/**
 * 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.observable;

import io.reactivex.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.exceptions.Exceptions;
import io.reactivex.functions.Predicate;
import io.reactivex.internal.disposables.DisposableHelper;
import io.reactivex.internal.fuseable.FuseToObservable;
import io.reactivex.plugins.RxJavaPlugins;

public final class ObservableAnySingle<T> extends Single<Boolean> implements FuseToObservable<Boolean> {
    final ObservableSource<T> source;

    final Predicate<? super T> predicate;

    public ObservableAnySingle(ObservableSource<T> source, Predicate<? super T> predicate) {
        this.source = source;
        this.predicate = predicate;
    }

    @Override
    protected void subscribeActual(SingleObserver<? super Boolean> t) {
        source.subscribe(new AnyObserver<T>(t, predicate));
    }

    @Override
    public Observable<Boolean> fuseToObservable() {
        return RxJavaPlugins.onAssembly(new ObservableAny<T>(source, predicate));
    }

    static final class AnyObserver<T> implements Observer<T>, Disposable {

        final SingleObserver<? super Boolean> actual;
        final Predicate<? super T> predicate;

        Disposable s;

        boolean done;

        AnyObserver(SingleObserver<? super Boolean> actual, Predicate<? super T> predicate) {
            this.actual = actual;
            this.predicate = predicate;
        }
        @Override
        public void onSubscribe(Disposable s) {
            if (DisposableHelper.validate(this.s, s)) {
                this.s = s;
                actual.onSubscribe(this);
            }
        }

        @Override
        public void onNext(T t) {
            if (done) {
                return;
            }
            boolean b;
            try {
                b = predicate.test(t);
            } catch (Throwable e) {
                Exceptions.throwIfFatal(e);
                s.dispose();
                onError(e);
                return;
            }
            if (b) {
                done = true;
                s.dispose();
                actual.onSuccess(true);
            }
        }

        @Override
        public void onError(Throwable t) {
            if (done) {
                RxJavaPlugins.onError(t);
                return;
            }

            done = true;
            actual.onError(t);
        }

        @Override
        public void onComplete() {
            if (!done) {
                done = true;
                actual.onSuccess(false);
            }
        }

        @Override
        public void dispose() {
            s.dispose();
        }

        @Override
        public boolean isDisposed() {
            return s.isDisposed();
        }
    }
}
