Copyright (c) 2016-present, RxJava Contributors.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is
distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
the License for the specific language governing permissions and limitations under the License.
/**
 * Copyright (c) 2016-present, RxJava Contributors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
 * the License for the specific language governing permissions and limitations under the License.
 */
package io.reactivex.internal.operators.flowable;

import java.util.List;
import java.util.concurrent.*;

import org.reactivestreams.*;

import io.reactivex.*;
import io.reactivex.flowables.ConnectableFlowable;
import io.reactivex.functions.*;
import io.reactivex.internal.functions.*;

Helper utility class to support Flowable with inner classes.
/**
 * Helper utility class to support Flowable with inner classes.
 */
public final class FlowableInternalHelper {

    
Utility class. /** Utility class. */
    private FlowableInternalHelper() {
        throw new IllegalStateException("No instances!");
    }

    static final class SimpleGenerator<T, S> implements BiFunction<S, Emitter<T>, S> {
        final Consumer<Emitter<T>> consumer;

        SimpleGenerator(Consumer<Emitter<T>> consumer) {
            this.consumer = consumer;
        }

        @Override
        public S apply(S t1, Emitter<T> t2) throws Exception {
            consumer.accept(t2);
            return t1;
        }
    }

    public static <T, S> BiFunction<S, Emitter<T>, S> simpleGenerator(Consumer<Emitter<T>> consumer) {
        return new SimpleGenerator<T, S>(consumer);
    }

    static final class SimpleBiGenerator<T, S> implements BiFunction<S, Emitter<T>, S> {
        final BiConsumer<S, Emitter<T>> consumer;

        SimpleBiGenerator(BiConsumer<S, Emitter<T>> consumer) {
            this.consumer = consumer;
        }

        @Override
        public S apply(S t1, Emitter<T> t2) throws Exception {
            consumer.accept(t1, t2);
            return t1;
        }
    }

    public static <T, S> BiFunction<S, Emitter<T>, S> simpleBiGenerator(BiConsumer<S, Emitter<T>> consumer) {
        return new SimpleBiGenerator<T, S>(consumer);
    }

    static final class ItemDelayFunction<T, U> implements Function<T, Publisher<T>> {
        final Function<? super T, ? extends Publisher<U>> itemDelay;

        ItemDelayFunction(Function<? super T, ? extends Publisher<U>> itemDelay) {
            this.itemDelay = itemDelay;
        }

        @Override
        public Publisher<T> apply(final T v) throws Exception {
            Publisher<U> p = ObjectHelper.requireNonNull(itemDelay.apply(v), "The itemDelay returned a null Publisher");
            return new FlowableTakePublisher<U>(p, 1).map(Functions.justFunction(v)).defaultIfEmpty(v);
        }
    }

    public static <T, U> Function<T, Publisher<T>> itemDelay(final Function<? super T, ? extends Publisher<U>> itemDelay) {
        return new ItemDelayFunction<T, U>(itemDelay);
    }

    static final class SubscriberOnNext<T> implements Consumer<T> {
        final Subscriber<T> subscriber;

        SubscriberOnNext(Subscriber<T> subscriber) {
            this.subscriber = subscriber;
        }

        @Override
        public void accept(T v) throws Exception {
            subscriber.onNext(v);
        }
    }

    static final class SubscriberOnError<T> implements Consumer<Throwable> {
        final Subscriber<T> subscriber;

        SubscriberOnError(Subscriber<T> subscriber) {
            this.subscriber = subscriber;
        }

        @Override
        public void accept(Throwable v) throws Exception {
            subscriber.onError(v);
        }
    }

    static final class SubscriberOnComplete<T> implements Action {
        final Subscriber<T> subscriber;

        SubscriberOnComplete(Subscriber<T> subscriber) {
            this.subscriber = subscriber;
        }

        @Override
        public void run() throws Exception {
            subscriber.onComplete();
        }
    }

    public static <T> Consumer<T> subscriberOnNext(Subscriber<T> subscriber) {
        return new SubscriberOnNext<T>(subscriber);
    }

    public static <T> Consumer<Throwable> subscriberOnError(Subscriber<T> subscriber) {
        return new SubscriberOnError<T>(subscriber);
    }

    public static <T> Action subscriberOnComplete(Subscriber<T> subscriber) {
        return new SubscriberOnComplete<T>(subscriber);
    }

    static final class FlatMapWithCombinerInner<U, R, T> implements Function<U, R> {
        private final BiFunction<? super T, ? super U, ? extends R> combiner;
        private final T t;

        FlatMapWithCombinerInner(BiFunction<? super T, ? super U, ? extends R> combiner, T t) {
            this.combiner = combiner;
            this.t = t;
        }

        @Override
        public R apply(U w) throws Exception {
            return combiner.apply(t, w);
        }
    }

    static final class FlatMapWithCombinerOuter<T, R, U> implements Function<T, Publisher<R>> {
        private final BiFunction<? super T, ? super U, ? extends R> combiner;
        private final Function<? super T, ? extends Publisher<? extends U>> mapper;

        FlatMapWithCombinerOuter(BiFunction<? super T, ? super U, ? extends R> combiner,
                Function<? super T, ? extends Publisher<? extends U>> mapper) {
            this.combiner = combiner;
            this.mapper = mapper;
        }

