Untitled

import java.util.ArrayList;
import java.util.Scanner;

// User class
class User {
    private String username;
    private String password;

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

    public String getUsername() {
        return username;
    }

    public boolean checkPassword(String password) {
        return this.password.equals(password);
    }
}

// Note class
class Note {
    private String content;
    private boolean isSecure;

    public Note(String content, boolean isSecure) {
        this.content = content;
        this.isSecure = isSecure;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public boolean isSecure() {
        return isSecure;
    }

    @Override
    public String toString() {
        return (isSecure ? "[Secured] " : "") + content;
    }
}

// Main application class
public class NoteTakingApp {
    private static ArrayList<User> users = new ArrayList<>();
    private static User loggedInUser = null;
    private static ArrayList<Note> notes = new ArrayList<>();

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("1. Sign In");
            System.out.println("2. Log In");
            System.out.println("3. Exit");
            System.out.print("Choose an option: ");
            int choice = scanner.nextInt();
            scanner.nextLine(); // Consume newline

            switch (choice) {
                case 1:
                    signIn(scanner);
                    break;
                case 2:
                    login(scanner);
                    break;
                case 3:
                    System.out.println("Exiting...");
                    return;
                default:
                    System.out.println("Invalid option. Try again.");
            }
        }
    }

    private static void signIn(Scanner scanner) {
        System.out.print("Enter username: ");
        String username = scanner.nextLine();

        System.out.print("Enter password: ");
        String password = scanner.nextLine();

        System.out.print("Confirm password: ");
        String confirmPassword = scanner.nextLine();

        if (!password.equals(confirmPassword)) {
            System.out.println("Passwords do not match.");
            return;
        }

        if (!validatePassword(password)) {
            System.out.println("Password must be 6+ characters with uppercase, lowercase, and a special character.");
            return;
        }

        users.add(new User(username, password));
        System.out.println("User created successfully!");
    }

    private static void login(Scanner scanner) {
        System.out.print("Enter username: ");
        String username = scanner.nextLine();

        System.out.print("Enter password: ");
        String password = scanner.nextLine();

        for (User user : users) {
            if (user.getUsername().equals(username) && user.checkPassword(password)) {
                loggedInUser = user;
                System.out.println("Login successful!");
                manageNotes(scanner);
                return;
            }
        }

        System.out.println("Invalid username or password.");
    }

    private static void manageNotes(Scanner scanner) {
        while (true) {
            System.out.println("1. Add Note");
            System.out.println("2. View Notes");
            System.out.println("3. Update Note");
            System.out.println("4. Delete Note");
            System.out.println("5. Logout");
            System.out.print("Choose an option: ");
            int choice = scanner.nextInt();
            scanner.nextLine(); // Consume newline

            switch (choice) {
                case 1:
                    System.out.print("Enter your note: ");
                    String content = scanner.nextLine();
                    System.out.print("Is this note secure? (yes/no): ");
                    boolean isSecure = scanner.nextLine().equalsIgnoreCase("yes");
                    notes.add(new Note(content, isSecure));
                    System.out.println("Note added successfully!");
                    break;
                case 2:
                    System.out.println("Your Notes:");
                    for (int i = 0; i < notes.size(); i++) {
                        System.out.println((i + 1) + ". " + notes.get(i));
                    }
                    break;
                case 3:
                    System.out.print("Enter the note number to update: ");
                    int updateIndex = scanner.nextInt() - 1;
                    scanner.nextLine(); // Consume newline
                    if (updateIndex >= 0 && updateIndex < notes.size()) {
                        System.out.print("Enter the new content: ");
                        String newContent = scanner.nextLine();
                        notes.get(updateIndex).setContent(newContent);
                        System.out.println("Note updated successfully!");
                    } else {
                        System.out.println("Invalid note number.");
                    }
                    break;
                case 4:
                    System.out.print("Enter the note number to delete: ");
                    int deleteIndex = scanner.nextInt() - 1;
                    scanner.nextLine(); // Consume newline
                    if (deleteIndex >= 0 && deleteIndex < notes.size()) {
                        notes.remove(deleteIndex);
                        System.out.println("Note deleted successfully!");
                    } else {
                        System.out.println("Invalid note number.");
                    }
                    break;
                case 5:
                    System.out.println("Logged out.");
                    loggedInUser = null;
                    return;
                default:
                    System.out.println("Invalid option. Try again.");
            }
        }
    }

    private static boolean validatePassword(String password) {
        if (password.length() < 6) return false;
        boolean hasUppercase = false;
        boolean hasLowercase = false;
        boolean hasSpecial = false;

        for (char c : password.toCharArray()) {
            if (Character.isUpperCase(c)) hasUppercase = true;
            else if (Character.isLowerCase(c)) hasLowercase = true;
            else if (!Character.isLetterOrDigit(c)) hasSpecial = true;
        }

        return hasUppercase && hasLowercase && hasSpecial;
    }
}