package mediator;

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

/**
 * Concrete Mediator — the chat room that routes messages between users.
 * Users talk to ChatRoom; ChatRoom talks to users. Nobody else talks to anybody.
 */
public class ChatRoom implements ChatMediator {
    private final List<User> users = new ArrayList<>();

    @Override
    public void addUser(User user) {
        users.add(user);
        System.out.println("  [ChatRoom] " + user.getName() + " joined the room");
    }

    @Override
    public void sendMessage(String message, User sender) {
        for (User user : users) {
            if (user != sender) {  // don't echo back to sender
                user.receive(message, sender.getName());
            }
        }
    }
}