/**
 * 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.rxjava3.subjects;

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

import java.util.ArrayList;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import org.junit.Test;
import org.mockito.*;

import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.disposables.Disposable;
import io.reactivex.rxjava3.exceptions.TestException;
import io.reactivex.rxjava3.functions.*;
import io.reactivex.rxjava3.observers.*;
import io.reactivex.rxjava3.testsupport.*;

public class PublishSubjectTest extends SubjectTest<Integer> {

    @Override
    protected Subject<Integer> create() {
        return PublishSubject.create();
    }

    @Test
    @SuppressUndeliverable
    public void completed() {
        PublishSubject<String> subject = PublishSubject.create();

        Observer<String> observer = TestHelper.mockObserver();
        subject.subscribe(observer);

        subject.onNext("one");
        subject.onNext("two");
        subject.onNext("three");
        subject.onComplete();

        Observer<String> anotherSubscriber = TestHelper.mockObserver();
        subject.subscribe(anotherSubscriber);

        subject.onNext("four");
        subject.onComplete();
        subject.onError(new Throwable());

        assertCompletedSubscriber(observer);
        // todo bug?            assertNeverSubscriber(anotherSubscriber);
    }

    @Test
    public void completedStopsEmittingData() {
        PublishSubject<Object> channel = PublishSubject.create();
        Observer<Object> observerA = TestHelper.mockObserver();
        Observer<Object> observerB = TestHelper.mockObserver();
        Observer<Object> observerC = TestHelper.mockObserver();

        TestObserver<Object> to = new TestObserver<>(observerA);

        channel.subscribe(to);
        channel.subscribe(observerB);

        InOrder inOrderA = inOrder(observerA);
        InOrder inOrderB = inOrder(observerB);
        InOrder inOrderC = inOrder(observerC);

        channel.onNext(42);

        inOrderA.verify(observerA).onNext(42);
        inOrderB.verify(observerB).onNext(42);

        to.dispose();
        inOrderA.verifyNoMoreInteractions();

        channel.onNext(4711);

        inOrderB.verify(observerB).onNext(4711);

        channel.onComplete();

        inOrderB.verify(observerB).onComplete();

        channel.subscribe(observerC);

        inOrderC.verify(observerC).onComplete();

        channel.onNext(13);

        inOrderB.verifyNoMoreInteractions();
        inOrderC.verifyNoMoreInteractions();
    }

    private void assertCompletedSubscriber(Observer<String> observer) {
        verify(observer, times(1)).onNext("one");
        verify(observer, times(1)).onNext("two");
        verify(observer, times(1)).onNext("three");
        verify(observer, Mockito.never()).onError(any(Throwable.class));
        verify(observer, times(1)).onComplete();
    }

    @Test
    @SuppressUndeliverable
    public void error() {
        PublishSubject<String> subject = PublishSubject.create();

        Observer<String> observer = TestHelper.mockObserver();
        subject.subscribe(observer);

        subject.onNext("one");
        subject.onNext("two");
        subject.onNext("three");
        subject.onError(testException);

        Observer<String> anotherSubscriber = TestHelper.mockObserver();
        subject.subscribe(anotherSubscriber);

        subject.onNext("four");
        subject.onError(new Throwable());
        subject.onComplete();

        assertErrorSubscriber(observer);
        // todo bug?            assertNeverSubscriber(anotherSubscriber);
    }

    private void assertErrorSubscriber(Observer<String> observer) {
        verify(observer, times(1)).onNext("one");
        verify(observer, times(1)).onNext("two");
        verify(observer, times(1)).onNext("three");
        verify(observer, times(1)).onError(testException);
        verify(observer, Mockito.never()).onComplete();
    }

    @Test
    public void subscribeMidSequence() {
        PublishSubject<String> subject = PublishSubject.create();

        Observer<String> observer = TestHelper.mockObserver();
        subject.subscribe(observer);

        subject.onNext("one");
        subject.onNext("two");

        assertObservedUntilTwo(observer);

        Observer<String> anotherSubscriber = TestHelper.mockObserver();
        subject.subscribe(anotherSubscriber);

        subject.onNext("three");
        subject.onComplete();

        assertCompletedSubscriber(observer);
        assertCompletedStartingWithThreeSubscriber(anotherSubscriber);
    }

    private void assertCompletedStartingWithThreeSubscriber(Observer<String> observer) {
        verify(observer, Mockito.never()).onNext("one");
        verify(observer, Mockito.never()).onNext("two");
        verify(observer, times(1)).onNext("three");
        verify(observer, Mockito.never()).onError(any(Throwable.class));
        verify(observer, times(1)).onComplete();
    }

    @Test
    public void unsubscribeFirstSubscriber() {
        PublishSubject<String> subject = PublishSubject.create();

        Observer<String> observer = TestHelper.mockObserver();
        TestObserver<String> to = new TestObserver<>(observer);
        subject.subscribe(to);

        subject.onNext("one");
        subject.onNext("two");

        to.dispose();
        assertObservedUntilTwo(observer);

