/*
 * 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.rxjava4.internal.operators.flowable;

import static org.junit.Assert.*;
import static org.mockito.ArgumentMatchers.*;
import static org.mockito.Mockito.*;

import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.util.concurrent.locks.LockSupport;

import org.junit.*;
import org.mockito.InOrder;
import static java.util.concurrent.Flow.*;

import io.reactivex.rxjava4.core.*;
import io.reactivex.rxjava4.exceptions.TestException;
import io.reactivex.rxjava4.functions.*;
import io.reactivex.rxjava4.internal.disposables.SequentialDisposable;
import io.reactivex.rxjava4.internal.functions.Functions;
import io.reactivex.rxjava4.processors.PublishProcessor;
import io.reactivex.rxjava4.schedulers.*;
import io.reactivex.rxjava4.subscribers.*;
import io.reactivex.rxjava4.testsupport.TestHelper;

public class FlowableDelayTest extends RxJavaTest {
    private Subscriber<Long> subscriber;
    private Subscriber<Long> subscriber2;

    private TestScheduler scheduler;

    @Before
    public void before() {
        subscriber = TestHelper.mockSubscriber();
        subscriber2 = TestHelper.mockSubscriber();

        scheduler = new TestScheduler();
    }

    @Test
    public void delay() {
        Flowable<Long> source = Flowable.interval(1L, TimeUnit.SECONDS, scheduler).take(3);
        Flowable<Long> delayed = source.delay(500L, TimeUnit.MILLISECONDS, scheduler);
        delayed.subscribe(subscriber);

        InOrder inOrder = inOrder(subscriber);
        scheduler.advanceTimeTo(1499L, TimeUnit.MILLISECONDS);
        verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(1500L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(0L);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(2400L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(2500L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(1L);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(3400L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(3500L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(2L);
        verify(subscriber, times(1)).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));
    }

    @Test
    public void longDelay() {
        Flowable<Long> source = Flowable.interval(1L, TimeUnit.SECONDS, scheduler).take(3);
        Flowable<Long> delayed = source.delay(5L, TimeUnit.SECONDS, scheduler);
        delayed.subscribe(subscriber);

        InOrder inOrder = inOrder(subscriber);

        scheduler.advanceTimeTo(5999L, TimeUnit.MILLISECONDS);
        verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(6000L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(0L);
        scheduler.advanceTimeTo(6999L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        scheduler.advanceTimeTo(7000L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(1L);
        scheduler.advanceTimeTo(7999L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        scheduler.advanceTimeTo(8000L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(2L);
        inOrder.verify(subscriber, times(1)).onComplete();
        inOrder.verify(subscriber, never()).onNext(anyLong());
        inOrder.verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));
    }

    @Test
    public void delayWithError() {
        Flowable<Long> source = Flowable.interval(1L, TimeUnit.SECONDS, scheduler)
        .map(new Function<Long, Long>() {
            @Override
            public Long apply(Long value) {
                if (value == 1L) {
                    throw new RuntimeException("error!");
                }
                return value;
            }
        });
        Flowable<Long> delayed = source.delay(1L, TimeUnit.SECONDS, scheduler);
        delayed.subscribe(subscriber);

        InOrder inOrder = inOrder(subscriber);

        scheduler.advanceTimeTo(1999L, TimeUnit.MILLISECONDS);
        verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(2000L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onError(any(Throwable.class));
        inOrder.verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();

        scheduler.advanceTimeTo(5000L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        inOrder.verify(subscriber, never()).onError(any(Throwable.class));
        verify(subscriber, never()).onComplete();
    }

    @Test
    public void delayWithMultipleSubscriptions() {
        Flowable<Long> source = Flowable.interval(1L, TimeUnit.SECONDS, scheduler).take(3);
        Flowable<Long> delayed = source.delay(500L, TimeUnit.MILLISECONDS, scheduler);
        delayed.subscribe(subscriber);
        delayed.subscribe(subscriber2);

