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.*;
import java.util.concurrent.atomic.*;

import org.reactivestreams.*;

import io.reactivex.*;
import io.reactivex.internal.disposables.SequentialDisposable;
import io.reactivex.internal.subscriptions.*;
import io.reactivex.plugins.RxJavaPlugins;

import static io.reactivex.internal.util.ExceptionHelper.timeoutMessage;

public final class FlowableTimeoutTimed<T> extends AbstractFlowableWithUpstream<T, T> {
    final long timeout;
    final TimeUnit unit;
    final Scheduler scheduler;
    final Publisher<? extends T> other;

    public FlowableTimeoutTimed(Flowable<T> source,
            long timeout, TimeUnit unit, Scheduler scheduler, Publisher<? extends T> other) {
        super(source);
        this.timeout = timeout;
        this.unit = unit;
        this.scheduler = scheduler;
        this.other = other;
    }

    @Override
    protected void subscribeActual(Subscriber<? super T> s) {
        if (other == null) {
            TimeoutSubscriber<T> parent = new TimeoutSubscriber<T>(s, timeout, unit, scheduler.createWorker());
            s.onSubscribe(parent);
            parent.startTimeout(0L);
            source.subscribe(parent);
        } else {
            TimeoutFallbackSubscriber<T> parent = new TimeoutFallbackSubscriber<T>(s, timeout, unit, scheduler.createWorker(), other);
            s.onSubscribe(parent);
            parent.startTimeout(0L);
            source.subscribe(parent);
        }
    }

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

        private static final long serialVersionUID = 3764492702657003550L;

        final Subscriber<? super T> downstream;

        final long timeout;

        final TimeUnit unit;

        final Scheduler.Worker worker;

        final SequentialDisposable task;

        final AtomicReference<Subscription> upstream;

        final AtomicLong requested;

        TimeoutSubscriber(Subscriber<? super T> actual, long timeout, TimeUnit unit, Scheduler.Worker worker) {
            this.downstream = actual;
            this.timeout = timeout;
            this.unit = unit;
            this.worker = worker;
            this.task = new SequentialDisposable();
            this.upstream = new AtomicReference<Subscription>();
            this.requested = new AtomicLong();
        }

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

        @Override
        public void onNext(T t) {
            long idx = get();
            if (idx == Long.MAX_VALUE || !compareAndSet(idx, idx + 1)) {
                return;
            }

            task.get().dispose();

            downstream.onNext(t);

            startTimeout(idx + 1);
        }

        void startTimeout(long nextIndex) {
            task.replace(worker.schedule(new TimeoutTask(nextIndex, this), timeout, unit));
        }

        @Override
        public void onError(Throwable t) {
            if (getAndSet(Long.MAX_VALUE) != Long.MAX_VALUE) {
                task.dispose();

                downstream.onError(t);

                worker.dispose();
            } else {
                RxJavaPlugins.onError(t);
            }
        }

        @Override
        public void onComplete() {
            if (getAndSet(Long.MAX_VALUE) != Long.MAX_VALUE) {
                task.dispose();

                downstream.onComplete();

                worker.dispose();
            }
        }

        @Override
        public void onTimeout(long idx) {
            if (compareAndSet(idx, Long.MAX_VALUE)) {
                SubscriptionHelper.cancel(upstream);

                downstream.onError(new TimeoutException(timeoutMessage(timeout, unit)));

                worker.dispose();
            }
        }

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

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

    static final class TimeoutTask implements Runnable {

        final TimeoutSupport parent;

        final long idx;

        TimeoutTask(long idx, TimeoutSupport parent) {
            this.idx = idx;
            this.parent = parent;
        }

        @Override
        public void run() {
            parent.onTimeout(idx);
        }
    }

    static final class TimeoutFallbackSubscriber<T> extends SubscriptionArbiter
    implements FlowableSubscriber<T>, TimeoutSupport {

        private static final long serialVersionUID = 3764492702657003550L;

        final Subscriber<? super T> downstream;

        final long timeout;

        final TimeUnit unit;

        final Scheduler.Worker worker;

        final SequentialDisposable task;

        final AtomicReference<Subscription> upstream;

        final AtomicLong index;

        long consumed;

        Publisher<? extends T> fallback;

        TimeoutFallbackSubscriber(Subscriber<? super T> actual, long timeout, TimeUnit unit,
                Scheduler.Worker worker, Publisher<? extends T> fallback) {
            super(true);
            this.downstream = actual;
            this.timeout = timeout;
            this.unit = unit;
            this.worker = worker;
            this.fallback = fallback;
            this.task = new SequentialDisposable();
            this.upstream = new AtomicReference<Subscription>();
            this.index = new AtomicLong();
        }

        @Override
        public void onSubscribe(Subscription s) {
            if (SubscriptionHelper.setOnce(upstream, s)) {
                setSubscription(s);
            }
        }

        @Override
        public void onNext(T t) {
            long idx = index.get();
            if (idx == Long.MAX_VALUE || !index.compareAndSet(idx, idx + 1)) {
                return;
            }

            task.get().dispose();

            consumed++;

            downstream.onNext(t);

            startTimeout(idx + 1);
        }

        void startTimeout(long nextIndex) {
            task.replace(worker.schedule(new TimeoutTask(nextIndex, this), timeout, unit));
        }

        @Override
        public void onError(Throwable t) {
            if (index.getAndSet(Long.MAX_VALUE) != Long.MAX_VALUE) {
                task.dispose();

                downstream.onError(t);

                worker.dispose();
            } else {
                RxJavaPlugins.onError(t);
            }
        }

        @Override
        public void onComplete() {
            if (index.getAndSet(Long.MAX_VALUE) != Long.MAX_VALUE) {
                task.dispose();

                downstream.onComplete();

                worker.dispose();
            }
        }

        @Override
        public void onTimeout(long idx) {
            if (index.compareAndSet(idx, Long.MAX_VALUE)) {
                SubscriptionHelper.cancel(upstream);

                long c = consumed;
                if (c != 0L) {
                    produced(c);
                }

                Publisher<? extends T> f = fallback;
                fallback = null;

                f.subscribe(new FallbackSubscriber<T>(downstream, this));

                worker.dispose();
            }
        }

        @Override
        public void cancel() {
            super.cancel();
            worker.dispose();
        }
    }

    static final class FallbackSubscriber<T> implements FlowableSubscriber<T> {

        final Subscriber<? super T> downstream;

        final SubscriptionArbiter arbiter;

        FallbackSubscriber(Subscriber<? super T> actual, SubscriptionArbiter arbiter) {
            this.downstream = actual;
            this.arbiter = arbiter;
        }

        @Override
        public void onSubscribe(Subscription s) {
            arbiter.setSubscription(s);
        }

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

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

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

    interface TimeoutSupport {

        void onTimeout(long idx);

    }
}