// 소식을 발행하는 발행자에 해당합니다.
@NoArgsConstructor
public class GuppyPublisher extends Observable {

    private static final Logger logger = LoggerFactory.getLogger(GuppyPublisher.class);

    private String name = "Honggu Kang";
    private String company = "ZUM internet";
    private String status = "tired";
    private int age = 29;
    private List<String> skills = Lists.newArrayList("java", "spring", "javascript");


    public void changeJob () {
        this.company = "Kakao corp";
        this.status = "happy";

        this.infoChanged("guppy have a new job.");
    }

    public void newYear () {
        this.age += 1;
        this.status = "sad";

        this.infoChanged("guppy ate 떡국");
    }

    public void addSkill () {
        skills.add("webpack");
        infoChanged("guppy learn new skill");

        skills.add("reactJS");
        infoChanged("guppy learn new skill");

        skills.add("reactive-stream");
        infoChanged("[END] guppy learn new skill");
    }


    // 구독자들에게 소식(이벤트)를 발행합니다.
    public void infoChanged (String msg) {
        super.setChanged();
        // 구독자들에게 소식(이벤트)를 발행합니다.
        super.notifyObservers(msg);
    }

    // 구독자(Observer 객체)들을 추가합니다.
    public void addSubscriber (Observer subscriber) {
        super.addObserver(subscriber);
    }

    public void aboutGuppy () {
        logger.info("name : {}", this.name);
        logger.info("company : {}", this.company);
        logger.info("status : {}", this.status);
        logger.info("age : {}", this.age);
    }

}

// 소식을 구독하는 구독자에 해당합니다.
public class JohnSubscriber implements Observer {

    private static final Logger logger = LoggerFactory.getLogger(JohnSubscriber.class);

    // 소식(이벤트)이 발행되면 이에 따른 비지니스 로직을 수행합니다.
    @Override
    public void update(Observable o, Object info) {
        logger.info("oh..? - {}", info);

        if (info instanceof String) {
            boolean isEnd = this.parsingInfoForEndSignal((String) info);

            if (isEnd) {
                logger.info("Wow!");
            }
        }


        if (o instanceof GuppyPublisher) {
            ((GuppyPublisher) o).aboutGuppy();
        }

        logger.info("=========== 9분선 =============");
    }

    private boolean parsingInfoForEndSignal (String info) {
        String regex = "^(\\[([a-zA-Z|\\s]*)(\\/[a-zA-Z]*)?\\])?(.*)$";

        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(info);

        if (matcher.find()) {
            String endSignal = matcher.group(2); // 두번째 괄호

            if ("END".equals(endSignal)) {
                return true;
            }
        }

        return false;
    }
}

public class StackSubscriber implements Subscriber {

    private static final Logger logger = LoggerFactory.getLogger(StackSubscriber.class);
    private Subscription subscription;

    @Override
    public void onSubscribe(Subscription subscription) {
        this.subscription = subscription;

        subscription.request(1);
    }

    @Override
    public void onNext(Object o) {
        logger.info("onNext - {}", o);

        subscription.request(10);
    }

    @Override
    public void onError(Throwable throwable) {
        logger.error("onError - {}", throwable.getMessage());
    }

    @Override
    public void onComplete() {
        logger.info("COMPLETE");
    }

}

public class StackPublisher implements Publisher {

    private static final Logger logger = LoggerFactory.getLogger(StackPublisher.class);

    private Stack<Integer> stack;

    public StackPublisher() {
        this.stack = new Stack<>();

    }

    @Override
    public void subscribe(Subscriber subscriber) {
        initStack();

        subscriber.onSubscribe(new Subscription() {
            public void request(long l) {

                logger.info("Request : {}", l);

                if(l < 0) {
                    notifyException();
                    return;
                }

                for(int i = 1 ; i <= l ; i++) {
                    if(stack.empty()) {
                        notifyComplete();

                        return;
                    }

                    notifyNextEvent();
                }
            }

            private void notifyNextEvent() {
                subscriber.onNext(stack.pop());
            }

            private void notifyComplete() {
                subscriber.onComplete();
            }

            private void notifyException() {
                subscriber.onError(new Exception("  0 이상의 숫자를 넣어야 합니다"));
            }

            public void cancel() {

            }
        });
    }

    private void initStack() {
        for(int i = 0; i < 10 ; i++){
            stack.push(i);
        }
    }
}