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.completable;

import java.util.concurrent.atomic.AtomicReference;

import io.reactivex.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.internal.disposables.DisposableHelper;

public final class CompletableAndThenCompletable extends Completable {

    final CompletableSource source;

    final CompletableSource next;

    public CompletableAndThenCompletable(CompletableSource source, CompletableSource next) {
        this.source = source;
        this.next = next;
    }

    @Override
    protected void subscribeActual(CompletableObserver observer) {
        source.subscribe(new SourceObserver(observer, next));
    }

    static final class SourceObserver
            extends AtomicReference<Disposable>
            implements CompletableObserver, Disposable {

        private static final long serialVersionUID = -4101678820158072998L;

        final CompletableObserver actualObserver;

        final CompletableSource next;

        SourceObserver(CompletableObserver actualObserver, CompletableSource next) {
            this.actualObserver = actualObserver;
            this.next = next;
        }

        @Override
        public void onSubscribe(Disposable d) {
            if (DisposableHelper.setOnce(this, d)) {
                actualObserver.onSubscribe(this);
            }
        }

        @Override
        public void onError(Throwable e) {
            actualObserver.onError(e);
        }

        @Override
        public void onComplete() {
            next.subscribe(new NextObserver(this, actualObserver));
        }

        @Override
        public void dispose() {
            DisposableHelper.dispose(this);
        }

        @Override
        public boolean isDisposed() {
            return DisposableHelper.isDisposed(get());
        }
    }

    static final class NextObserver implements CompletableObserver {

        final AtomicReference<Disposable> parent;

        final CompletableObserver downstream;

        public NextObserver(AtomicReference<Disposable> parent, CompletableObserver downstream) {
            this.parent = parent;
            this.downstream = downstream;
        }

        @Override
        public void onSubscribe(Disposable d) {
            DisposableHelper.replace(parent, d);
        }

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

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