Copyright (c) 2016-present, RxJava Contributors.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is
distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
the License for the specific language governing permissions and limitations under the License.
/**
 * Copyright (c) 2016-present, RxJava Contributors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
 * the License for the specific language governing permissions and limitations under the License.
 */
package io.reactivex.internal.operators.flowable;

import java.util.concurrent.atomic.*;

import org.reactivestreams.*;

import io.reactivex.*;
import io.reactivex.internal.subscriptions.SubscriptionHelper;
import io.reactivex.plugins.RxJavaPlugins;

Delays the subscription to the main source until the other
observable fires an event or completes.
Type parameters:
<T> – the main type
<U> – the other value type, ignored/**
 * Delays the subscription to the main source until the other
 * observable fires an event or completes.
 * @param <T> the main type
 * @param <U> the other value type, ignored
 */
public final class FlowableDelaySubscriptionOther<T, U> extends Flowable<T> {
    final Publisher<? extends T> main;
    final Publisher<U> other;

    public FlowableDelaySubscriptionOther(Publisher<? extends T> main, Publisher<U> other) {
        this.main = main;
        this.other = other;
    }

    @Override
    public void subscribeActual(final Subscriber<? super T> child) {
        MainSubscriber<T> parent = new MainSubscriber<T>(child, main);
        child.onSubscribe(parent);
        other.subscribe(parent.other);
    }

    static final class MainSubscriber<T> extends AtomicLong implements FlowableSubscriber<T>, Subscription {

        private static final long serialVersionUID = 2259811067697317255L;

        final Subscriber<? super T> downstream;

        final Publisher<? extends T> main;

        final OtherSubscriber other;

        final AtomicReference<Subscription> upstream;

        MainSubscriber(Subscriber<? super T> downstream, Publisher<? extends T> main) {
            this.downstream = downstream;
            this.main = main;
            this.other = new OtherSubscriber();
            this.upstream = new AtomicReference<Subscription>();
        }

        void next() {
            main.subscribe(this);
        }

        @Override
        public void onNext(T t) {
            downstream.onNext(t);
        }

        @Override
        public void onError(Throwable t) {
            downstream.onError(t);
        }

        @Override
        public void onComplete() {
            downstream.onComplete();
        }

        @Override
        public void request(long n) {
            if (SubscriptionHelper.validate(n)) {
                SubscriptionHelper.deferredRequest(upstream, this, n);
            }
        }

        @Override
        public void cancel() {
            SubscriptionHelper.cancel(other);
            SubscriptionHelper.cancel(upstream);
        }

        @Override
        public void onSubscribe(Subscription s) {
            SubscriptionHelper.deferredSetOnce(upstream, this, s);
        }

        final class OtherSubscriber extends AtomicReference<Subscription> implements FlowableSubscriber<Object> {

            private static final long serialVersionUID = -3892798459447644106L;

            @Override
            public void onSubscribe(Subscription s) {
                if (SubscriptionHelper.setOnce(this, s)) {
                    s.request(Long.MAX_VALUE);
                }
            }

            @Override
            public void onNext(Object t) {
                Subscription s = get();
                if (s != SubscriptionHelper.CANCELLED) {
                    lazySet(SubscriptionHelper.CANCELLED);
                    s.cancel();
                    next();
                }
            }

            @Override
            public void onError(Throwable t) {
                Subscription s = get();
                if (s != SubscriptionHelper.CANCELLED) {
                    downstream.onError(t);
                } else {
                    RxJavaPlugins.onError(t);
                }
            }

            @Override
            public void onComplete() {
                Subscription s = get();
                if (s != SubscriptionHelper.CANCELLED) {
                    next();
                }
            }
        }
}
}