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 org.reactivestreams.*;

import io.reactivex.*;
import io.reactivex.exceptions.Exceptions;
import io.reactivex.functions.*;
import io.reactivex.internal.subscriptions.*;
import io.reactivex.plugins.RxJavaPlugins;

public final class FlowableDoOnLifecycle<T> extends AbstractFlowableWithUpstream<T, T> {
    private final Consumer<? super Subscription> onSubscribe;
    private final LongConsumer onRequest;
    private final Action onCancel;

    public FlowableDoOnLifecycle(Flowable<T> source, Consumer<? super Subscription> onSubscribe,
            LongConsumer onRequest, Action onCancel) {
        super(source);
        this.onSubscribe = onSubscribe;
        this.onRequest = onRequest;
        this.onCancel = onCancel;
    }

    @Override
    protected void subscribeActual(Subscriber<? super T> s) {
        source.subscribe(new SubscriptionLambdaSubscriber<T>(s, onSubscribe, onRequest, onCancel));
    }

    static final class SubscriptionLambdaSubscriber<T> implements FlowableSubscriber<T>, Subscription {
        final Subscriber<? super T> downstream;
        final Consumer<? super Subscription> onSubscribe;
        final LongConsumer onRequest;
        final Action onCancel;

        Subscription upstream;

        SubscriptionLambdaSubscriber(Subscriber<? super T> actual,
                Consumer<? super Subscription> onSubscribe,
                LongConsumer onRequest,
                Action onCancel) {
            this.downstream = actual;
            this.onSubscribe = onSubscribe;
            this.onCancel = onCancel;
            this.onRequest = onRequest;
        }

        @Override
        public void onSubscribe(Subscription s) {
            // this way, multiple calls to onSubscribe can show up in tests that use doOnSubscribe to validate behavior
            try {
                onSubscribe.accept(s);
            } catch (Throwable e) {
                Exceptions.throwIfFatal(e);
                s.cancel();
                this.upstream = SubscriptionHelper.CANCELLED;
                EmptySubscription.error(e, downstream);
                return;
            }
            if (SubscriptionHelper.validate(this.upstream, s)) {
                this.upstream = s;
                downstream.onSubscribe(this);
            }
        }

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

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

        @Override
        public void onComplete() {
            if (upstream != SubscriptionHelper.CANCELLED) {
                downstream.onComplete();
            }
        }

        @Override
        public void request(long n) {
            try {
                onRequest.accept(n);
            } catch (Throwable e) {
                Exceptions.throwIfFatal(e);
                RxJavaPlugins.onError(e);
            }
            upstream.request(n);
        }

        @Override
        public void cancel() {
            Subscription s = upstream;
            if (s != SubscriptionHelper.CANCELLED) {
                upstream = SubscriptionHelper.CANCELLED;
                try {
                    onCancel.run();
                } catch (Throwable e) {
                    Exceptions.throwIfFatal(e);
                    RxJavaPlugins.onError(e);
                }
                s.cancel();
            }
        }
    }
}