/*
 * 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.internal.operators.mixed;

import static org.junit.Assert.*;

import java.util.List;
import java.util.concurrent.atomic.AtomicReference;

import io.reactivex.rxjava3.disposables.Disposable;
import org.junit.Test;
import org.reactivestreams.*;

import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.exceptions.*;
import io.reactivex.rxjava3.functions.*;
import io.reactivex.rxjava3.internal.functions.Functions;
import io.reactivex.rxjava3.internal.subscriptions.BooleanSubscription;
import io.reactivex.rxjava3.plugins.RxJavaPlugins;
import io.reactivex.rxjava3.processors.PublishProcessor;
import io.reactivex.rxjava3.subjects.MaybeSubject;
import io.reactivex.rxjava3.subscribers.TestSubscriber;
import io.reactivex.rxjava3.testsupport.*;

public class FlowableSwitchMapMaybeTest extends RxJavaTest {

    @Test
    public void simple() {
        Flowable.range(1, 5)
        .switchMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                return Maybe.just(v);
            }
        })
        .test()
        .assertResult(1, 2, 3, 4, 5);
    }

    @Test
    public void simpleEmpty() {
        Flowable.range(1, 5)
        .switchMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                return Maybe.empty();
            }
        })
        .test()
        .assertResult();
    }

    @Test
    public void simpleMixed() {
        Flowable.range(1, 10)
        .switchMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                if (v % 2 == 0) {
                    return Maybe.just(v);
                }
                return Maybe.empty();
            }
        })
        .test()
        .assertResult(2, 4, 6, 8, 10);
    }

    @Test
    public void backpressured() {
        TestSubscriber<Integer> ts = Flowable.range(1, 1024)
        .switchMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                if (v % 2 == 0) {
                    return Maybe.just(v);
                }
                return Maybe.empty();
            }
        })
        .test(0L);

        // backpressure results items skipped
        ts
        .requestMore(1)
        .assertResult(1024);
    }

    @Test
    public void mainError() {
        Flowable.error(new TestException())
        .switchMapMaybe(Functions.justFunction(Maybe.never()))
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void innerError() {
        Flowable.just(1)
        .switchMapMaybe(Functions.justFunction(Maybe.error(new TestException())))
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void doubleOnSubscribe() {
        TestHelper.checkDoubleOnSubscribeFlowable(new Function<Flowable<Object>, Publisher<Object>>() {
            @Override
            public Publisher<Object> apply(Flowable<Object> f)
                    throws Exception {
                return f
                        .switchMapMaybe(Functions.justFunction(Maybe.never()));
            }
        }
        );
    }

    @Test
    public void limit() {
        Flowable.range(1, 5)
        .switchMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                return Maybe.just(v);
            }
        })
        .take(3)
        .test()
        .assertResult(1, 2, 3);
    }

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

        final MaybeSubject<Integer> ms1 = MaybeSubject.create();
        final MaybeSubject<Integer> ms2 = MaybeSubject.create();

        TestSubscriber<Integer> ts = pp.switchMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                        if (v == 1) {
                            return ms1;
                        }
                        return ms2;
                    }
        }).test();

        ts.assertEmpty();

        pp.onNext(1);

        ts.assertEmpty();

        assertTrue(ms1.hasObservers());

        pp.onNext(2);

        assertFalse(ms1.hasObservers());
        assertTrue(ms2.hasObservers());

        ms2.onError(new TestException());

        assertFalse(pp.hasSubscribers());

        ts.assertFailure(TestException.class);
    }

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

        final MaybeSubject<Integer> ms1 = MaybeSubject.create();
        final MaybeSubject<Integer> ms2 = MaybeSubject.create();

        TestSubscriber<Integer> ts = pp.switchMapMaybeDelayError(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                        if (v == 1) {
                            return ms1;
                        }
                        return ms2;
                    }
        }).test();

        ts.assertEmpty();

        pp.onNext(1);

        ts.assertEmpty();

        assertTrue(ms1.hasObservers());

        pp.onNext(2);

        assertFalse(ms1.hasObservers());
        assertTrue(ms2.hasObservers());

        ms2.onError(new TestException());

        ts.assertEmpty();

        assertTrue(pp.hasSubscribers());

        pp.onComplete();

        ts.assertFailure(TestException.class);
    }

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

        final MaybeSubject<Integer> ms = MaybeSubject.create();

        TestSubscriber<Integer> ts = pp.switchMapMaybeDelayError(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                        return ms;
                    }
        }).test();

        ts.assertEmpty();

        pp.onNext(1);

        ts.assertEmpty();

        assertTrue(ms.hasObservers());

        pp.onError(new TestException());

        assertTrue(ms.hasObservers());

        ts.assertEmpty();

        ms.onComplete();

        ts.assertFailure(TestException.class);
    }

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

        final MaybeSubject<Integer> ms = MaybeSubject.create();

