] as num).toStringAsFixed(2)}');
    }
  } else {
    print('\nNo income entries.');
  }

  if (expenses.isNotEmpty) {
    print('\nExpense entries:');
    for (var e in expenses) {
      print('- ${e['description']}: \$${(e['amount'] as num).toStringAsFixed(2)}');
    }
  } else {
    print('\nNo expense entries.');
  }

  print('-----------------------');
}