import 'dart:io';

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

// تعريف ثابت للضريبة (Optional)
const double TAX_RATE = 0.15; // 15% ضريبة [cite: 100]

// دالة لحساب المجموع الكلي من قائمة (دخل أو مصروفات)
double _calculateTotal(List<Map<String, dynamic>> list) {
  return list.fold(0.0, (sum, item) => sum + item['amount']);
}

double? _getAmountInput(String prompt) {
  stdout.write(prompt);
  String? input = stdin.readLineSync();
  double? amount = double.tryParse(input ?? "");

  if (amount == null || amount <= 0) {
    print("Invalid input. Please enter a valid positive numeric amount");
    return null;
  }
  return amount;
}

void main() {
  print("Welcome to the Budget Management Application!");

  while (true) {
    print("\n\nPlease choose an option:");
    print("1. Add Income");
    print("2. Add Expense");
    print("3. View Summary (Net Profit/Loss)");
    print("4. Exit");
    stdout.write("Enter your choice: ");

    String? choice = stdin.readLineSync();

    if (choice == null || choice.isEmpty) {
      print("Invalid input. Please enter a number from 1 to 4.");
      continue;
    }

    switch (choice) {
      case "1":
        stdout.write("Enter income description: ");
        String? description = stdin.readLineSync();

        double? amount = _getAmountInput("Enter income amount: \$");

        if (description != null && description.isNotEmpty && amount != null) {
          incomeList.add({'description': description, 'amount': amount});
          print("Income added successfully!");
        }
        break;

      case "2":
        stdout.write("Enter expense description: ");
        String? description = stdin.readLineSync();

        double? amount = _getAmountInput("Enter expense amount: \$");

        if (description != null && description.isNotEmpty && amount != null) {
          expenseList.add({'description': description, 'amount': amount});
          print("Expense added successfully!");
        }
        break;

      case "3":
        double totalIncome = _calculateTotal(incomeList);
        double totalExpenses = _calculateTotal(expenseList);
        double netProfitLoss = totalIncome - totalExpenses;

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

        if (netProfitLoss > 0) {
          double taxAmount = 0.0;

          taxAmount = netProfitLoss > 0 ? netProfitLoss * TAX_RATE : 0.0;

          print("Net Profit: \$${netProfitLoss.toStringAsFixed(2)}");

          print("Tax to be paid (15%): \$${taxAmount.toStringAsFixed(2)}");
        } else if (netProfitLoss < 0) {
          print("Net Loss: -\$${(-netProfitLoss).toStringAsFixed(2)}");
        } else {
          print("Net Result: \$0.00 (Break Even)");
        }
        print("------------------------------");
        break;

      case "4":
        print("Exiting the application. Goodbye!");
        return;

      default:
        print("Invalid choice. Please select a number from 1 to 4");
    }
  }
}