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.observable;

import io.reactivex.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.exceptions.*;
import io.reactivex.functions.Function;
import io.reactivex.internal.disposables.SequentialDisposable;
import io.reactivex.plugins.RxJavaPlugins;

public final class ObservableOnErrorNext<T> extends AbstractObservableWithUpstream<T, T> {
    final Function<? super Throwable, ? extends ObservableSource<? extends T>> nextSupplier;
    final boolean allowFatal;

    public ObservableOnErrorNext(ObservableSource<T> source,
                                 Function<? super Throwable, ? extends ObservableSource<? extends T>> nextSupplier, boolean allowFatal) {
        super(source);
        this.nextSupplier = nextSupplier;
        this.allowFatal = allowFatal;
    }

    @Override
    public void subscribeActual(Observer<? super T> t) {
        OnErrorNextObserver<T> parent = new OnErrorNextObserver<T>(t, nextSupplier, allowFatal);
        t.onSubscribe(parent.arbiter);
        source.subscribe(parent);
    }

    static final class OnErrorNextObserver<T> implements Observer<T> {
        final Observer<? super T> downstream;
        final Function<? super Throwable, ? extends ObservableSource<? extends T>> nextSupplier;
        final boolean allowFatal;
        final SequentialDisposable arbiter;

        boolean once;

        boolean done;

        OnErrorNextObserver(Observer<? super T> actual, Function<? super Throwable, ? extends ObservableSource<? extends T>> nextSupplier, boolean allowFatal) {
            this.downstream = actual;
            this.nextSupplier = nextSupplier;
            this.allowFatal = allowFatal;
            this.arbiter = new SequentialDisposable();
        }

        @Override
        public void onSubscribe(Disposable d) {
            arbiter.replace(d);
        }

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

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

            if (allowFatal && !(t instanceof Exception)) {
                downstream.onError(t);
                return;
            }

            ObservableSource<? extends T> p;

            try {
                p = nextSupplier.apply(t);
            } catch (Throwable e) {
                Exceptions.throwIfFatal(e);
                downstream.onError(new CompositeException(t, e));
                return;
            }

            if (p == null) {
                NullPointerException npe = new NullPointerException("Observable is null");
                npe.initCause(t);
                downstream.onError(npe);
                return;
            }

            p.subscribe(this);
        }

        @Override
        public void onComplete() {
            if (done) {
                return;
            }
            done = true;
            once = true;
            downstream.onComplete();
        }
    }
}