/*
 * Copyright 2014 (C) Tom Parker <thpr@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
 */
package pcgen.cdom.content.factset;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import pcgen.base.util.Indirect;
import pcgen.base.util.ObjectContainer;
import pcgen.cdom.base.CDOMObject;
import pcgen.rules.context.AbstractReferenceContext;
import pcgen.rules.context.LoadContext;

/**
 * A FactSetGroup is an ObjectContainer that contains objects of a specific type
 * (e.g. Skill) that contain a specific value in a given FACTSET
 * 
 * @param <T>
 *            The Type of object contained in this FactSetGroup
 * @param <F>
 *            The Type of the FactSet being checked in this FactSetGroup
 */
public class FactSetGroup<T extends CDOMObject, F> implements
		ObjectContainer<T>
{

	/**
	 * Contains the underlying FactSetInfo for this FactSetGroup (identifying
	 * the "rules of the road")
	 */
	private final FactSetInfo<T, F> def;

	/**
	 * The Indirect containing the fact to be matched
	 */
	private final Indirect<F> toMatch;

	/**
	 * The ObjectContainer containing all of the objects of the type of object
	 * where this FactSetGroup (and thus the FactInfo) are usable
	 */
	private final ObjectContainer<T> allObjects;

	/**
	 * The cached answers for this FactSetGroup.
	 * 
	 * Note that this cache can exist because these items are facts, and thus
	 * semantically can't change. There is also the assumption that the global
	 * list of objects cannot change.
	 */
	private List<T> cache;

	/**
	 * Constructs a new FactSetGroup from the given context, FactSetInfo and
	 * value.
	 * 
	 * @param context
	 *            The LoadContext used to resolve references
	 * @param fsi
	 *            The FactSetInfo indicating the underlying characteristics of
	 *            the Fact that this FactSetGroup will check
	 * @param value
	 *            The String representation of the value that this FactSetGroup
	 *            will be looking for
	 */
	public FactSetGroup(LoadContext context, FactSetInfo<T, F> fsi, String value)
	{
		if (fsi.getUsableLocation().equals(CDOMObject.class))
		{
			throw new IllegalArgumentException("FactSetGroup cannot be global");
		}
		def = fsi;
		AbstractReferenceContext refContext = context.getReferenceContext();
		allObjects = refContext.getCDOMAllReference(def.getUsableLocation());
		toMatch = def.getFormatManager().convertIndirect(value);
		if (toMatch == null)
		{
			throw new IllegalArgumentException("Failed to convert " + value
				+ " as a "
				+ def.getFormatManager().getManagedClass().getSimpleName());
		}
	}

	/**
	 * @see pcgen.base.util.ObjectContainer#getContainedObjects()
	 */
	@Override
	public Collection<T> getContainedObjects()
	{
		if (cache == null)
		{
			List<T> setupCache = new ArrayList<>();
			for (T obj : allObjects.getContainedObjects())
			{
				if (contains(obj))
				{
					setupCache.add(obj);
				}
			}
			cache = setupCache;
		}
		return Collections.unmodifiableCollection(cache);
	}

	/**
	 * @see pcgen.base.util.ObjectContainer#getLSTformat(boolean)
	 */
	@Override
	public String getLSTformat(boolean useAny)
	{
		return def.getFactSetName() + "="
			+ def.getFormatManager().unconvert(toMatch.get());
	}

	/**
	 * @see pcgen.base.util.ObjectContainer#contains(java.lang.Object)
	 */
	@Override
	public boolean contains(T obj)
	{
		List<Indirect<F>> factset = obj.getSetFor(def.getFactSetKey());
		if (factset != null)
		{
			F tgt = toMatch.get();
			for (Indirect<F> indirect : factset)
			{
				if (indirect.get().equals(tgt))
				{
					return true;
				}
			}
		}
		return false;
	}

	/**
	 * @see pcgen.base.util.ObjectContainer#getReferenceClass()
	 */
	@Override
	public Class<T> getReferenceClass()
	{
		return allObjects.getReferenceClass();
	}
}