/*
 * Copyright (c) 2008 Tom Parker <thpr@users.sourceforge.net>
 * 
 * This program 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 program 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */
package pcgen.cdom.helper;

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

import pcgen.cdom.reference.CDOMSingleRef;
import pcgen.core.EquipmentModifier;

/**
 * An EqModRef represents a reference to a Specific EquipmentModifier with set
 * choices.
 * 
 * This is typically used for tokens where an EquipmentModifier is directly
 * granted, or a selection of only a specific choice for an EquipmentModifier is
 * allowed.
 */
public class EqModRef
{

	/**
	 * A reference to the EquipmentModifier which this EqModRef contains
	 */
	private final CDOMSingleRef<EquipmentModifier> eqMod;

	/**
	 * The specific choices (associations) for the EquipmentModifier this
	 * EqModRef contains. May remain null if the given EquipmentModifier does
	 * not have a specific choice (or does not require a specific choice)
	 */
	private List<String> choices = null;

	/**
	 * Constructs a new EqModRef for the EquipmentModifier in the given
	 * reference.
	 * 
	 * @param modRef
	 *            A reference to the EquipmentModifier which this EqModRef
	 *            contains
	 */
	public EqModRef(CDOMSingleRef<EquipmentModifier> modRef)
	{
		eqMod = modRef;
	}

	/**
	 * Adds the specific choice (association) for the EquipmentModifier this
	 * EqModRef contains.
	 * 
	 * @param choice
	 *            The specific choice (association) that should be added for the
	 *            EquipmentModifier this EqModRef contains.
	 */
	public void addChoice(String choice)
	{
		if (choices == null)
		{
			choices = new LinkedList<>();
		}
		choices.add(choice);
	}

	/**
	 * Returns the reference to the EquipmentModifier that this EqModRef
	 * contains
	 * 
	 * @return The reference to the EquipmentModifier that this EqModRef
	 *         contains
	 */
	public CDOMSingleRef<EquipmentModifier> getRef()
	{
		return eqMod;
	}

	/**
	 * Returns the specific choices (associations) for the EquipmentModifier
	 * this EqModRef contains.
	 * 
	 * This method is value-semantic in that ownership of the returned List is
	 * transferred to the class calling this method. Modification of the
	 * returned List will not modify this EqModRef and modification of this
	 * EqModRef will not modify the returned List.
	 * 
	 * This method will not return null, even if addChoice was never called on
	 * this EqModRef.
	 * 
	 * @return The specific choices (associations) for the EquipmentModifier
	 *         this EqModRef contains.
	 */
	public List<String> getChoices()
	{
		return (choices == null ? Collections.emptyList()
				: new ArrayList<>(choices));
	}

	/**
	 * Returns true if the given object is a EqModRef with identical underlying
	 * EquipmentModifier reference and choices.
	 * 
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	@Override
	public boolean equals(Object obj)
	{
		if (obj instanceof EqModRef)
		{
			EqModRef other = (EqModRef) obj;
			if (other.eqMod.equals(eqMod))
			{
				if (choices == null)
				{
					return other.choices == null;
				}
				else
				{
					return choices.equals(other.choices);
				}
			}
		}
		return false;
	}

	/**
	 * Returns a consistent-with-equals hashCode for this EqModRef
	 * 
	 * @see java.lang.Object#hashCode()
	 */
	@Override
	public int hashCode()
	{
		return 3 - eqMod.hashCode();
	}

}