/*
 * Copyright (C) 2002-2022 Sebastiano Vigna
 *
 * 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 PACKAGE;

import java.util.Comparator;

/** A type-specific {@link Comparator}; provides methods to compare two primitive types both as objects
 * and as primitive types.
 *
 * <p>Note that {@code fastutil} provides a corresponding abstract class that
 * can be used to implement this interface just by specifying the type-specific
 * comparator.
 *
 * @see Comparator
 */

@FunctionalInterface
public interface KEY_COMPARATOR KEY_GENERIC extends Comparator<KEY_GENERIC_CLASS> {

	/** Compares its two primitive-type arguments for order. Returns a negative integer,
	 * zero, or a positive integer as the first argument is less than, equal
	 * to, or greater than the second.
	 *
	 * @see java.util.Comparator
	 * @return a negative integer, zero, or a positive integer as the first
	 * argument is less than, equal to, or greater than the second.
	 */

	int compare(KEY_TYPE k1, KEY_TYPE k2);

	@Override
	default KEY_COMPARATOR KEY_GENERIC reversed() {
		return COMPARATORS.oppositeComparator(this);
	}

#if KEYS_PRIMITIVE
	/** {@inheritDoc}
	 * @implSpec This implementation delegates to the corresponding type-specific method.
	 * @deprecated Please use the corresponding type-specific method instead. */
	@Deprecated
	@Override
	default int compare(KEY_GENERIC_CLASS ok1, KEY_GENERIC_CLASS ok2) {
		return compare(ok1.KEY_VALUE(), ok2.KEY_VALUE());
	}

	/** Return a new comparator that first uses this comparator, then uses the second comparator
	 * if this comparator compared the two elements as equal.
	 *
	 * @see Comparator#thenComparing(Comparator)
	 */
	default KEY_COMPARATOR KEY_GENERIC thenComparing(KEY_COMPARATOR KEY_SUPER_GENERIC second) {
		return (KEY_COMPARATOR KEY_SUPER_GENERIC & java.io.Serializable) (k1, k2) -> {
			int comp = compare(k1, k2);
			return comp == 0 ? second.compare(k1, k2) : comp;
		};
	}

	@Override
	default Comparator<KEY_GENERIC_CLASS> KEY_GENERIC thenComparing(Comparator<? super KEY_GENERIC_CLASS> second) {
		if (second instanceof KEY_COMPARATOR) return thenComparing((KEY_COMPARATOR KEY_SUPER_GENERIC)second);
		return Comparator.super.thenComparing(second);
	}
#endif
}
