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.AtomicInteger;

import io.reactivex.*;
import io.reactivex.disposables.*;
import io.reactivex.internal.util.AtomicThrowable;
import io.reactivex.plugins.RxJavaPlugins;

public final class CompletableMergeDelayErrorArray extends Completable {

    final CompletableSource[] sources;

    public CompletableMergeDelayErrorArray(CompletableSource[] sources) {
        this.sources = sources;
    }

    @Override
    public void subscribeActual(final CompletableObserver observer) {
        final CompositeDisposable set = new CompositeDisposable();
        final AtomicInteger wip = new AtomicInteger(sources.length + 1);

        final AtomicThrowable error = new AtomicThrowable();

        observer.onSubscribe(set);

        for (CompletableSource c : sources) {
            if (set.isDisposed()) {
                return;
            }

            if (c == null) {
                Throwable ex = new NullPointerException("A completable source is null");
                error.addThrowable(ex);
                wip.decrementAndGet();
                continue;
            }

            c.subscribe(new MergeInnerCompletableObserver(observer, set, error, wip));
        }

        if (wip.decrementAndGet() == 0) {
            Throwable ex = error.terminate();
            if (ex == null) {
                observer.onComplete();
            } else {
                observer.onError(ex);
            }
        }
    }

    static final class MergeInnerCompletableObserver
    implements CompletableObserver {
        final CompletableObserver downstream;
        final CompositeDisposable set;
        final AtomicThrowable error;
        final AtomicInteger wip;

        MergeInnerCompletableObserver(CompletableObserver observer, CompositeDisposable set, AtomicThrowable error,
                AtomicInteger wip) {
            this.downstream = observer;
            this.set = set;
            this.error = error;
            this.wip = wip;
        }

        @Override
        public void onSubscribe(Disposable d) {
            set.add(d);
        }

        @Override
        public void onError(Throwable e) {
            if (error.addThrowable(e)) {
                tryTerminate();
            } else {
                RxJavaPlugins.onError(e);
            }
        }

        @Override
        public void onComplete() {
            tryTerminate();
        }

        void tryTerminate() {
            if (wip.decrementAndGet() == 0) {
                Throwable ex = error.terminate();
                if (ex == null) {
                    downstream.onComplete();
                } else {
                    downstream.onError(ex);
                }
            }
        }
    }
}