import 'dart:io';

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

  // Lists to store income and expenses
  List<Map<String, double>> incomeList = [];
  List<Map<String, double>> expenseList = [];

  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 (1-4): ");
    String? choice = stdin.readLineSync();

    if (choice == '1') {
      // Add income
      stdout.write("Enter income description: ");
      String? description = stdin.readLineSync();

      double? amount;
      while (true) {
        stdout.write("Enter income amount: ");
        String? inputAmount = stdin.readLineSync();
        if (inputAmount != null && double.tryParse(inputAmount) != null) {
          amount = double.parse(inputAmount);
          if (amount >= 0) {
            break;
          } else {
            print("Amount cannot be negative. Try again.");
          }
        } else {
          print("Invalid number. Please enter a valid numeric amount.");
        }
      }

      incomeList.add({description!: amount});
      print("Income added successfully!");

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

      double? amount;
      while (true) {
        stdout.write("Enter expense amount: ");
        String? inputAmount = stdin.readLineSync();
        if (inputAmount != null && double.tryParse(inputAmount) != null) {
          amount = double.parse(inputAmount);
          if (amount >= 0) {
            break;
          } else {
            print("Amount cannot be negative. Try again.");
          }
        } else {
          print("Invalid number. Please enter a valid numeric amount.");
        }
      }

      expenseList.add({description!: amount});
      print("Expense added successfully!");

    } else if (choice == '3') {
      // View summary
      double totalIncome = 0;
      double totalExpenses = 0;

      print("\nIncome Summary:");
      if (incomeList.isEmpty) {
        print("No income recorded.");
      } else {
        for (var income in incomeList) {
          income.forEach((desc, amt) {
            print("- $desc: \$${amt.toStringAsFixed(2)}");
            totalIncome += amt;
          });
        }
      }

      print("\nExpense Summary:");
      if (expenseList.isEmpty) {
        print("No expenses recorded.");
      } else {
        for (var expense in expenseList) {
          expense.forEach((desc, amt) {
            print("- $desc: \$${amt.toStringAsFixed(2)}");
            totalExpenses += amt;
          });
        }
      }

      double net = totalIncome - totalExpenses;
      if (net >= 0) {
        print("\nYour net profit is \$${net.toStringAsFixed(2)}");

        // Optional tax calculation: 15% if profit
        double tax = net * 0.15;
        print("Tax to be paid (15%): \$${tax.toStringAsFixed(2)}");
      } else {
        print("\nYour net loss is \$${(-net).toStringAsFixed(2)}");
      }

    } else if (choice == '4') {
      // Exit
      print("Exiting the program. Goodbye!");
      break;
    } else {
      print("Invalid choice. Please enter a number between 1 and 4.");
    }
  }
}