        InOrder inOrder = inOrder(subscriber);
        InOrder inOrder2 = inOrder(subscriber2);

        scheduler.advanceTimeTo(1499L, TimeUnit.MILLISECONDS);
        verify(subscriber, never()).onNext(anyLong());
        verify(subscriber2, never()).onNext(anyLong());

        scheduler.advanceTimeTo(1500L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(0L);
        inOrder2.verify(subscriber2, times(1)).onNext(0L);

        scheduler.advanceTimeTo(2499L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        inOrder2.verify(subscriber2, never()).onNext(anyLong());

        scheduler.advanceTimeTo(2500L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(1L);
        inOrder2.verify(subscriber2, times(1)).onNext(1L);

        verify(subscriber, never()).onComplete();
        verify(subscriber2, never()).onComplete();

        scheduler.advanceTimeTo(3500L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(2L);
        inOrder2.verify(subscriber2, times(1)).onNext(2L);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        inOrder2.verify(subscriber2, never()).onNext(anyLong());
        inOrder.verify(subscriber, times(1)).onComplete();
        inOrder2.verify(subscriber2, times(1)).onComplete();

        verify(subscriber, never()).onError(any(Throwable.class));
        verify(subscriber2, never()).onError(any(Throwable.class));
    }

    @Test
    public void delaySubscription() {
        Flowable<Integer> result = Flowable.just(1, 2, 3).delaySubscription(100, TimeUnit.MILLISECONDS, scheduler);

        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        result.subscribe(subscriber);

        inOrder.verify(subscriber, never()).onNext(any());
        inOrder.verify(subscriber, never()).onComplete();

        scheduler.advanceTimeBy(100, TimeUnit.MILLISECONDS);

        inOrder.verify(subscriber, times(1)).onNext(1);
        inOrder.verify(subscriber, times(1)).onNext(2);
        inOrder.verify(subscriber, times(1)).onNext(3);
        inOrder.verify(subscriber, times(1)).onComplete();

        verify(subscriber, never()).onError(any(Throwable.class));
    }

    @Test
    public void delaySubscriptionCancelBeforeTime() {
        Flowable<Integer> result = Flowable.just(1, 2, 3).delaySubscription(100, TimeUnit.MILLISECONDS, scheduler);

        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        TestSubscriber<Object> ts = new TestSubscriber<>(subscriber);

        result.subscribe(ts);
        ts.cancel();
        scheduler.advanceTimeBy(100, TimeUnit.MILLISECONDS);

        verify(subscriber, never()).onNext(any());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));
    }

    @Test
    public void delayWithFlowableNormal1() {
        PublishProcessor<Integer> source = PublishProcessor.create();
        final List<PublishProcessor<Integer>> delays = new ArrayList<>();
        final int n = 10;
        for (int i = 0; i < n; i++) {
            PublishProcessor<Integer> delay = PublishProcessor.create();
            delays.add(delay);
        }

        Function<Integer, Flowable<Integer>> delayFunc = new Function<Integer, Flowable<Integer>>() {
            @Override
            public Flowable<Integer> apply(Integer t1) {
                return delays.get(t1);
            }
        };

        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        source.delay(delayFunc).subscribe(subscriber);

        for (int i = 0; i < n; i++) {
            source.onNext(i);
            delays.get(i).onNext(i);
            inOrder.verify(subscriber).onNext(i);
        }
        source.onComplete();

        inOrder.verify(subscriber).onComplete();
        inOrder.verifyNoMoreInteractions();

        verify(subscriber, never()).onError(any(Throwable.class));
    }

    @Test
    public void delayWithFlowableSingleSend1() {
        PublishProcessor<Integer> source = PublishProcessor.create();
        final PublishProcessor<Integer> delay = PublishProcessor.create();

        Function<Integer, Flowable<Integer>> delayFunc = new Function<Integer, Flowable<Integer>>() {

            @Override
            public Flowable<Integer> apply(Integer t1) {
                return delay;
            }
        };
        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        source.delay(delayFunc).subscribe(subscriber);

        source.onNext(1);
        delay.onNext(1);
        delay.onNext(2);

        inOrder.verify(subscriber).onNext(1);
        inOrder.verifyNoMoreInteractions();
        verify(subscriber, never()).onError(any(Throwable.class));
    }

    @Test
    public void delayWithFlowableSourceThrows() {
        PublishProcessor<Integer> source = PublishProcessor.create();
        final PublishProcessor<Integer> delay = PublishProcessor.create();

        Function<Integer, Flowable<Integer>> delayFunc = new Function<Integer, Flowable<Integer>>() {

