ATM.java

public class ATM{
    private boolean userAuthenticated;
    private int currentAccountNumber;
    private Screen screen;
    private Keypad keypad;
    private CashDispenser cashDispenser;
    private DepositSlot depositSlot;
    private BankDatabase bankDatabase;

    private static final int BALANCE_INQUIRY = 1;
    private static final int WITHDRAWAL = 2;
    private static final int DEPOSIT = 3;
    private static final int EXIT = 4;

    public ATM(){
        userAuthenticated = false;
        currentAccountNumber = 0;
        screen = new Screen();
        keypad = new Keypad();
        cashDispenser = new CashDispenser();
        depositSlot = new DepositSlot();
        bankDatabase = new BankDatabase();

    }

    public void run(){
        while(true){
            while(!userAuthenticated){
                screen.displayMessageLine(" \n Welcome");
                authenticateUser();
        
            }

            performTransactions();
            userAuthenticated = false;
            currentAccountNumber = 0;
            screen.displayMessageLine("\n Thank you! Goodbye!");

        }
    }
    private void authenticateUser(){
        screen.displayMessage("\n Please enter your account number:");
        int accountNumber = keypad.getInput();
        screen.displayMessage("\n Enter your PIN:");
        int pin = keypad.getInput();

        userAuthenticated = bankDatabase.authenticateUser(accountNumber, pin);
        
        if(userAuthenticated){
            currentAccountNumber = accountNumber;
        }else{
            screen.displayMessageLine("Invalid account number or PIN. Please try again.");

        }
    }
    private void performTransactions(){
        Transaction currentTransaction = null;
        boolean userExited = false;

        while(!userExited){
            int mainMenuSelection = displayMainMenu();

            switch(mainMenuSelection){
                case BALANCE_INQUIRY:
                case WITHDRAWAL:
                case DEPOSIT:
                    currentTransaction = createTransaction(mainMenuSelection);
                    currentTransaction.execute();
                    break;

                case EXIT:
                    screen.displayMessageLine("\n Exiting the system...");
                    userExited = true;
                    break;

                default:
                    screen.displayMessageLine("\n You did not enter a valid selection. Try again.");
            }
        }
    }

    private int displayMainMenu(){
        screen.displayMessageLine("\n Main Menu");
        screen.displayMessageLine("1 - View my balance");
        screen.displayMessageLine("2 - Withdraw Cash");
        screen.displayMessageLine("3- Deposit Funds");
        screen.displayMessageLine("Exit \n");

        return keypad.getInput();
    }

    private Transaction createTransaction(int type)
    {
        Transaction temp = null;
        switch(type){
            case BALANCE_INQUIRY:
                temp = new BalanceInquiry(currentAccountNumber, screen, bankDatabase);
                break;
            case WITHDRAWAL:
                temp = new Withdrawal(currentAccountNumber, screen, bankDatabase, keypad, cashDispenser);
                break;
            case DEPOSIT:
                temp = new Deposit(currentAccountNumber, screen, bankDatabase, keypad, depositSlot); 
                break;
        }
        return temp;

    }
}