        Observer<String> anotherSubscriber = TestHelper.mockObserver();
        subject.subscribe(anotherSubscriber);

        subject.onNext("three");
        subject.onComplete();

        assertObservedUntilTwo(observer);
        assertCompletedStartingWithThreeSubscriber(anotherSubscriber);
    }

    private void assertObservedUntilTwo(Observer<String> observer) {
        verify(observer, times(1)).onNext("one");
        verify(observer, times(1)).onNext("two");
        verify(observer, Mockito.never()).onNext("three");
        verify(observer, Mockito.never()).onError(any(Throwable.class));
        verify(observer, Mockito.never()).onComplete();
    }

    @Test
    public void nestedSubscribe() {
        final PublishSubject<Integer> s = PublishSubject.create();

        final AtomicInteger countParent = new AtomicInteger();
        final AtomicInteger countChildren = new AtomicInteger();
        final AtomicInteger countTotal = new AtomicInteger();

        final ArrayList<String> list = new ArrayList<>();

        s.flatMap(new Function<Integer, Observable<String>>() {

            @Override
            public Observable<String> apply(final Integer v) {
                countParent.incrementAndGet();

                // then subscribe to subject again (it will not receive the previous value)
                return s.map(new Function<Integer, String>() {

                    @Override
                    public String apply(Integer v2) {
                        countChildren.incrementAndGet();
                        return "Parent: " + v + " Child: " + v2;
                    }

                });
            }

        }).subscribe(new Consumer<String>() {

            @Override
            public void accept(String v) {
                countTotal.incrementAndGet();
                list.add(v);
            }

        });

        for (int i = 0; i < 10; i++) {
            s.onNext(i);
        }
        s.onComplete();

        //            System.out.println("countParent: " + countParent.get());
        //            System.out.println("countChildren: " + countChildren.get());
        //            System.out.println("countTotal: " + countTotal.get());

        // 9+8+7+6+5+4+3+2+1+0 == 45
        assertEquals(45, list.size());
    }

    /**
     * Should be able to unsubscribe all Subscribers, have it stop emitting, then subscribe new ones and it start emitting again.
     */
    @Test
    public void reSubscribe() {
        final PublishSubject<Integer> ps = PublishSubject.create();

        Observer<Integer> o1 = TestHelper.mockObserver();
        TestObserver<Integer> to = new TestObserver<>(o1);
        ps.subscribe(to);

        // emit
        ps.onNext(1);

        // validate we got it
        InOrder inOrder1 = inOrder(o1);
        inOrder1.verify(o1, times(1)).onNext(1);
        inOrder1.verifyNoMoreInteractions();

        // unsubscribe
        to.dispose();

        // emit again but nothing will be there to receive it
        ps.onNext(2);

        Observer<Integer> o2 = TestHelper.mockObserver();
        TestObserver<Integer> to2 = new TestObserver<>(o2);
        ps.subscribe(to2);

        // emit
        ps.onNext(3);

        // validate we got it
        InOrder inOrder2 = inOrder(o2);
        inOrder2.verify(o2, times(1)).onNext(3);
        inOrder2.verifyNoMoreInteractions();

        to2.dispose();
    }

    private final Throwable testException = new Throwable();

    @Test
    public void unsubscriptionCase() {
        PublishSubject<String> src = PublishSubject.create();

        for (int i = 0; i < 10; i++) {
            final Observer<Object> o = TestHelper.mockObserver();
            InOrder inOrder = inOrder(o);
            String v = "" + i;
            System.out.printf("Turn: %d%n", i);
            src.firstElement()
                .toObservable()
                .flatMap(new Function<String, Observable<String>>() {

                    @Override
                    public Observable<String> apply(String t1) {
                        return Observable.just(t1 + ", " + t1);
                    }
                })
                .subscribe(new DefaultObserver<String>() {
                    @Override
                    public void onNext(String t) {
                        o.onNext(t);
                    }

                    @Override
                    public void onError(Throwable e) {
                        o.onError(e);
                    }

                    @Override
                    public void onComplete() {
                        o.onComplete();
                    }
                });
            src.onNext(v);

            inOrder.verify(o).onNext(v + ", " + v);
            inOrder.verify(o).onComplete();
            verify(o, never()).onError(any(Throwable.class));
        }
    }

    @Test
    public void currentStateMethodsNormal() {
        PublishSubject<Object> as = PublishSubject.create();

        assertFalse(as.hasThrowable());
        assertFalse(as.hasComplete());
        assertNull(as.getThrowable());

        as.onNext(1);

        assertFalse(as.hasThrowable());
        assertFalse(as.hasComplete());
        assertNull(as.getThrowable());

        as.onComplete();

        assertFalse(as.hasThrowable());
        assertTrue(as.hasComplete());
        assertNull(as.getThrowable());
    }

    @Test
    public void currentStateMethodsEmpty() {
        PublishSubject<Object> as = PublishSubject.create();

        assertFalse(as.hasThrowable());
        assertFalse(as.hasComplete());
        assertNull(as.getThrowable());

        as.onComplete();

        assertFalse(as.hasThrowable());
        assertTrue(as.hasComplete());
        assertNull(as.getThrowable());
    }

