public class Main {
public static void main(String[] args) {
    ToDoEngine engine = new ToDoEngine();
    engine.displayMainMenu();
    engine.displayUserMenu();
    }
}

import java.util.HashMap;
import java.util.Scanner;

public class AccountMaker {

private HashMap<String, User> loginDetails = new HashMap<>();
private String login, password;
private Scanner input = new Scanner(System.in);


void inputLoginAndPassword() {
    System.out.println("Input your login");
    login = input.next();

    System.out.println("Input your password");
    password = input.next();
}

void createAccount() throws InterruptedException {
    User newUser = new User(login, password);
    loginDetails.put(login, newUser);
    System.out.println("Account has been created successfully");
    Thread.sleep(2000);
}

HashMap<String, User> getLoginDetails() {
    return loginDetails;
}

}

import java.util.Scanner;

public class AccountLogger {

private AccountMaker accountMaker;
private Scanner input = new Scanner(System.in);
private String login, password;


AccountLogger(AccountMaker accountMaker) {
    this.accountMaker = accountMaker;
}


void inputLoginAndPassword() {
    System.out.println("Input your login");
    login = input.next();

    System.out.println("Input your password");
    password = input.next();
}

boolean isLoginDataIncorrect() {
    User user = accountMaker.getLoginDetails().get(login);
    try {
        if (user.getPassword().equals(password)) {
            System.out.println("You've logged in.");
            return false;
        } else {
            System.out.println("Bad login or password");
        }
    } catch (NullPointerException e) {
        System.out.println("Bad login or password");
    }
    return true;
}
}

public class User {
private Tasker tasker;
private String login;
private String password;

User(String login, String password) {
    this.login = login;
    this.password = password;
}

User(Tasker tasks) {
    this.tasker = tasks;
}

void addNewTask(String task) {
    tasker.createTask(task);
}

void deleteTask(String task) {
    tasker.deleteTask(task);
}

void showAllTasks() {
    tasker.showAllTasks();
}

String getPassword() {
    return password;
}

}

import java.util.ArrayList;
import java.util.List;

public class Tasker {

private List<String> listOfTasks = new ArrayList<>();


void createTask(String task) {
    listOfTasks.add(task);
}

void deleteTask(String task) {
    listOfTasks.remove(task);
}

void showAllTasks() {
    for (String listOfTask : listOfTasks) {
        System.out.println(listOfTask);
    }
}
}

import java.util.InputMismatchException;
import java.util.Scanner;

public class ToDoEngine {

private Scanner input = new Scanner(System.in);
private AccountMaker accountMaker = new AccountMaker();
private AccountLogger accountLogger = new AccountLogger(accountMaker);
private boolean loopIsTrue = true;
private Tasker tasks = new Tasker();
private User user = new User(tasks);

void displayMainMenu() {
    System.out.println("What do you wanna to do?");
    System.out.println("1. Add Account 2. Log into my account");

    while (loopIsTrue) {
        try {
            getOptionsOfMainMenu(input.nextInt());
        } catch (InputMismatchException e) {
            System.out.println("You've inputed something wrong!");
            System.out.println("What do you wanna to do?");
            System.out.println("1. Add Account 2. Log into my account");
            input.next();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

private void getOptionsOfMainMenu(int option) throws InterruptedException {
    if (option >= 1 && option <= 2) {
        switch (option) {
            case 1:
                accountMaker.inputLoginAndPassword();
                accountMaker.createAccount();
                System.out.println("Now let's log into you account.");
            case 2:
                while (loopIsTrue) {
                    accountLogger.inputLoginAndPassword();
                    if (!accountLogger.isLoginDataIncorrect()) {
                        loopIsTrue = false;
                    }
                }
                break;
        }
    }
}

public void displayUserMenu() {
    loopIsTrue = true;
    while (loopIsTrue) {
        System.out.println("What do you wanna to do?");
        System.out.println("1. Add task 2. Show my tasks 3. Delete task 4. Exit");
        getOptionsOfUserMenu(input.nextInt());
    }
}

private void getOptionsOfUserMenu(int option) {
    if (option >= 1 && option <= 4) {
        switch (option) {
            case 1:
                System.out.println("Write down your task.");
                input.nextLine();
                user.addNewTask(input.nextLine());
                System.out.println("Task was added.");
                break;
            case 2:
                System.out.println("----------------");
                System.out.println("YOUR TASK LIST:");
                user.showAllTasks();
                System.out.println("----------------");
                break;
            case 3:
                System.out.println("Write down your task that you want to delete from task list.");
                input.nextLine();
                user.deleteTask(input.nextLine());
                System.out.println("Task was deleted");
                loopIsTrue = false;
                break;
            case 4:
                loopIsTrue = false;
                break;
        }
    }
}
}