            @Override
            public Flowable<Integer> apply(Integer t1) {
                return delay;
            }
        };
        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        source.delay(delayFunc).subscribe(subscriber);
        source.onNext(1);
        source.onError(new TestException());
        delay.onNext(1);

        inOrder.verify(subscriber).onError(any(TestException.class));
        inOrder.verifyNoMoreInteractions();
        verify(subscriber, never()).onNext(any());
        verify(subscriber, never()).onComplete();
    }

    @Test
    public void delayWithFlowableDelayFunctionThrows() {
        PublishProcessor<Integer> source = PublishProcessor.create();

        Function<Integer, Flowable<Integer>> delayFunc = new Function<Integer, Flowable<Integer>>() {

            @Override
            public Flowable<Integer> apply(Integer t1) {
                throw new TestException();
            }
        };
        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        source.delay(delayFunc).subscribe(subscriber);
        source.onNext(1);

        inOrder.verify(subscriber).onError(any(TestException.class));
        inOrder.verifyNoMoreInteractions();
        verify(subscriber, never()).onNext(any());
        verify(subscriber, never()).onComplete();
    }

    @Test
    public void delayWithFlowableDelayThrows() {
        PublishProcessor<Integer> source = PublishProcessor.create();
        final PublishProcessor<Integer> delay = PublishProcessor.create();

        Function<Integer, Flowable<Integer>> delayFunc = new Function<Integer, Flowable<Integer>>() {

            @Override
            public Flowable<Integer> apply(Integer t1) {
                return delay;
            }
        };
        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        source.delay(delayFunc).subscribe(subscriber);
        source.onNext(1);
        delay.onError(new TestException());

        inOrder.verify(subscriber).onError(any(TestException.class));
        inOrder.verifyNoMoreInteractions();
        verify(subscriber, never()).onNext(any());
        verify(subscriber, never()).onComplete();
    }

    @Test
    public void delayWithFlowableSubscriptionNormal() {
        PublishProcessor<Integer> source = PublishProcessor.create();
        final PublishProcessor<Integer> delay = PublishProcessor.create();
        Function<Integer, Flowable<Integer>> delayFunc = new Function<Integer, Flowable<Integer>>() {

            @Override
            public Flowable<Integer> apply(Integer t1) {
                return delay;
            }
        };

        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        source.delay(delay, delayFunc).subscribe(subscriber);

        source.onNext(1);
        delay.onNext(1);

        source.onNext(2);
        delay.onNext(2);

        inOrder.verify(subscriber).onNext(2);
        inOrder.verifyNoMoreInteractions();
        verify(subscriber, never()).onError(any(Throwable.class));
        verify(subscriber, never()).onComplete();
    }

    @Test
    public void delayWithFlowableSubscriptionFunctionThrows() {
        PublishProcessor<Integer> source = PublishProcessor.create();
        final PublishProcessor<Integer> delay = PublishProcessor.create();
        Supplier<Flowable<Integer>> subFunc = new Supplier<Flowable<Integer>>() {
            @Override
            public Flowable<Integer> get() {
                throw new TestException();
            }
        };
        Function<Integer, Flowable<Integer>> delayFunc = new Function<Integer, Flowable<Integer>>() {

            @Override
            public Flowable<Integer> apply(Integer t1) {
                return delay;
            }
        };

        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        source.delay(Flowable.defer(subFunc), delayFunc).subscribe(subscriber);

        source.onNext(1);
        delay.onNext(1);

        source.onNext(2);

        inOrder.verify(subscriber).onError(any(TestException.class));
        inOrder.verifyNoMoreInteractions();
        verify(subscriber, never()).onNext(any());
        verify(subscriber, never()).onComplete();
    }

    @Test
    public void delayWithFlowableSubscriptionThrows() {
        PublishProcessor<Integer> source = PublishProcessor.create();
        final PublishProcessor<Integer> delay = PublishProcessor.create();
        Supplier<Flowable<Integer>> subFunc = new Supplier<Flowable<Integer>>() {
            @Override
            public Flowable<Integer> get() {
                return delay;
            }
        };
        Function<Integer, Flowable<Integer>> delayFunc = new Function<Integer, Flowable<Integer>>() {

            @Override
            public Flowable<Integer> apply(Integer t1) {
                return delay;
            }
        };

