/*
 * 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.observable;

import static org.junit.Assert.*;

import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.atomic.AtomicInteger;

import org.junit.Test;

import io.reactivex.rxjava4.core.*;
import io.reactivex.rxjava4.disposables.Disposable;
import io.reactivex.rxjava4.exceptions.*;
import io.reactivex.rxjava4.functions.*;
import io.reactivex.rxjava4.internal.functions.Functions;
import io.reactivex.rxjava4.internal.operators.observable.ObservableConcatMapSchedulerTest.EmptyDisposingObservable;
import io.reactivex.rxjava4.observers.TestObserver;
import io.reactivex.rxjava4.plugins.RxJavaPlugins;
import io.reactivex.rxjava4.subjects.*;
import io.reactivex.rxjava4.testsupport.TestHelper;

public class ObservableConcatMapTest extends RxJavaTest {

    @Test
    public void asyncFused() {
        UnicastSubject<Integer> us = UnicastSubject.create();

        TestObserver<Integer> to = us.concatMap(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.range(v, 2);
            }
        })
        .test();

        us.onNext(1);
        us.onComplete();

        to.assertResult(1, 2);
    }

    @Test
    public void dispose() {
        TestHelper.checkDisposed(Observable.<Integer>just(1).hide()
        .concatMap(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.error(new TestException());
            }
        }));
    }

    @Test
    public void dispose2() {
        TestHelper.checkDisposed(Observable.<Integer>just(1).hide()
        .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.error(new TestException());
            }
        }));
    }

    @Test
    public void mainError() {
        Observable.<Integer>error(new TestException())
        .concatMap(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.range(v, 2);
            }
        })
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void innerError() {
        Observable.<Integer>just(1).hide()
        .concatMap(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.error(new TestException());
            }
        })
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void mainErrorDelayed() {
        Observable.<Integer>error(new TestException())
        .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.range(v, 2);
            }
        })
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void innerErrorDelayError() {
        Observable.<Integer>just(1).hide()
        .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.error(new TestException());
            }
        })
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void innerErrorDelayError2() {
        Observable.<Integer>just(1).hide()
        .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.fromCallable(new Callable<Integer>() {
                    @Override
                    public Integer call() throws Exception {
                        throw new TestException();
                    }
                });
            }
        })
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void badSource() {
        List<Throwable> errors = TestHelper.trackPluginErrors();
        try {
            new Observable<Integer>() {
                @Override
                protected void subscribeActual(Observer<? super Integer> observer) {
                    observer.onSubscribe(Disposable.empty());

                    observer.onNext(1);
                    observer.onComplete();
                    observer.onNext(2);
                    observer.onError(new TestException());
                    observer.onComplete();
                }
            }
            .concatMap(new Function<Integer, ObservableSource<Integer>>() {
                @Override
                public ObservableSource<Integer> apply(Integer v) throws Exception {
                    return Observable.range(v, 2);
                }
            })
            .test()
            .assertResult(1, 2);

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

    @Test
    public void badSourceDelayError() {
        List<Throwable> errors = TestHelper.trackPluginErrors();
        try {
            new Observable<Integer>() {
                @Override
                protected void subscribeActual(Observer<? super Integer> observer) {
                    observer.onSubscribe(Disposable.empty());

                    observer.onNext(1);
                    observer.onComplete();
                    observer.onNext(2);
                    observer.onError(new TestException());
                    observer.onComplete();
                }
            }
            .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
                @Override
                public ObservableSource<Integer> apply(Integer v) throws Exception {
                    return Observable.range(v, 2);
                }
            })
            .test()
            .assertResult(1, 2);

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

    @Test
    public void normalDelayErrors() {
        Observable.just(1).hide()
        .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.range(v, 2);
            }
        })
        .test()
        .assertResult(1, 2);
    }

    @Test
    public void normalDelayErrorsTillTheEnd() {
        Observable.just(1).hide()
        .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.range(v, 2);
            }
        }, true, 16)
        .test()
        .assertResult(1, 2);
    }

    @Test
    public void onErrorRace() {
        for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
            List<Throwable> errors = TestHelper.trackPluginErrors();
            try {
                final PublishSubject<Integer> ps1 = PublishSubject.create();
                final PublishSubject<Integer> ps2 = PublishSubject.create();