    @Test
    public void currentStateMethodsError() {
        PublishSubject<Object> as = PublishSubject.create();

        assertFalse(as.hasThrowable());
        assertFalse(as.hasComplete());
        assertNull(as.getThrowable());

        as.onError(new TestException());

        assertTrue(as.hasThrowable());
        assertFalse(as.hasComplete());
        assertTrue(as.getThrowable() instanceof TestException);
    }

    @Test
    public void crossCancel() {
        final TestObserver<Integer> to1 = new TestObserver<>();
        TestObserver<Integer> to2 = new TestObserver<Integer>() {
            @Override
            public void onNext(Integer t) {
                super.onNext(t);
                to1.dispose();
            }
        };

        PublishSubject<Integer> ps = PublishSubject.create();

        ps.subscribe(to2);
        ps.subscribe(to1);

        ps.onNext(1);

        to2.assertValue(1);

        to1.assertNoValues();
    }

    @Test
    @SuppressUndeliverable
    public void crossCancelOnError() {
        final TestObserver<Integer> to1 = new TestObserver<>();
        TestObserver<Integer> to2 = new TestObserver<Integer>() {
            @Override
            public void onError(Throwable t) {
                super.onError(t);
                to1.dispose();
            }
        };

        PublishSubject<Integer> ps = PublishSubject.create();

        ps.subscribe(to2);
        ps.subscribe(to1);

        ps.onError(new TestException());

        to2.assertError(TestException.class);

        to1.assertNoErrors();
    }

    @Test
    public void crossCancelOnComplete() {
        final TestObserver<Integer> to1 = new TestObserver<>();
        TestObserver<Integer> to2 = new TestObserver<Integer>() {
            @Override
            public void onComplete() {
                super.onComplete();
                to1.dispose();
            }
        };

        PublishSubject<Integer> ps = PublishSubject.create();

        ps.subscribe(to2);
        ps.subscribe(to1);

        ps.onComplete();

        to2.assertComplete();

        to1.assertNotComplete();
    }

    @Test
    public void onSubscribeCancelsImmediately() {
        PublishSubject<Integer> ps = PublishSubject.create();

        TestObserver<Integer> to = ps.test();

        ps.subscribe(new Observer<Integer>() {

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

            @Override
            public void onNext(Integer t) {

            }

            @Override
            public void onError(Throwable t) {

            }

            @Override
            public void onComplete() {

            }

        });

        to.dispose();

        assertFalse(ps.hasObservers());
    }

    @Test
    public void terminateRace() throws Exception {

        for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
            final PublishSubject<Integer> ps = PublishSubject.create();

            TestObserver<Integer> to = ps.test();

            Runnable task = new Runnable() {
                @Override
                public void run() {
                    ps.onComplete();
                }
            };

            TestHelper.race(task, task);

            to
            .awaitDone(5, TimeUnit.SECONDS)
            .assertResult();
        }
    }

    @Test
    public void addRemoveRance() throws Exception {

        for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
            final PublishSubject<Integer> ps = PublishSubject.create();

            final TestObserver<Integer> to = ps.test();

            Runnable r1 = new Runnable() {
                @Override
                public void run() {
                    ps.subscribe();
                }
            };
            Runnable r2 = new Runnable() {
                @Override
                public void run() {
                    to.dispose();
                }
            };

            TestHelper.race(r1, r2);
        }
    }

    @Test
    public void addTerminateRance() throws Exception {

        for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
            final PublishSubject<Integer> ps = PublishSubject.create();

            Runnable r1 = new Runnable() {
                @Override
                public void run() {
                    ps.subscribe();
                }
            };
            Runnable r2 = new Runnable() {
                @Override
                public void run() {
                    ps.onComplete();
                }
            };

            TestHelper.race(r1, r2);
        }
    }

    @Test
    public void addCompleteRance() throws Exception {

        for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
            final PublishSubject<Integer> ps = PublishSubject.create();

            final TestObserver<Integer> to = new TestObserver<>();

            Runnable r1 = new Runnable() {
                @Override
                public void run() {
                    ps.subscribe(to);
                }
            };
            Runnable r2 = new Runnable() {
                @Override
                public void run() {
                    ps.onComplete();
                }
            };

            TestHelper.race(r1, r2);

            to.awaitDone(5, TimeUnit.SECONDS)
            .assertResult();
        }
    }

    @Test
    public void subscribeToAfterComplete() {
        PublishSubject<Integer> ps = PublishSubject.create();

        ps.onComplete();

        PublishSubject<Integer> ps2 = PublishSubject.create();

        ps2.subscribe(ps);

        assertFalse(ps2.hasObservers());
    }

    @Test
    public void subscribedTo() {
        PublishSubject<Integer> ps = PublishSubject.create();
        PublishSubject<Integer> ps2 = PublishSubject.create();

        ps.subscribe(ps2);

        TestObserver<Integer> to = ps2.test();

        ps.onNext(1);
        ps.onNext(2);
        ps.onComplete();

        to.assertResult(1, 2);
    }
}