        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        source.delay(Flowable.defer(subFunc), delayFunc).subscribe(subscriber);

        source.onNext(1);
        delay.onError(new TestException());

        source.onNext(2);

        inOrder.verify(subscriber).onError(any(TestException.class));
        inOrder.verifyNoMoreInteractions();
        verify(subscriber, never()).onNext(any());
        verify(subscriber, never()).onComplete();
    }

    @Test
    public void delayWithFlowableEmptyDelayer() {
        PublishProcessor<Integer> source = PublishProcessor.create();

        Function<Integer, Flowable<Integer>> delayFunc = new Function<Integer, Flowable<Integer>>() {

            @Override
            public Flowable<Integer> apply(Integer t1) {
                return Flowable.empty();
            }
        };
        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        source.delay(delayFunc).subscribe(subscriber);

        source.onNext(1);
        source.onComplete();

        inOrder.verify(subscriber).onNext(1);
        inOrder.verify(subscriber).onComplete();
        inOrder.verifyNoMoreInteractions();
        verify(subscriber, never()).onError(any(Throwable.class));
    }

    @Test
    public void delayWithFlowableSubscriptionRunCompletion() {
        PublishProcessor<Integer> source = PublishProcessor.create();
        final PublishProcessor<Integer> sdelay = PublishProcessor.create();
        final PublishProcessor<Integer> delay = PublishProcessor.create();
        Supplier<Flowable<Integer>> subFunc = new Supplier<Flowable<Integer>>() {
            @Override
            public Flowable<Integer> get() {
                return sdelay;
            }
        };
        Function<Integer, Flowable<Integer>> delayFunc = new Function<Integer, Flowable<Integer>>() {

            @Override
            public Flowable<Integer> apply(Integer t1) {
                return delay;
            }
        };

        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        source.delay(Flowable.defer(subFunc), delayFunc).subscribe(subscriber);

        source.onNext(1);
        sdelay.onComplete();

        source.onNext(2);
        delay.onNext(2);

        inOrder.verify(subscriber).onNext(2);
        inOrder.verifyNoMoreInteractions();
        verify(subscriber, never()).onError(any(Throwable.class));
        verify(subscriber, never()).onComplete();
    }

    @Test
    public void delayWithFlowableAsTimed() {
        Flowable<Long> source = Flowable.interval(1L, TimeUnit.SECONDS, scheduler).take(3);

        final Flowable<Long> delayer = Flowable.timer(500L, TimeUnit.MILLISECONDS, scheduler);

        Function<Long, Flowable<Long>> delayFunc = new Function<Long, Flowable<Long>>() {
            @Override
            public Flowable<Long> apply(Long t1) {
                return delayer;
            }
        };

        Flowable<Long> delayed = source.delay(delayFunc);
        delayed.subscribe(subscriber);

        InOrder inOrder = inOrder(subscriber);
        scheduler.advanceTimeTo(1499L, TimeUnit.MILLISECONDS);
        verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(1500L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(0L);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(2400L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(2500L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(1L);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(3400L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, never()).onNext(anyLong());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));

        scheduler.advanceTimeTo(3500L, TimeUnit.MILLISECONDS);
        inOrder.verify(subscriber, times(1)).onNext(2L);
        verify(subscriber, times(1)).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));
    }

    @Test
    public void delayWithFlowableReorder() {
        int n = 3;

        PublishProcessor<Integer> source = PublishProcessor.create();
        final List<PublishProcessor<Integer>> subjects = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            subjects.add(PublishProcessor.<Integer> create());
        }

        Flowable<Integer> result = source.delay(new Function<Integer, Flowable<Integer>>() {

            @Override
            public Flowable<Integer> apply(Integer t1) {
                return subjects.get(t1);
            }
        });

        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        InOrder inOrder = inOrder(subscriber);

        result.subscribe(subscriber);

        for (int i = 0; i < n; i++) {
            source.onNext(i);
        }
        source.onComplete();

        inOrder.verify(subscriber, never()).onNext(anyInt());
        inOrder.verify(subscriber, never()).onComplete();

        for (int i = n - 1; i >= 0; i--) {
            subjects.get(i).onComplete();
            inOrder.verify(subscriber).onNext(i);
        }

        inOrder.verify(subscriber).onComplete();

        verify(subscriber, never()).onError(any(Throwable.class));
    }

    @Test
    public void delayEmitsEverything() {
        Flowable<Integer> source = Flowable.range(1, 5);
        Flowable<Integer> delayed = source.delay(500L, TimeUnit.MILLISECONDS, scheduler);
        delayed = delayed.doOnEach(new Consumer<Notification<Integer>>() {