                TestObserver<Integer> to = ps1.concatMap(new Function<Integer, ObservableSource<Integer>>() {
                    @Override
                    public ObservableSource<Integer> apply(Integer v) throws Exception {
                        return ps2;
                    }
                }).test();

                final TestException ex1 = new TestException();
                final TestException ex2 = new TestException();

                Runnable r1 = new Runnable() {
                    @Override
                    public void run() {
                        ps1.onError(ex1);
                    }
                };
                Runnable r2 = new Runnable() {
                    @Override
                    public void run() {
                        ps2.onError(ex2);
                    }
                };

                TestHelper.race(r1, r2);

                to.assertFailure(TestException.class);

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

    @Test
    public void mapperThrows() {
        Observable.just(1).hide()
        .concatMap(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                throw new TestException();
            }
        })
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void fusedPollThrows() {
        Observable.just(1)
        .map(new Function<Integer, Integer>() {
            @Override
            public Integer apply(Integer v) throws Exception {
                throw new TestException();
            }
        })
        .concatMap(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.range(v, 2);
            }
        })
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void fusedPollThrowsDelayError() {
        Observable.just(1)
        .map(new Function<Integer, Integer>() {
            @Override
            public Integer apply(Integer v) throws Exception {
                throw new TestException();
            }
        })
        .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.range(v, 2);
            }
        })
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void mapperThrowsDelayError() {
        Observable.just(1).hide()
        .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                throw new TestException();
            }
        })
        .test()
        .assertFailure(TestException.class);
    }

    @Test
    public void badInnerDelayError() {
        @SuppressWarnings("rawtypes")
        final Observer[] o = { null };

        List<Throwable> errors = TestHelper.trackPluginErrors();

        try {
            Observable.just(1).hide()
            .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
                @Override
                public ObservableSource<Integer> apply(Integer v) throws Exception {
                    return new Observable<Integer>() {
                        @Override
                        protected void subscribeActual(Observer<? super Integer> observer) {
                            o[0] = observer;
                            observer.onSubscribe(Disposable.empty());
                            observer.onComplete();
                        }
                    };
                }
            })
            .test()
            .assertResult();

            o[0].onError(new TestException());

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

    @Test
    public void concatReportsDisposedOnComplete() {
        final Disposable[] disposable = { null };

        Observable.fromArray(Observable.just(1), Observable.just(2))
        .hide()
        .concatMap(Functions.<Observable<Integer>>identity())
        .subscribe(new Observer<Integer>() {

            @Override
            public void onSubscribe(Disposable d) {
                disposable[0] = d;
            }

            @Override
            public void onNext(Integer t) {
            }

            @Override
            public void onError(Throwable e) {
            }

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

        assertTrue(disposable[0].isDisposed());
    }

    @Test
    public void concatReportsDisposedOnError() {
        final Disposable[] disposable = { null };

        Observable.fromArray(Observable.just(1), Observable.<Integer>error(new TestException()))
        .hide()
        .concatMap(Functions.<Observable<Integer>>identity())
        .subscribe(new Observer<Integer>() {

            @Override
            public void onSubscribe(Disposable d) {
                disposable[0] = d;
            }

            @Override
            public void onNext(Integer t) {
            }

            @Override
            public void onError(Throwable e) {
            }

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

        assertTrue(disposable[0].isDisposed());
    }

    @Test
    public void reentrantNoOverflow() {
        List<Throwable> errors = TestHelper.trackPluginErrors();
        try {
            final PublishSubject<Integer> ps = PublishSubject.create();

            TestObserver<Integer> to = ps.concatMap(new Function<Integer, Observable<Integer>>() {
                @Override
                public Observable<Integer> apply(Integer v)
                        throws Exception {
                    return Observable.just(v + 1);
                }
            }, 1)
            .subscribeWith(new TestObserver<Integer>() {
                @Override
                public void onNext(Integer t) {
                    super.onNext(t);
                    if (t == 1) {
                        for (int i = 1; i < 10; i++) {
                            ps.onNext(i);
                        }
                        ps.onComplete();
                    }
                }
            });

            ps.onNext(0);

            if (!errors.isEmpty()) {
                to.onError(new CompositeException(errors));
            }

            to.assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
        } finally {
            RxJavaPlugins.reset();
        }
    }

