User.java

import java.util.*;

public class User {

    // Storing user details
    String username;  // The username of the user
    String password;  // The password of the user (not encrypted in this simple example)
    List<Tweet> tweets;  // A list to store all the tweets made by the user
    Set<String> following;  // A set to store the usernames of users that the current user is following
    Set<String> followers;  // A set to store the usernames of users that follow the current user

    // Constructor to initialize a new user with a username and password
    public User(String username, String password) {
        this.username = username;  // Assign the username for the user
        this.password = password;  // Assign the password for the user
        this.tweets = new ArrayList<>();  // Initialize the list to store tweets
        this.following = new HashSet<>();  // Initialize the set of users the user is following
        this.followers = new HashSet<>();  // Initialize the set of users who are following the user
    }

    // Method to post a new tweet
    public void postTweet(String message) {
        Tweet newTweet = new Tweet(username, message);
        tweets.add(newTweet);
    }

    // Method to display all tweets by this user
    public void displayTweets() {
        // If the user has no tweets, print a message saying so
        if (tweets.isEmpty()) {
            System.out.println("No tweets found for user @" + username);
        } else {
            // Loop through all tweets and show each one
            for (Tweet tweet : tweets) {
                tweet.displayTweet();
            }
        }
    }

    // Method to follow another user
    public void followUser(String username) {
        following.add(username);
    }

    // Method to add a follower to the current user
    public void addFollower(String username) {
        followers.add(username);
    }

    // Method to check if the user is following another user
    public boolean isFollowing(String username) {
        return following.contains(username);
    }

    // Method to check if the user is followed by another user
    public boolean isFollowedBy(String username) {
        return followers.contains(username);
    }

    // Method for the user to like a tweet
    public void likeTweet(Tweet tweet) {
        tweet.addLike(username);
    }
}