import java.util.ArrayList;

public class Phone {
    private String number;
    private ArrayList<String> messages;

    Phone(String number) throws NumberInUseException {
        this.number = number;
        this.messages = new ArrayList<String>();
        Network.instance().register(this);
    }

    String getNumber() {
        return this.number;
    }

    void sendTextToFriend(String friendsNumber, String messageForThem)
        throws NonWorkingNumberException, MailboxFullException {
        Network.instance().deliverText(friendsNumber, messageForThem);
    }

    void acceptTextFromNetwork(String messageForMe)
        throws MailboxFullException {
        if (this.messages.size() >= 5) {
            throw new MailboxFullException();
        } else {
            this.messages.add(messageForMe);
        }
    }

    String viewNextText() {
        if (messages.size() == 0) {
            return "";
        } else {
            String message = this.messages.get(0);
            this.messages.remove(0);
            return message;
        }
    }
}