/*
 * 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.rxjava3.internal.operators.flowable;

import org.reactivestreams.Subscription;

import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.disposables.Disposable;
import io.reactivex.rxjava3.internal.fuseable.FuseToFlowable;
import io.reactivex.rxjava3.internal.subscriptions.SubscriptionHelper;
import io.reactivex.rxjava3.plugins.RxJavaPlugins;

public final class FlowableIgnoreElementsCompletable<T> extends Completable implements FuseToFlowable<T> {

    final Flowable<T> source;

    public FlowableIgnoreElementsCompletable(Flowable<T> source) {
        this.source = source;
    }

    @Override
    protected void subscribeActual(final CompletableObserver t) {
        source.subscribe(new IgnoreElementsSubscriber<>(t));
    }

    @Override
    public Flowable<T> fuseToFlowable() {
        return RxJavaPlugins.onAssembly(new FlowableIgnoreElements<>(source));
    }

    static final class IgnoreElementsSubscriber<T> implements FlowableSubscriber<T>, Disposable {
        final CompletableObserver downstream;

        Subscription upstream;

        IgnoreElementsSubscriber(CompletableObserver downstream) {
            this.downstream = downstream;
        }

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

        @Override
        public void onNext(T t) {
            // deliberately ignored
        }

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

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

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

        @Override
        public boolean isDisposed() {
            return upstream == SubscriptionHelper.CANCELLED;
        }
    }
}