            @Override
            public void accept(Notification<Integer> t1) {
                System.out.println(t1);
            }

        });
        TestSubscriber<Integer> ts = new TestSubscriber<>();
        delayed.subscribe(ts);
        // all will be delivered after 500ms since range does not delay between them
        scheduler.advanceTimeBy(500L, TimeUnit.MILLISECONDS);
        ts.assertValues(1, 2, 3, 4, 5);
    }

    @Test
    public void backpressureWithTimedDelay() {
        TestSubscriber<Integer> ts = new TestSubscriber<>();
        Flowable.range(1, Flowable.bufferSize() * 2)
                .delay(100, TimeUnit.MILLISECONDS)
                .observeOn(Schedulers.computation())
                .map(new Function<Integer, Integer>() {

                    int c;

                    @Override
                    public Integer apply(Integer t) {
                        if (c++ <= 0) {
                            try {
                                Thread.sleep(500);
                            } catch (InterruptedException e) {
                            }
                        }
                        return t;
                    }

                }).subscribe(ts);

        ts.awaitDone(5, TimeUnit.SECONDS);
        ts.assertNoErrors();
        assertEquals(Flowable.bufferSize() * 2, ts.values().size());
    }

    @Test
    public void backpressureWithSubscriptionTimedDelay() {
        TestSubscriber<Integer> ts = new TestSubscriber<>();
        Flowable.range(1, Flowable.bufferSize() * 2)
                .delaySubscription(100, TimeUnit.MILLISECONDS)
                .delay(100, TimeUnit.MILLISECONDS)
                .observeOn(Schedulers.computation())
                .map(new Function<Integer, Integer>() {

                    int c;

                    @Override
                    public Integer apply(Integer t) {
                        if (c++ <= 0) {
                            try {
                                Thread.sleep(500);
                            } catch (InterruptedException e) {
                            }
                        }
                        return t;
                    }

                }).subscribe(ts);

        ts.awaitDone(5, TimeUnit.SECONDS);
        ts.assertNoErrors();
        assertEquals(Flowable.bufferSize() * 2, ts.values().size());
    }

    @Test
    public void backpressureWithSelectorDelay() {
        TestSubscriber<Integer> ts = new TestSubscriber<>();
        Flowable.range(1, Flowable.bufferSize() * 2)
                .delay(new Function<Integer, Flowable<Long>>() {

                    @Override
                    public Flowable<Long> apply(Integer i) {
                        return Flowable.timer(100, TimeUnit.MILLISECONDS);
                    }

                })
                .observeOn(Schedulers.computation())
                .map(new Function<Integer, Integer>() {

                    int c;

                    @Override
                    public Integer apply(Integer t) {
                        if (c++ <= 0) {
                            try {
                                Thread.sleep(500);
                            } catch (InterruptedException e) {
                            }
                        }
                        return t;
                    }

                }).subscribe(ts);

        ts.awaitDone(5, TimeUnit.SECONDS);
        ts.assertNoErrors();
        assertEquals(Flowable.bufferSize() * 2, ts.values().size());
    }

    @Test
    public void backpressureWithSelectorDelayAndSubscriptionDelay() {
        TestSubscriber<Integer> ts = new TestSubscriber<>();
        Flowable.range(1, Flowable.bufferSize() * 2)
                .delay(Flowable.defer(new Supplier<Flowable<Long>>() {

                    @Override
                    public Flowable<Long> get() {
                        return Flowable.timer(500, TimeUnit.MILLISECONDS);
                    }
                }), new Function<Integer, Flowable<Long>>() {

                    @Override
                    public Flowable<Long> apply(Integer i) {
                        return Flowable.timer(100, TimeUnit.MILLISECONDS);
                    }

                })
                .observeOn(Schedulers.computation())
                .map(new Function<Integer, Integer>() {

                    int c;

                    @Override
                    public Integer apply(Integer t) {
                        if (c++ <= 0) {
                            try {
                                Thread.sleep(500);
                            } catch (InterruptedException e) {
                            }
                        }
                        return t;
                    }

                }).subscribe(ts);

        ts.awaitDone(5, TimeUnit.SECONDS);
        ts.assertNoErrors();
        assertEquals(Flowable.bufferSize() * 2, ts.values().size());
    }

