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.TimeUnit;

import io.reactivex.*;
import io.reactivex.Scheduler.Worker;
import io.reactivex.disposables.Disposable;
import io.reactivex.internal.disposables.DisposableHelper;
import io.reactivex.observers.SerializedObserver;

public final class ObservableDelay<T> extends AbstractObservableWithUpstream<T, T> {
    final long delay;
    final TimeUnit unit;
    final Scheduler scheduler;
    final boolean delayError;

    public ObservableDelay(ObservableSource<T> source, long delay, TimeUnit unit, Scheduler scheduler, boolean delayError) {
        super(source);
        this.delay = delay;
        this.unit = unit;
        this.scheduler = scheduler;
        this.delayError = delayError;
    }

    @Override
    @SuppressWarnings("unchecked")
    public void subscribeActual(Observer<? super T> t) {
        Observer<T> observer;
        if (delayError) {
            observer = (Observer<T>)t;
        } else {
            observer = new SerializedObserver<T>(t);
        }

        Scheduler.Worker w = scheduler.createWorker();

        source.subscribe(new DelayObserver<T>(observer, delay, unit, w, delayError));
    }

    static final class DelayObserver<T> implements Observer<T>, Disposable {
        final Observer<? super T> downstream;
        final long delay;
        final TimeUnit unit;
        final Scheduler.Worker w;
        final boolean delayError;

        Disposable upstream;

        DelayObserver(Observer<? super T> actual, long delay, TimeUnit unit, Worker w, boolean delayError) {
            super();
            this.downstream = actual;
            this.delay = delay;
            this.unit = unit;
            this.w = w;
            this.delayError = delayError;
        }

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

        @Override
        public void onNext(final T t) {
            w.schedule(new OnNext(t), delay, unit);
        }

        @Override
        public void onError(final Throwable t) {
            w.schedule(new OnError(t), delayError ? delay : 0, unit);
        }

        @Override
        public void onComplete() {
            w.schedule(new OnComplete(), delay, unit);
        }

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

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

        final class OnNext implements Runnable {
            private final T t;

            OnNext(T t) {
                this.t = t;
            }

            @Override
            public void run() {
                downstream.onNext(t);
            }
        }

        final class OnError implements Runnable {
            private final Throwable throwable;

            OnError(Throwable throwable) {
                this.throwable = throwable;
            }

            @Override
            public void run() {
                try {
                    downstream.onError(throwable);
                } finally {
                    w.dispose();
                }
            }
        }

        final class OnComplete implements Runnable {
            @Override
            public void run() {
                try {
                    downstream.onComplete();
                } finally {
                    w.dispose();
                }
            }
        }
    }
}