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.exceptions.*;
import io.reactivex.functions.Function;
import io.reactivex.internal.disposables.DisposableHelper;
import io.reactivex.internal.functions.ObjectHelper;

public final class CompletableResumeNext extends Completable {

    final CompletableSource source;

    final Function<? super Throwable, ? extends CompletableSource> errorMapper;

    public CompletableResumeNext(CompletableSource source,
            Function<? super Throwable, ? extends CompletableSource> errorMapper) {
        this.source = source;
        this.errorMapper = errorMapper;
    }

    @Override
    protected void subscribeActual(final CompletableObserver observer) {
        ResumeNextObserver parent = new ResumeNextObserver(observer, errorMapper);
        observer.onSubscribe(parent);
        source.subscribe(parent);
    }

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

        private static final long serialVersionUID = 5018523762564524046L;

        final CompletableObserver downstream;

        final Function<? super Throwable, ? extends CompletableSource> errorMapper;

        boolean once;

        ResumeNextObserver(CompletableObserver observer, Function<? super Throwable, ? extends CompletableSource> errorMapper) {
            this.downstream = observer;
            this.errorMapper = errorMapper;
        }

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

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

        @Override
        public void onError(Throwable e) {
            if (once) {
                downstream.onError(e);
                return;
            }
            once = true;

            CompletableSource c;

            try {
                c = ObjectHelper.requireNonNull(errorMapper.apply(e), "The errorMapper returned a null CompletableSource");
            } catch (Throwable ex) {
                Exceptions.throwIfFatal(ex);
                downstream.onError(new CompositeException(e, ex));
                return;
            }

            c.subscribe(this);
        }

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

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