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 java.util.concurrent.Callable;

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 ObservableMapNotification<T, R> extends AbstractObservableWithUpstream<T, ObservableSource<? extends R>> {

    final Function<? super T, ? extends ObservableSource<? extends R>> onNextMapper;
    final Function<? super Throwable, ? extends ObservableSource<? extends R>> onErrorMapper;
    final Callable<? extends ObservableSource<? extends R>> onCompleteSupplier;

    public ObservableMapNotification(
            ObservableSource<T> source,
            Function<? super T, ? extends ObservableSource<? extends R>> onNextMapper,
            Function<? super Throwable, ? extends ObservableSource<? extends R>> onErrorMapper,
                    Callable<? extends ObservableSource<? extends R>> onCompleteSupplier) {
        super(source);
        this.onNextMapper = onNextMapper;
        this.onErrorMapper = onErrorMapper;
        this.onCompleteSupplier = onCompleteSupplier;
    }

    @Override
    public void subscribeActual(Observer<? super ObservableSource<? extends R>> t) {
        source.subscribe(new MapNotificationObserver<T, R>(t, onNextMapper, onErrorMapper, onCompleteSupplier));
    }

    static final class MapNotificationObserver<T, R>
    implements Observer<T>, Disposable {
        final Observer<? super ObservableSource<? extends R>> downstream;
        final Function<? super T, ? extends ObservableSource<? extends R>> onNextMapper;
        final Function<? super Throwable, ? extends ObservableSource<? extends R>> onErrorMapper;
        final Callable<? extends ObservableSource<? extends R>> onCompleteSupplier;

        Disposable upstream;

        MapNotificationObserver(Observer<? super ObservableSource<? extends R>> actual,
                Function<? super T, ? extends ObservableSource<? extends R>> onNextMapper,
                Function<? super Throwable, ? extends ObservableSource<? extends R>> onErrorMapper,
                        Callable<? extends ObservableSource<? extends R>> onCompleteSupplier) {
            this.downstream = actual;
            this.onNextMapper = onNextMapper;
            this.onErrorMapper = onErrorMapper;
            this.onCompleteSupplier = onCompleteSupplier;
        }

        @Override
        public void onSubscribe(Disposable d) {
            if (DisposableHelper.validate(this.upstream, d)) {
                this.upstream = d;
                downstream.onSubscribe(this);
            }
        }

        @Override
        public void dispose() {
            upstream.dispose();
        }

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

        @Override
        public void onNext(T t) {
            ObservableSource<? extends R> p;

            try {
                p = ObjectHelper.requireNonNull(onNextMapper.apply(t), "The onNext ObservableSource returned is null");
            } catch (Throwable e) {
                Exceptions.throwIfFatal(e);
                downstream.onError(e);
                return;
            }

            downstream.onNext(p);
        }

        @Override
        public void onError(Throwable t) {
            ObservableSource<? extends R> p;

            try {
                p = ObjectHelper.requireNonNull(onErrorMapper.apply(t), "The onError ObservableSource returned is null");
            } catch (Throwable e) {
                Exceptions.throwIfFatal(e);
                downstream.onError(new CompositeException(t, e));
                return;
            }

            downstream.onNext(p);
            downstream.onComplete();
        }

        @Override
        public void onComplete() {
            ObservableSource<? extends R> p;

            try {
                p = ObjectHelper.requireNonNull(onCompleteSupplier.call(), "The onComplete ObservableSource returned is null");
            } catch (Throwable e) {
                Exceptions.throwIfFatal(e);
                downstream.onError(e);
                return;
            }

            downstream.onNext(p);
            downstream.onComplete();
        }
    }
}