import 'dart:io';

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

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

  while (true) {
    print("\nPlease choose an option:");
    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 == "1") {
      stdout.write("Enter income description: ");
      String? description = stdin.readLineSync();

      stdout.write("Enter income amount: ");
      double? amount = double.tryParse(stdin.readLineSync() ?? "");

      if (description != null && description.isNotEmpty && amount != null && amount > 0) {
        incomeList.add({"description": description, "amount": amount});
        print("Income added!");
      } else {
        print("Invalid input! Description cannot be empty and amount must be a positive number.");
      }

    } else if (choice == "2") {
      stdout.write("Enter expense description: ");
      String? description = stdin.readLineSync();

      stdout.write("Enter expense amount: ");
      double? amount = double.tryParse(stdin.readLineSync() ?? "");

      if (description != null && description.isNotEmpty && amount != null && amount > 0) {
        expenseList.add({"description": description, "amount": amount});
        print("Expense added!");
      } else {
        print("Invalid input! Description cannot be empty and amount must be a positive number.");
      }

    } else if (choice == "3") {
      double totalIncome = 0;
      for (var item in incomeList) {
        totalIncome += item["amount"];
      }

      double totalExpenses = 0;
      for (var item in expenseList) {
        totalExpenses += item["amount"];
      }

      double netResult = totalIncome - totalExpenses;
      bool isProfit = netResult > 0;

      print("\nSummary:");
      print("Total income: \$${totalIncome.toStringAsFixed(0)}");
      print("Total expenses: \$${totalExpenses.toStringAsFixed(0)}");

      if (isProfit) {
        print("Net profit: \$${netResult.toStringAsFixed(0)}");
      } else if (netResult < 0) {
        print("Net loss: \$${(-netResult).toStringAsFixed(0)}");
      } else {
        print("Net result: \$0 (Break even)");
      }

      // Tax calculation using ternary operator - only if profitable
      double tax = isProfit ? netResult * 0.15 : 0;
      if (isProfit) {
        print("Tax to be paid: \$${tax.toStringAsFixed(0)}");
      }

    } else if (choice == "4") {
      print("Exiting the application. Goodbye!");
      return;

    } else {
      print("Invalid choice. Please try again.");
    }
  }
}