/*
 * 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.AbstractCollection;

#if KEYS_PRIMITIVE
import java.util.Collection;
#endif

/** An abstract class providing basic methods for collections implementing a type-specific interface.
 *
 * <p>In particular, this class provide {@link #iterator()}, {@code add()}, {@link #remove(Object)} and
 * {@link #contains(Object)} methods that just call the type-specific counterpart.
 *
 * <p><strong>Warning</strong>: Because of a name clash between the list and collection interfaces
 * the type-specific deletion method of a type-specific abstract
 * collection is {@code rem()}, rather then {@code remove()}. A
 * subclass must thus override {@code rem()}, rather than
 * {@code remove()}, to make all inherited methods work properly.
 */

public abstract class ABSTRACT_COLLECTION KEY_GENERIC extends AbstractCollection<KEY_GENERIC_CLASS> implements COLLECTION KEY_GENERIC {

	protected ABSTRACT_COLLECTION() {}

	@Override
	public abstract KEY_ITERATOR KEY_GENERIC iterator();

#if KEYS_PRIMITIVE

	/** {@inheritDoc}
	 *
	 * @implSpec This implementation always throws an {@link UnsupportedOperationException}.
	 */
	@Override
	public boolean add(final KEY_TYPE k) {
		throw new UnsupportedOperationException();
	}

	/** {@inheritDoc}
	 *
	 * @implSpec This implementation iterates over the elements in the collection,
	 * looking for the specified element.
	 */
	@Override
	public boolean contains(final KEY_TYPE k) {
		final KEY_ITERATOR iterator = iterator();
		while (iterator.hasNext()) if (k == iterator.NEXT_KEY()) return true;
		return false;
	}

	/** {@inheritDoc}
	 *
	 * @implSpec This implementation iterates over the elements in the collection,
	 * looking for the specified element and tries to remove it.
	 */
	@Override
	public boolean rem(final KEY_TYPE k) {
		final KEY_ITERATOR KEY_GENERIC iterator = iterator();
		while (iterator.hasNext())
			if (k == iterator.NEXT_KEY()) {
				iterator.remove();
				return true;
			}
		return false;
	}

	/** {@inheritDoc}
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	public boolean add(final KEY_GENERIC_CLASS key) {
		return COLLECTION.super.add(key);
	}

	/** {@inheritDoc}
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	public boolean contains(final Object key) {
		return COLLECTION.super.contains(key);
	}

	/** {@inheritDoc}
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	public boolean remove(final Object key) {
		return COLLECTION.super.remove(key);
	}

	@Override
	public KEY_TYPE[] toArray(KEY_TYPE a[]) {
		final int size = size();
		if (a == null) {
			a = new KEY_TYPE[size];
		} else if (a.length < size) {
			a = java.util.Arrays.copyOf(a, size);
		}
		ITERATORS.unwrap(iterator(), a);
		return a;
	}

	@Override
	public KEY_TYPE[] TO_KEY_ARRAY() {
		return toArray((KEY_TYPE[]) null);
	}

	/** {@inheritDoc}
	 * @deprecated Please use {@code toArray()} instead&mdash;this method is redundant and will be removed in the future.
	 */
	@Deprecated
	@Override
	public KEY_TYPE[] TO_KEY_ARRAY(final KEY_TYPE a[]) {
		return toArray(a);
	}

#if KEYS_INT_LONG_DOUBLE
	/** {@inheritDoc}
	 *
	 * @apiNote This method exists to make final what should have been final in the interface.
	 */
	@Override
	public final void forEach(final KEY_CONSUMER action) {
		COLLECTION.super.forEach(action);
	}

	/** {@inheritDoc}
	 *
	 * @apiNote This method exists to make final what should have been final in the interface.
	 */
	@Override
	public final boolean removeIf(final KEY_PREDICATE filter) {
		return COLLECTION.super.removeIf(filter);
	}
#endif

	@Override
	public boolean addAll(final COLLECTION c) {
		boolean retVal = false;

		for(final KEY_ITERATOR i = c.iterator(); i.hasNext();)
			if (add(i.NEXT_KEY())) retVal = true;
		return retVal;
	}
	
	/** {@inheritDoc}
	 *
	 * @implSpec This implementation delegates to the type-specific version if given a type-specific
	 * collection, otherwise is uses the implementation from {@link AbstractCollection}.
	 */
	@Override
	public boolean addAll(final Collection<? extends KEY_CLASS> c) {
		if (c instanceof COLLECTION) {
			return addAll((COLLECTION) c);
		}
		return super.addAll(c);
	}

	@Override
	public boolean containsAll(final COLLECTION c) {
		for(final KEY_ITERATOR i = c.iterator(); i.hasNext();)
			if (! contains(i.NEXT_KEY())) return false;
		return true;
	}
	
	/** {@inheritDoc}
	 *
	 * @implSpec This implementation delegates to the type-specific version if given a type-specific
	 * collection, otherwise is uses the implementation from {@link AbstractCollection}.
	 */
	@Override
	public boolean containsAll(final Collection<?> c) {
		if (c instanceof COLLECTION) {
			return containsAll((COLLECTION) c);
		}
		return super.containsAll(c);
	}

	@Override
	public boolean removeAll(final COLLECTION c) {
		boolean retVal = false;
		for(final KEY_ITERATOR i = c.iterator(); i.hasNext();)
			if (rem(i.NEXT_KEY())) retVal = true;
		return retVal;
	}

	/** {@inheritDoc}
	 *
	 * @implSpec This implementation delegates to the type-specific version if given a type-specific
	 * collection, otherwise is uses the implementation from {@link AbstractCollection}.
	 */
	@Override
	public boolean removeAll(final Collection<?> c) {
		if (c instanceof COLLECTION) {
			return removeAll((COLLECTION) c);
		}
		return super.removeAll(c);
	}

	@Override
	public boolean retainAll(final COLLECTION c) {
		boolean retVal = false;
		for(final KEY_ITERATOR i = iterator(); i.hasNext();)
			if (! c.contains(i.NEXT_KEY())) {
				i.remove();
				retVal = true;
			}
		return retVal;
	}

	/** {@inheritDoc}
	 *
	 * @implSpec This implementation delegates to the type-specific version if given a type-specific
	 * collection, otherwise is uses the implementation from {@link AbstractCollection}.
	 */
	@Override
	public boolean retainAll(final Collection<?> c) {
		if (c instanceof COLLECTION) {
			return retainAll((COLLECTION) c);
		}
		return super.retainAll(c);
	}
#endif

	@Override
	public String toString() {
		final StringBuilder s = new StringBuilder();
		final KEY_ITERATOR KEY_GENERIC i = iterator();
		int n = size();
		KEY_TYPE k;
		boolean first = true;

		s.append("{");

		while(n-- != 0) {
			if (first) first = false;
			else s.append(", ");
			k = i.NEXT_KEY();
#if KEYS_REFERENCE
			if (this == k) s.append("(this collection)"); else
#endif
				s.append(String.valueOf(k));
		}

		s.append("}");
		return s.toString();
	}
}