        @Override
        public Publisher<R> apply(final T t) throws Exception {
            @SuppressWarnings("unchecked")
            Publisher<U> u = (Publisher<U>)ObjectHelper.requireNonNull(mapper.apply(t), "The mapper returned a null Publisher");
            return new FlowableMapPublisher<U, R>(u, new FlatMapWithCombinerInner<U, R, T>(combiner, t));
        }
    }

    public static <T, U, R> Function<T, Publisher<R>> flatMapWithCombiner(
            final Function<? super T, ? extends Publisher<? extends U>> mapper,
                    final BiFunction<? super T, ? super U, ? extends R> combiner) {
        return new FlatMapWithCombinerOuter<T, R, U>(combiner, mapper);
    }

    static final class FlatMapIntoIterable<T, U> implements Function<T, Publisher<U>> {
        private final Function<? super T, ? extends Iterable<? extends U>> mapper;

        FlatMapIntoIterable(Function<? super T, ? extends Iterable<? extends U>> mapper) {
            this.mapper = mapper;
        }

        @Override
        public Publisher<U> apply(T t) throws Exception {
            return new FlowableFromIterable<U>(ObjectHelper.requireNonNull(mapper.apply(t), "The mapper returned a null Iterable"));
        }
    }

    public static <T, U> Function<T, Publisher<U>> flatMapIntoIterable(final Function<? super T, ? extends Iterable<? extends U>> mapper) {
        return new FlatMapIntoIterable<T, U>(mapper);
    }

    public static <T> Callable<ConnectableFlowable<T>> replayCallable(final Flowable<T> parent) {
        return new ReplayCallable<T>(parent);
    }

    public static <T> Callable<ConnectableFlowable<T>> replayCallable(final Flowable<T> parent, final int bufferSize) {
        return new BufferedReplayCallable<T>(parent, bufferSize);
    }

    public static <T> Callable<ConnectableFlowable<T>> replayCallable(final Flowable<T> parent, final int bufferSize, final long time, final TimeUnit unit, final Scheduler scheduler) {
        return new BufferedTimedReplay<T>(parent, bufferSize, time, unit, scheduler);
    }

    public static <T> Callable<ConnectableFlowable<T>> replayCallable(final Flowable<T> parent, final long time, final TimeUnit unit, final Scheduler scheduler) {
        return new TimedReplay<T>(parent, time, unit, scheduler);
    }

    public static <T, R> Function<Flowable<T>, Publisher<R>> replayFunction(final Function<? super Flowable<T>, ? extends Publisher<R>> selector, final Scheduler scheduler) {
        return new ReplayFunction<T, R>(selector, scheduler);
    }

    public enum RequestMax implements Consumer<Subscription> {
        INSTANCE;
        @Override
        public void accept(Subscription t) throws Exception {
            t.request(Long.MAX_VALUE);
        }
    }

    static final class ZipIterableFunction<T, R>
    implements Function<List<Publisher<? extends T>>, Publisher<? extends R>> {
        private final Function<? super Object[], ? extends R> zipper;

        ZipIterableFunction(Function<? super Object[], ? extends R> zipper) {
            this.zipper = zipper;
        }

        @Override
        public Publisher<? extends R> apply(List<Publisher<? extends T>> list) {
            return Flowable.zipIterable(list, zipper, false, Flowable.bufferSize());
        }
    }

    public static <T, R> Function<List<Publisher<? extends T>>, Publisher<? extends R>> zipIterable(final Function<? super Object[], ? extends R> zipper) {
        return new ZipIterableFunction<T, R>(zipper);
    }

    static final class ReplayCallable<T> implements Callable<ConnectableFlowable<T>> {
        private final Flowable<T> parent;

        ReplayCallable(Flowable<T> parent) {
            this.parent = parent;
        }

        @Override
        public ConnectableFlowable<T> call() {
            return parent.replay();
        }
    }

    static final class BufferedReplayCallable<T> implements Callable<ConnectableFlowable<T>> {
        private final Flowable<T> parent;
        private final int bufferSize;

        BufferedReplayCallable(Flowable<T> parent, int bufferSize) {
            this.parent = parent;
            this.bufferSize = bufferSize;
        }

        @Override
        public ConnectableFlowable<T> call() {
            return parent.replay(bufferSize);
        }
    }

    static final class BufferedTimedReplay<T> implements Callable<ConnectableFlowable<T>> {
        private final Flowable<T> parent;
        private final int bufferSize;
        private final long time;
        private final TimeUnit unit;
        private final Scheduler scheduler;

        BufferedTimedReplay(Flowable<T> parent, int bufferSize, long time, TimeUnit unit, Scheduler scheduler) {
            this.parent = parent;
            this.bufferSize = bufferSize;
            this.time = time;
            this.unit = unit;
            this.scheduler = scheduler;
        }

        @Override
        public ConnectableFlowable<T> call() {
            return parent.replay(bufferSize, time, unit, scheduler);
        }
    }

    static final class TimedReplay<T> implements Callable<ConnectableFlowable<T>> {
        private final Flowable<T> parent;
        private final long time;
        private final TimeUnit unit;
        private final Scheduler scheduler;

        TimedReplay(Flowable<T> parent, long time, TimeUnit unit, Scheduler scheduler) {
            this.parent = parent;
            this.time = time;
            this.unit = unit;
            this.scheduler = scheduler;
        }

        @Override
        public ConnectableFlowable<T> call() {
            return parent.replay(time, unit, scheduler);
        }
    }

    static final class ReplayFunction<T, R> implements Function<Flowable<T>, Publisher<R>> {
        private final Function<? super Flowable<T>, ? extends Publisher<R>> selector;
        private final Scheduler scheduler;

        ReplayFunction(Function<? super Flowable<T>, ? extends Publisher<R>> selector, Scheduler scheduler) {
            this.selector = selector;
            this.scheduler = scheduler;
        }

        @Override
        public Publisher<R> apply(Flowable<T> t) throws Exception {
            Publisher<R> p = ObjectHelper.requireNonNull(selector.apply(t), "The selector returned a null Publisher");
            return Flowable.fromPublisher(p).observeOn(scheduler);
        }
    }
}