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/*
 * Copyright (c) 2007, intarsys consulting GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * - Neither the name of intarsys nor the names of its contributors may be used
 *   to endorse or promote products derived from this software without specific
 *   prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package de.intarsys.pdf.pd;

import java.util.ArrayList;
import java.util.List;

import de.intarsys.pdf.cos.COSBasedObject;
import de.intarsys.pdf.cos.COSDictionary;
import de.intarsys.pdf.cos.COSName;
import de.intarsys.pdf.cos.COSObject;

/**
 * Factoring out the commonalities between the PDOutline and PDOutlineItem.
 */
public abstract class PDOutlineNode extends PDObject {
	/**
	 * The meta class implementation
	 */
	public static class MetaClass extends PDObject.MetaClass {
		protected MetaClass(Class instanceClass) {
			super(instanceClass);
		}

		@Override
		protected COSBasedObject.MetaClass doDetermineClass(COSObject object) {
			if (object instanceof COSDictionary) {
				COSDictionary dict = (COSDictionary) object;
				COSName type = dict.get(PDObject.DK_Type).asName();
				if (PDOutline.CN_Type_Outlines.equals(type)) {
					return PDOutline.META;
				}
				if (dict.get(PDOutlineItem.DK_Parent).isNull()
						&& dict.get(PDOutlineItem.DK_Title).isNull()) {
					return PDOutline.META;
				}
				return PDOutlineItem.META;
			}
			return super.doDetermineClass(object);
		}

		@Override
		public Class getRootClass() {
			return PDOutlineNode.class;
		}
	}

	/** The meta class instance */
	public static final MetaClass META = new MetaClass(MetaClass.class
			.getDeclaringClass());

	public static final COSName DK_First = COSName.constant("First");

	public static final COSName DK_Last = COSName.constant("Last");

	public static final COSName DK_Count = COSName.constant("Count");

	protected PDOutlineNode(COSObject object) {
		super(object);
	}

	/**
	 * Add a new {@link PDOutlineItem}.
	 * 
	 * @param newItem
	 *            The new item to be inserted at the end.
	 */
	public void addItem(PDOutlineItem newItem) {
		changeCount(1);
		PDOutlineItem first = getFirst();
		if (first == null) {
			setFirst(newItem);
		}
		PDOutlineItem last = getLast();
		if (last != null) {
			last.setNext(newItem);
			newItem.setPrev(last);
		}
		setLast(newItem);
		newItem.setParent(this);
	}

	protected void changeCount(int value) {
		int newCount = getCount();
		if (newCount < 0) {
			newCount -= value;
		} else {
			newCount += value;
		}
		setCount(newCount);
		if (getParent() != null) {
			getParent().changeCount(value);
		}
	}

	/**
	 * Collapse this node (mark the children invisible).
	 * 
	 * @return true  if the expansion state of the node changes.
	 */
	public boolean collapse() {
		if (getCount() <= 0) {
			return false;
		}
		setCount(-getCount());
		if (getParent() != null) {
			getParent().changeCount(getCount());
		}
		return true;
	}

	/**
	 * Expand this node (mark the children visible).
	 * 
	 * @return true  if the expansion state of the node changes.
	 */
	public boolean expand() {
		if (getCount() >= 0) {
			return false;
		}
		setCount(-getCount());
		if (getParent() != null) {
			getParent().changeCount(getCount());
		}
		return true;
	}

	/**
	 * The list of all child nodes for this.
	 * 
	 * @return The list of all child nodes for this.
	 */
	public List getChildren() {
		List result = new ArrayList();
		PDOutlineItem current = getFirst();
		while (current != null) {
			result.add(current);
			current = current.getNext();
		}
		return result;
	}

	/**
	 * The number of child elements.
	 * 
	 * @return The number of child elements.
	 */
	public int getCount() {
		return getFieldInt(DK_Count, 0);
	}

	/**
	 * The first child element in the linked list of children.
	 * 
	 * @return The first child element in the linked list of children.
	 */
	public PDOutlineItem getFirst() {
		return (PDOutlineItem) PDOutlineItem.META
				.createFromCos(cosGetField(DK_First));
	}

	/**
	 * The last child element in the linked list of children.
	 * 
	 * @return The last child element in the linked list of children.
	 */
	public PDOutlineItem getLast() {
		return (PDOutlineItem) PDOutlineItem.META
				.createFromCos(cosGetField(DK_Last));
	}

	protected PDOutlineNode getParent() {
		return null;
	}

	/**
	 * true if this is the outline (root element) itself.
	 * 
	 * @return true if this is the outline (root element) itself.
	 */
	public boolean isOutline() {
		return false;
	}

	/**
	 * Remove a {@link PDOutlineItem} from this.
	 * 
	 * @param pItem
	 *            The item to be removed.
	 * @return true if the item was removed.
	 */
	public boolean removeItem(PDOutlineItem pItem) {
		if (pItem.getParent() != this) {
			return false;
		}
		changeCount(-1);
		if (pItem.getPrev() != null) {
			pItem.getPrev().setNext(pItem.getNext());
		}
		if (pItem.getNext() != null) {
			pItem.getNext().setPrev(pItem.getPrev());
		}
		if (getFirst() == pItem) {
			setFirst(pItem.getNext());
		}
		if (getLast() == pItem) {
			setLast(pItem.getPrev());
		}
		pItem.setParent(null);
		return true;
	}

	protected void setCount(int newCount) {
		setFieldInt(DK_Count, newCount);
	}

	protected void setFirst(PDOutlineItem first) {
		setFieldObject(DK_First, first);
	}

	protected void setLast(PDOutlineItem last) {
		setFieldObject(DK_Last, last);
	}
}