        TestSubscriber<Integer> ts = pp.switchMapMaybeDelayError(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                        return ms;
                    }
        }).test();

        ts.assertEmpty();

        pp.onNext(1);

        ts.assertEmpty();

        assertTrue(ms.hasObservers());

        pp.onError(new TestException());

        assertTrue(ms.hasObservers());

        ts.assertEmpty();

        ms.onSuccess(1);

        ts.assertFailure(TestException.class, 1);
    }

    @Test
    public void mapperCrash() {
        Flowable.just(1)
        .switchMapMaybe(new Function<Integer, MaybeSource<? extends Object>>() {
            @Override
            public MaybeSource<? extends Object> apply(Integer v)
                    throws Exception {
                        throw new TestException();
                    }
        })
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void disposeBeforeSwitchInOnNext() {
        final TestSubscriber<Integer> ts = new TestSubscriber<>();

        Flowable.just(1)
        .switchMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                        ts.cancel();
                        return Maybe.just(1);
                    }
        }).subscribe(ts);

        ts.assertEmpty();
    }

    @Test
    public void disposeOnNextAfterFirst() {
        final TestSubscriber<Integer> ts = new TestSubscriber<>();

        Flowable.just(1, 2)
        .switchMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                if (v == 2) {
                    ts.cancel();
                }
                return Maybe.just(1);
            }
        }).subscribe(ts);

        ts.assertValue(1)
        .assertNoErrors()
        .assertNotComplete();
    }

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

        final MaybeSubject<Integer> ms = MaybeSubject.create();

        TestSubscriber<Integer> ts = pp.switchMapMaybeDelayError(new Function<Integer, MaybeSource<Integer>>() {
            @Override
            public MaybeSource<Integer> apply(Integer v)
                    throws Exception {
                        return ms;
                    }
        }).test();

        ts.assertEmpty();

        pp.onNext(1);

        ts.assertEmpty();

        assertTrue(pp.hasSubscribers());
        assertTrue(ms.hasObservers());

        ts.cancel();

        assertFalse(pp.hasSubscribers());
        assertFalse(ms.hasObservers());
    }

    @Test
    public void mainErrorAfterTermination() {
        List<Throwable> errors = TestHelper.trackPluginErrors();
        try {
            new Flowable<Integer>() {
                @Override
                protected void subscribeActual(Subscriber<? super Integer> s) {
                    s.onSubscribe(new BooleanSubscription());
                    s.onNext(1);
                    s.onError(new TestException("outer"));
                }
            }
            .switchMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
                @Override
                public MaybeSource<Integer> apply(Integer v)
                        throws Exception {
                    return Maybe.error(new TestException("inner"));
                }
            })
            .to(TestHelper.<Integer>testConsumer())
            .assertFailureAndMessage(TestException.class, "inner");

            TestHelper.assertUndeliverable(errors, 0, TestException.class, "outer");
        } finally {
            RxJavaPlugins.reset();
        }
    }

    @Test
    public void innerErrorAfterTermination() {
        List<Throwable> errors = TestHelper.trackPluginErrors();
        try {
            final AtomicReference<MaybeObserver<? super Integer>> moRef = new AtomicReference<>();

            TestSubscriberEx<Integer> ts = new Flowable<Integer>() {
                @Override
                protected void subscribeActual(Subscriber<? super Integer> s) {
                    s.onSubscribe(new BooleanSubscription());
                    s.onNext(1);
                    s.onError(new TestException("outer"));
                }
            }
            .switchMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
                @Override
                public MaybeSource<Integer> apply(Integer v)
                        throws Exception {
                    return new Maybe<Integer>() {
                        @Override
                        protected void subscribeActual(
                                MaybeObserver<? super Integer> observer) {
                            observer.onSubscribe(Disposable.empty());
                            moRef.set(observer);
                        }
                    };
                }
            })
            .to(TestHelper.<Integer>testConsumer());

            ts.assertFailureAndMessage(TestException.class, "outer");

            moRef.get().onError(new TestException("inner"));
            moRef.get().onComplete();

            TestHelper.assertUndeliverable(errors, 0, TestException.class, "inner");
        } finally {
            RxJavaPlugins.reset();
        }
    }

    @Test
    public void nextCancelRace() {
        for (int i = 0; i < TestHelper.RACE_LONG_LOOPS; i++) {

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

            final MaybeSubject<Integer> ms = MaybeSubject.create();

            final TestSubscriber<Integer> ts = pp.switchMapMaybeDelayError(new Function<Integer, MaybeSource<Integer>>() {
                @Override
                public MaybeSource<Integer> apply(Integer v)
                        throws Exception {
                            return ms;
                        }
            }).test();

            Runnable r1 = new Runnable() {
                @Override
                public void run() {
                    pp.onNext(1);
                }
            };

            Runnable r2 = new Runnable() {
                @Override
                public void run() {
                    ts.cancel();
                }
            };

