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.maybe;

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

Peeks into the lifecycle of a Maybe and MaybeObserver.
Type parameters:
<T> – the value type/**
 * Peeks into the lifecycle of a Maybe and MaybeObserver.
 *
 * @param <T> the value type
 */
public final class MaybePeek<T> extends AbstractMaybeWithUpstream<T, T> {

    final Consumer<? super Disposable> onSubscribeCall;

    final Consumer<? super T> onSuccessCall;

    final Consumer<? super Throwable> onErrorCall;

    final Action onCompleteCall;

    final Action onAfterTerminate;

    final Action onDisposeCall;

    public MaybePeek(MaybeSource<T> source, Consumer<? super Disposable> onSubscribeCall,
            Consumer<? super T> onSuccessCall, Consumer<? super Throwable> onErrorCall, Action onCompleteCall,
            Action onAfterTerminate, Action onDispose) {
        super(source);
        this.onSubscribeCall = onSubscribeCall;
        this.onSuccessCall = onSuccessCall;
        this.onErrorCall = onErrorCall;
        this.onCompleteCall = onCompleteCall;
        this.onAfterTerminate = onAfterTerminate;
        this.onDisposeCall = onDispose;
    }

    @Override
    protected void subscribeActual(MaybeObserver<? super T> observer) {
        source.subscribe(new MaybePeekObserver<T>(observer, this));
    }

    static final class MaybePeekObserver<T> implements MaybeObserver<T>, Disposable {
        final MaybeObserver<? super T> downstream;

        final MaybePeek<T> parent;

        Disposable upstream;

        MaybePeekObserver(MaybeObserver<? super T> actual, MaybePeek<T> parent) {
            this.downstream = actual;
            this.parent = parent;
        }

        @Override
        public void dispose() {
            try {
                parent.onDisposeCall.run();
            } catch (Throwable ex) {
                Exceptions.throwIfFatal(ex);
                RxJavaPlugins.onError(ex);
            }

            upstream.dispose();
            upstream = DisposableHelper.DISPOSED;
        }

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

        @Override
        public void onSubscribe(Disposable d) {
            if (DisposableHelper.validate(this.upstream, d)) {
                try {
                    parent.onSubscribeCall.accept(d);
                } catch (Throwable ex) {
                    Exceptions.throwIfFatal(ex);
                    d.dispose();
                    this.upstream = DisposableHelper.DISPOSED;
                    EmptyDisposable.error(ex, downstream);
                    return;
                }

                this.upstream = d;

                downstream.onSubscribe(this);
            }
        }

        @Override
        public void onSuccess(T value) {
            if (this.upstream == DisposableHelper.DISPOSED) {
                return;
            }
            try {
                parent.onSuccessCall.accept(value);
            } catch (Throwable ex) {
                Exceptions.throwIfFatal(ex);
                onErrorInner(ex);
                return;
            }
            this.upstream = DisposableHelper.DISPOSED;

            downstream.onSuccess(value);

            onAfterTerminate();
        }

        @Override
        public void onError(Throwable e) {
            if (this.upstream == DisposableHelper.DISPOSED) {
                RxJavaPlugins.onError(e);
                return;
            }

            onErrorInner(e);
        }

        void onErrorInner(Throwable e) {
            try {
                parent.onErrorCall.accept(e);
            } catch (Throwable ex) {
                Exceptions.throwIfFatal(ex);
                e = new CompositeException(e, ex);
            }

            this.upstream = DisposableHelper.DISPOSED;

            downstream.onError(e);

            onAfterTerminate();
        }

        @Override
        public void onComplete() {
            if (this.upstream == DisposableHelper.DISPOSED) {
                return;
            }

            try {
                parent.onCompleteCall.run();
            } catch (Throwable ex) {
                Exceptions.throwIfFatal(ex);
                onErrorInner(ex);
                return;
            }
            this.upstream = DisposableHelper.DISPOSED;

            downstream.onComplete();

            onAfterTerminate();
        }

        void onAfterTerminate() {
            try {
                parent.onAfterTerminate.run();
            } catch (Throwable ex) {
                Exceptions.throwIfFatal(ex);
                RxJavaPlugins.onError(ex);
            }
        }
    }
}