/*
 * SortedListFacade.java
 * Copyright 2010 Connor Petty <cpmeister@users.sourceforge.net>
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 * 
 * Created on May 6, 2010, 3:12:25 PM
 */
package pcgen.facade.util;

import java.util.Arrays;
import java.util.Comparator;

import org.apache.commons.lang3.ArrayUtils;

import pcgen.facade.util.event.ListEvent;
import pcgen.facade.util.event.ListListener;
import pcgen.util.Logging;

/**
 *
 * @author Connor Petty <cpmeister@users.sourceforge.net>
 */
public class SortedListFacade<E> extends AbstractListFacade<E> implements ListListener<E>
{

	private ListFacade<E> delegate = null;
	private Comparator<? super E> comparator;
	private Comparator<Integer> indexComparator = new Comparator<Integer>()
	{

        @Override
		public int compare(Integer o1, Integer o2)
		{
			E e1 = delegate.getElementAt(o1);
			E e2 = delegate.getElementAt(o2);
			return comparator.compare(e1, e2);
		}

	};

	public SortedListFacade(Comparator<? super E> comparator)
	{
		this.comparator = comparator;
	}

	public SortedListFacade(Comparator<? super E> comparator, ListFacade<E> list)
	{
		this.comparator = comparator;
		setDelegate(list);
	}

	private Integer[] transform = null;

    @Override
	public int getSize()
	{
		return delegate.getSize();
	}

    @Override
	public E getElementAt(int index)
	{
		return delegate.getElementAt(transform[index]);
	}

	public void setDelegate(ListFacade<E> list)
	{
		ListFacade<E> oldList = this.delegate;
		if (oldList != null)
		{
			oldList.removeListListener(this);
		}
		this.delegate = list;
		if (list != null)
		{
			list.addListListener(this);
		}
		elementsChanged(null);
	}

	public void setComparator(Comparator<? super E> comparator)
	{
		this.comparator = comparator;
		elementsChanged(null);
	}

    @Override
	public void elementAdded(ListEvent<E> e)
	{
		transform = (Integer[]) ArrayUtils.add(transform, transform.length);
		sanityCheck();
		Arrays.sort(transform, indexComparator);
		int index = Arrays.binarySearch(transform, e.getIndex(), indexComparator);
		fireElementAdded(this, e.getElement(), index);
	}

    @Override
	public void elementRemoved(ListEvent<E> e)
	{
		int index = ArrayUtils.indexOf(transform, e.getIndex());
		transform = (Integer[]) ArrayUtils.removeElement(transform, transform.length - 1);
		sanityCheck();
		Arrays.sort(transform, indexComparator);
		fireElementRemoved(this, e.getElement(), index);
	}

    @Override
	public void elementsChanged(ListEvent<E> e)
	{
		transform = new Integer[delegate.getSize()];
		for (int i = 0; i < transform.length; i++)
		{
			transform[i] = i;
		}
		sanityCheck();
		Arrays.sort(transform, indexComparator);
		fireElementsChanged(this);
	}

	@Override
	public void elementModified(ListEvent<E> e)
	{
		sanityCheck();
		int index = Arrays.binarySearch(transform, e.getIndex(), indexComparator);
		fireElementModified(this, e.getElement(), index);
	}

	private boolean sanityCheck()
	{
		if (delegate.getSize() != transform.length)
		{ 
			String msg =
					String
						.format(
							"Mismatched sizes between sorted facade %d and base list %d. "
								+ "Delegate is %s. Transform is %s.",
							transform.length, delegate.getSize(), delegate, transform);
			Logging.errorPrint(msg, new Throwable());
			return false;
		}
		return true;
	}
}