            TestHelper.race(r1, r2);

            ts.assertNoErrors()
            .assertNotComplete();
        }
    }

    @Test
    public void nextInnerErrorRace() {
        final TestException ex = new TestException();

        for (int i = 0; i < TestHelper.RACE_LONG_LOOPS; i++) {

            List<Throwable> errors = TestHelper.trackPluginErrors();
            try {
                final PublishProcessor<Integer> pp = PublishProcessor.create();

                final MaybeSubject<Integer> ms = MaybeSubject.create();

                final TestSubscriberEx<Integer> ts = pp.switchMapMaybeDelayError(new Function<Integer, MaybeSource<Integer>>() {
                    @Override
                    public MaybeSource<Integer> apply(Integer v)
                            throws Exception {
                        if (v == 1) {
                            return ms;
                        }
                        return Maybe.never();
                    }
                }).to(TestHelper.<Integer>testConsumer());

                pp.onNext(1);

                Runnable r1 = new Runnable() {
                    @Override
                    public void run() {
                        pp.onNext(2);
                    }
                };

                Runnable r2 = new Runnable() {
                    @Override
                    public void run() {
                        ms.onError(ex);
                    }
                };

                TestHelper.race(r1, r2);

                if (ts.errors().size() != 0) {
                    assertTrue(errors.isEmpty());
                    ts.assertFailure(TestException.class);
                } else if (!errors.isEmpty()) {
                    TestHelper.assertUndeliverable(errors, 0, TestException.class);
                }
            } finally {
                RxJavaPlugins.reset();
            }
        }
    }

    @Test
    public void mainErrorInnerErrorRace() {
        final TestException ex = new TestException();
        final TestException ex2 = new TestException();

        for (int i = 0; i < TestHelper.RACE_LONG_LOOPS; i++) {

            List<Throwable> errors = TestHelper.trackPluginErrors();
            try {
                final PublishProcessor<Integer> pp = PublishProcessor.create();

                final MaybeSubject<Integer> ms = MaybeSubject.create();

                final TestSubscriber<Integer> ts = pp.switchMapMaybeDelayError(new Function<Integer, MaybeSource<Integer>>() {
                    @Override
                    public MaybeSource<Integer> apply(Integer v)
                            throws Exception {
                        if (v == 1) {
                            return ms;
                        }
                        return Maybe.never();
                    }
                }).test();

                pp.onNext(1);

                Runnable r1 = new Runnable() {
                    @Override
                    public void run() {
                        pp.onError(ex);
                    }
                };

                Runnable r2 = new Runnable() {
                    @Override
                    public void run() {
                        ms.onError(ex2);
                    }
                };

                TestHelper.race(r1, r2);

                ts.assertError(new Predicate<Throwable>() {
                    @Override
                    public boolean test(Throwable e) throws Exception {
                        return e instanceof TestException || e instanceof CompositeException;
                    }
                });

                if (!errors.isEmpty()) {
                    TestHelper.assertUndeliverable(errors, 0, TestException.class);
                }
            } finally {
                RxJavaPlugins.reset();
            }
        }
    }

    @Test
    public void nextInnerSuccessRace() {
        for (int i = 0; i < TestHelper.RACE_LONG_LOOPS; i++) {

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

            final MaybeSubject<Integer> ms = MaybeSubject.create();

            final TestSubscriber<Integer> ts = pp.switchMapMaybeDelayError(new Function<Integer, MaybeSource<Integer>>() {
                @Override
                public MaybeSource<Integer> apply(Integer v)
                        throws Exception {
                    if (v == 1) {
                            return ms;
                    }
                    return Maybe.empty();
                }
            }).test();

            pp.onNext(1);

            Runnable r1 = new Runnable() {
                @Override
                public void run() {
                    pp.onNext(2);
                }
            };

            Runnable r2 = new Runnable() {
                @Override
                public void run() {
                    ms.onSuccess(3);
                }
            };

            TestHelper.race(r1, r2);

            ts.assertNoErrors()
            .assertNotComplete();
        }
    }

    @Test
    public void requestMoreOnNext() {
        TestSubscriber<Integer> ts = new TestSubscriber<Integer>(1) {
            @Override
            public void onNext(Integer t) {
                super.onNext(t);
                requestMore(1);
            }
        };
        Flowable.range(1, 5)
        .switchMapMaybe(Functions.justFunction(Maybe.just(1)))
        .subscribe(ts);

        ts.assertResult(1, 1, 1, 1, 1);
    }

    @Test
    public void undeliverableUponCancel() {
        TestHelper.checkUndeliverableUponCancel(new FlowableConverter<Integer, Flowable<Integer>>() {
            @Override
            public Flowable<Integer> apply(Flowable<Integer> upstream) {
                return upstream.switchMapMaybe(new Function<Integer, Maybe<Integer>>() {
                    @Override
                    public Maybe<Integer> apply(Integer v) throws Throwable {
                        return Maybe.just(v).hide();
                    }
                });
            }
        });
    }

    @Test
    public void undeliverableUponCancelDelayError() {
        TestHelper.checkUndeliverableUponCancel(new FlowableConverter<Integer, Flowable<Integer>>() {
            @Override
            public Flowable<Integer> apply(Flowable<Integer> upstream) {
                return upstream.switchMapMaybeDelayError(new Function<Integer, Maybe<Integer>>() {
                    @Override
                    public Maybe<Integer> apply(Integer v) throws Throwable {
                        return Maybe.just(v).hide();
                    }
                });
            }
        });
    }
}