    @Test
    public void errorRunsBeforeOnNext() {
        TestScheduler test = new TestScheduler();

        PublishProcessor<Integer> pp = PublishProcessor.create();

        TestSubscriber<Integer> ts = new TestSubscriber<>();

        pp.delay(1, TimeUnit.SECONDS, test).subscribe(ts);

        pp.onNext(1);

        test.advanceTimeBy(500, TimeUnit.MILLISECONDS);

        pp.onError(new TestException());

        test.advanceTimeBy(1, TimeUnit.SECONDS);

        ts.assertNoValues();
        ts.assertError(TestException.class);
        ts.assertNotComplete();
    }

    @Test
    public void delaySupplierSimple() {
        final PublishProcessor<Integer> pp = PublishProcessor.create();

        Flowable<Integer> source = Flowable.range(1, 5);

        TestSubscriber<Integer> ts = new TestSubscriber<>();

        source.delaySubscription(Flowable.defer(new Supplier<Publisher<Integer>>() {
            @Override
            public Publisher<Integer> get() {
                return pp;
            }
        })).subscribe(ts);

        ts.assertNoValues();
        ts.assertNoErrors();
        ts.assertNotComplete();

        pp.onNext(1);

        ts.assertValues(1, 2, 3, 4, 5);
        ts.assertComplete();
        ts.assertNoErrors();
    }

    @Test
    public void delaySupplierCompletes() {
        final PublishProcessor<Integer> pp = PublishProcessor.create();

        Flowable<Integer> source = Flowable.range(1, 5);

        TestSubscriber<Integer> ts = new TestSubscriber<>();

        source.delaySubscription(Flowable.defer(new Supplier<Publisher<Integer>>() {
            @Override
            public Publisher<Integer> get() {
                return pp;
            }
        })).subscribe(ts);

        ts.assertNoValues();
        ts.assertNoErrors();
        ts.assertNotComplete();

        // FIXME should this complete the source instead of consuming it?
        pp.onComplete();

        ts.assertValues(1, 2, 3, 4, 5);
        ts.assertComplete();
        ts.assertNoErrors();
    }

    @Test
    public void delaySupplierErrors() {
        final PublishProcessor<Integer> pp = PublishProcessor.create();

        Flowable<Integer> source = Flowable.range(1, 5);

        TestSubscriber<Integer> ts = new TestSubscriber<>();

        source.delaySubscription(Flowable.defer(new Supplier<Publisher<Integer>>() {
            @Override
            public Publisher<Integer> get() {
                return pp;
            }
        })).subscribe(ts);

        ts.assertNoValues();
        ts.assertNoErrors();
        ts.assertNotComplete();

        pp.onError(new TestException());

        ts.assertNoValues();
        ts.assertNotComplete();
        ts.assertError(TestException.class);
    }

    @Test
    public void delayAndTakeUntilNeverSubscribeToSource() {
        PublishProcessor<Integer> delayUntil = PublishProcessor.create();
        PublishProcessor<Integer> interrupt = PublishProcessor.create();
        final AtomicBoolean subscribed = new AtomicBoolean(false);

        Flowable.just(1)
        .doOnSubscribe(new Consumer<Object>() {
            @Override
            public void accept(Object o) {
                subscribed.set(true);
            }
        })
        .delaySubscription(delayUntil)
        .takeUntil(interrupt)
        .subscribe();

        interrupt.onNext(9000);
        delayUntil.onNext(1);

        Assert.assertFalse(subscribed.get());
    }

    @Test
    public void delayWithTimeDelayError() throws Exception {
        Flowable.just(1).concatWith(Flowable.<Integer>error(new TestException()))
        .delay(100, TimeUnit.MILLISECONDS, true)
        .test()
        .awaitDone(5, TimeUnit.SECONDS)
        .assertFailure(TestException.class, 1);
    }

    @Test
    public void delaySubscriptionDisposeBeforeTime() {
        Flowable<Integer> result = Flowable.just(1, 2, 3).delaySubscription(100, TimeUnit.MILLISECONDS, scheduler);

        Subscriber<Object> subscriber = TestHelper.mockSubscriber();
        TestSubscriber<Object> ts = new TestSubscriber<>(subscriber);

        result.subscribe(ts);
        ts.cancel();
        scheduler.advanceTimeBy(100, TimeUnit.MILLISECONDS);

        verify(subscriber, never()).onNext(any());
        verify(subscriber, never()).onComplete();
        verify(subscriber, never()).onError(any(Throwable.class));
    }