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

        TestObserver<Integer> to = ps.concatMap(new Function<Integer, Observable<Integer>>() {
            @Override
            public Observable<Integer> apply(Integer v)
                    throws Exception {
                return Observable.just(v + 1).hide();
            }
        }, 1)
        .subscribeWith(new TestObserver<Integer>() {
            @Override
            public void onNext(Integer t) {
                super.onNext(t);
                if (t == 1) {
                    for (int i = 1; i < 10; i++) {
                        ps.onNext(i);
                    }
                    ps.onComplete();
                }
            }
        });

        ps.onNext(0);

        to.assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
    }

    @Test
    public void noCancelPrevious() {
        final AtomicInteger counter = new AtomicInteger();

        Observable.range(1, 5)
        .concatMap(new Function<Integer, ObservableSource<Integer>>() {
            @Override
            public ObservableSource<Integer> apply(Integer v) throws Exception {
                return Observable.just(v).doOnDispose(new Action() {
                    @Override
                    public void run() throws Exception {
                        counter.getAndIncrement();
                    }
                });
            }
        })
        .test()
        .assertResult(1, 2, 3, 4, 5);

        assertEquals(0, counter.get());
    }

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

    @Test
    public void undeliverableUponCancelDelayError() {
        TestHelper.checkUndeliverableUponCancel(new ObservableConverter<Integer, Observable<Integer>>() {
            @Override
            public Observable<Integer> apply(Observable<Integer> upstream) {
                return upstream.concatMapDelayError(new Function<Integer, Observable<Integer>>() {
                    @Override
                    public Observable<Integer> apply(Integer v) throws Throwable {
                        return Observable.just(v).hide();
                    }
                }, false, 2);
            }
        });
    }

    @Test
    public void undeliverableUponCancelDelayErrorTillEnd() {
        TestHelper.checkUndeliverableUponCancel(new ObservableConverter<Integer, Observable<Integer>>() {
            @Override
            public Observable<Integer> apply(Observable<Integer> upstream) {
                return upstream.concatMapDelayError(new Function<Integer, Observable<Integer>>() {
                    @Override
                    public Observable<Integer> apply(Integer v) throws Throwable {
                        return Observable.just(v).hide();
                    }
                }, true, 2);
            }
        });
    }

    @Test
    public void doubleOnSubscribe() {
        TestHelper.checkDoubleOnSubscribeObservable(o -> o.concatMap(_ -> Observable.never()));
    }

    @Test
    public void doubleOnSubscribeDelayError() {
        TestHelper.checkDoubleOnSubscribeObservable(o -> o.concatMapDelayError(_ -> Observable.never()));
    }

    @Test
    public void scalarXMap() {
        Observable.fromCallable(() -> 1)
        .concatMap(_ -> Observable.just(2).hide())
        .test()
        .assertResult(2);
    }

    @Test
    public void rejectedFusion() {
        TestHelper.rejectObservableFusion()
        .concatMap(_  -> Observable.never())
        .test();
    }

    @Test
    public void rejectedFusionDelayError() {
        TestHelper.rejectObservableFusion()
        .concatMapDelayError(_  -> Observable.never())
        .test();
    }

    @Test
    public void asyncFusedDelayError() {
        UnicastSubject<Integer> uc = UnicastSubject.create();

        TestObserver<Integer> to = uc.concatMapDelayError(v -> Observable.just(v).hide())
        .test();

        uc.onNext(1);
        uc.onComplete();

        to.assertResult(1);
    }

    @Test
    public void scalarInnerJustDelayError() {
        Observable.just(1)
        .hide()
        .concatMapDelayError(v -> Observable.just(v))
        .test()
        .assertResult(1);
    }

    @Test
    public void scalarInnerEmptyDelayError() {
        Observable.just(1)
        .hide()
        .concatMapDelayError(_ -> Observable.empty())
        .test()
        .assertResult();
    }

    @Test
    public void scalarInnerJustDisposeDelayError() {
        TestObserver<Integer> to = new TestObserver<>();

        Observable.just(1)
        .hide()
        .concatMapDelayError(_ -> Observable.fromCallable(() -> {
            to.dispose();
            return 1;
        }))
        .subscribe(to);

        to.assertEmpty();
    }

    @Test
    public void scalarInnerEmptyDisposeDelayError() {
        TestObserver<Object> to = new TestObserver<>();

        Observable.just(1)
        .hide()
        .concatMapDelayError(_ -> new EmptyDisposingObservable(to))
        .subscribe(to);

        to.assertEmpty();
    }

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

        TestObserver<Integer> to = Observable.range(1, 5)
        .hide()
        .concatMapDelayError(_ -> ps)
        .test();

        ps.onComplete();

        to.assertResult();
    }
}
