Copyright (c), Data Geekery GmbH, contact@datageekery.com
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), Data Geekery GmbH, contact@datageekery.com
 *
 * 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 org.jooq.lambda;

import static java.util.Comparator.comparing;
import static org.jooq.lambda.Seq.seq;

import java.util.*;
import java.util.function.Consumer;
import java.util.function.Predicate;
import java.util.stream.Collector;
import java.util.stream.Stream;

import org.jooq.lambda.tuple.Tuple2;

Author:
Lukas Eder/**
 * @author Lukas Eder
 */
class SeqUtils {

    @SafeVarargs
    @SuppressWarnings("unchecked")
    static <T> Seq<T>[] seqs(Stream<? extends T>... streams) {
        if (streams == null)
            return null;

        return Seq.of(streams).map(Seq::seq).toArray(Seq[]::new);
    }

    @SafeVarargs
    @SuppressWarnings("unchecked")
    static <T> Seq<T>[] seqs(Iterable<? extends T>... iterables) {
        if (iterables == null)
            return null;

        return Seq.of(iterables).map(Seq::seq).toArray(Seq[]::new);
    }

    static <T, U> Seq<U> transform(Stream<? extends T> stream, DelegatingSpliterator<T, U> delegating) {
        Spliterator<? extends T> delegate = stream.spliterator();

        return Seq.seq(new Spliterator<U>() {
            @Override
            public boolean tryAdvance(Consumer<? super U> action) {
                return delegating.tryAdvance(delegate, action);
            }

            @Override
            public Spliterator<U> trySplit() {
                return null;
            }

            @Override
            public long estimateSize() {
                return Long.MAX_VALUE;
            }

            @Override
            public int characteristics() {
                return delegate.characteristics() & Spliterator.ORDERED;
            }
            
            @Override
            @SuppressWarnings("unchecked")
            public Comparator<? super U> getComparator() {
                
                // This implementation works with the JDK 8, as the information
                // is really only used in 
                // java.util.stream.StreamOpFlag.fromCharacteristics(Spliterator<?> spliterator)
                // Currently, the point of this method is only to be used for
                // optimisations (e.g. to avoid sorting a stream twice in a row)
                return (Comparator) delegate.getComparator();
            }
        }).onClose(() -> stream.close());
    }
    
    static <T> Map<?, Partition<T>> partitions(WindowSpecification<T> window, List<Tuple2<T, Long>> input) {
        return seq(input).groupBy(
            window.partition().compose(t -> t.v1), 
            Collector.<
                Tuple2<T, Long>,
                Collection<Tuple2<T, Long>>,
                Partition<T>
            >of(
                () -> window.order().isPresent()
                    ? new TreeSet<>(comparing((Tuple2<T, Long> t) -> t.v1, window.order().get()).thenComparing(t -> t.v2))
                    : new ArrayList<>(),
                (s, t) -> s.add(t),
                (s1, s2) -> { s1.addAll(s2); return s1; },
                Partition::new
            )
        );
    }

    static <T> OptionalLong indexOf(Iterator<T> iterator, Predicate<? super T> predicate) {
        for (long index = 0; iterator.hasNext(); index++)
            if (predicate.test(iterator.next()))
                return OptionalLong.of(index);

        return OptionalLong.empty();
    }
    
    
Sneaky throw any type of Throwable.
/**
     * Sneaky throw any type of Throwable.
     */
    static void sneakyThrow(Throwable throwable) {
        SeqUtils.<RuntimeException>sneakyThrow0(throwable);
    }

    
Sneaky throw any type of Throwable.
/**
     * Sneaky throw any type of Throwable.
     */
    @SuppressWarnings("unchecked")
    static <E extends Throwable> void sneakyThrow0(Throwable throwable) throws E {
        throw (E) throwable;
    }

    @FunctionalInterface
    interface DelegatingSpliterator<T, U> {
        boolean tryAdvance(Spliterator<? extends T> delegate, Consumer<? super U> action);
    }
    
    static Runnable closeAll(AutoCloseable... closeables) {
        return () -> {
            Throwable t = null;
            
            for (AutoCloseable closeable : closeables) {
                try {
                    closeable.close();
                }
                catch (Throwable t1) {
                    if (t == null)
                        t = t1;
                    else
                        t.addSuppressed(t1);
                }
            }
            
            if (t != null)
                sneakyThrow(t);
        };
    }
}