    @Test
    public void onErrorCalledOnScheduler() throws Exception {
        final CountDownLatch latch = new CountDownLatch(1);
        final AtomicReference<Thread> thread = new AtomicReference<>();

        Flowable.<String>error(new Exception())
                .delay(0, TimeUnit.MILLISECONDS, Schedulers.newThread())
                .doOnError(new Consumer<Throwable>() {
                    @Override
                    public void accept(Throwable throwable) throws Exception {
                        thread.set(Thread.currentThread());
                        latch.countDown();
                    }
                })
                .onErrorResumeWith(Flowable.<String>empty())
                .subscribe();

        latch.await();

        assertNotEquals(Thread.currentThread(), thread.get());
    }

    @Test
    public void dispose() {
        TestHelper.checkDisposed(PublishProcessor.create().delay(1, TimeUnit.SECONDS));

        TestHelper.checkDisposed(PublishProcessor.create().delay(Functions.justFunction(Flowable.never())));
    }

    @Test
    public void doubleOnSubscribe() {
        TestHelper.checkDoubleOnSubscribeFlowable(new Function<Flowable<Object>, Flowable<Object>>() {
            @Override
            public Flowable<Object> apply(Flowable<Object> f) throws Exception {
                return f.delay(1, TimeUnit.SECONDS);
            }
        });

        TestHelper.checkDoubleOnSubscribeFlowable(new Function<Flowable<Object>, Flowable<Object>>() {
            @Override
            public Flowable<Object> apply(Flowable<Object> f) throws Exception {
                return f.delay(Functions.justFunction(Flowable.never()));
            }
        });
    }

    @Test
    public void onCompleteFinal() {
        TestScheduler scheduler = new TestScheduler();

        Flowable.empty()
        .delay(1, TimeUnit.MILLISECONDS, scheduler)
        .subscribe(new DisposableSubscriber<Object>() {
            @Override
            public void onNext(Object value) {
            }

            @Override
            public void onError(Throwable e) {
            }

            @Override
            public void onComplete() {
                throw new TestException();
            }
        });

        try {
            scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
            fail("Should have thrown");
        } catch (TestException ex) {
            // expected
        }
    }

    @Test
    public void onErrorFinal() {
        TestScheduler scheduler = new TestScheduler();

        Flowable.error(new TestException())
        .delay(1, TimeUnit.MILLISECONDS, scheduler)
        .subscribe(new DisposableSubscriber<Object>() {
            @Override
            public void onNext(Object value) {
            }

            @Override
            public void onError(Throwable e) {
                throw new TestException();
            }

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

        try {
            scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
            fail("Should have thrown");
        } catch (TestException ex) {
            // expected
        }
    }

    @Test
    public void itemDelayReturnsNull() {
        Flowable.just(1).delay(new Function<Integer, Publisher<Object>>() {
            @Override
            public Publisher<Object> apply(Integer t) throws Exception {
                return null;
            }
        })
        .to(TestHelper.<Integer>testConsumer())
        .assertFailureAndMessage(NullPointerException.class, "The itemDelay returned a null Publisher");
    }

    @Test
    public void cancelShouldPreventRandomSubsequentEmissions() {
        for (int attempt = 1; attempt < 100; attempt ++) {

            @SuppressWarnings("resource")
            SequentialDisposable disposable = new SequentialDisposable();
            ConcurrentLinkedQueue<Integer> sink = new ConcurrentLinkedQueue<>();

            disposable.replace(
                Flowable.range(1, 10)
                .delay(1, TimeUnit.MICROSECONDS, Schedulers.computation(), true)
                .doOnNext(v -> {
                    if (v == 1) {
                        Schedulers.computation().scheduleDirect(disposable::dispose);
                    }
                    sink.offer(v);
                })
            .subscribe());

            LockSupport.parkNanos(TimeUnit.MILLISECONDS.toNanos(1));

            Integer last = null;

            while (!sink.isEmpty()) {
                Integer current = sink.poll();

                if (last != null && last + 1 != current) {
                    fail("Emission hole: " + last + " -> " + current);
                }

                last = current;
            }
        }
    }
}
