/*******************************************************************************
 * Copyright (c) 2001, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Jens Lukowski/Innoopract - initial renaming/restructuring
 *     
 *******************************************************************************/
package org.eclipse.wst.xml.core.internal.document;


import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.Text;

/**
 * XMLModelContext class
 */
class XMLModelContext {
	private Node nextNode = null;
	private Node parentNode = null;

	//	private XMLModelImpl model = null;
	private Node rootNode = null;

	/**
	 * XMLModelContext constructor
	 * 
	 * @param rootNode
	 *            org.w3c.dom.Node
	 */
	XMLModelContext(Node rootNode) {
		super();

		this.rootNode = rootNode;
	}

	/**
	 * findEndTag method
	 * 
	 * @return org.w3c.dom.Element
	 * @param tagName
	 *            java.lang.String
	 */
	Element findEndTag(String tagName) {
		if (tagName == null)
			return null;
		if (this.parentNode == null)
			return null;

		for (Node parent = this.parentNode.getParentNode(); parent != null; parent = parent.getParentNode()) {
			if (parent.getNodeType() != Node.ELEMENT_NODE)
				break;
			ElementImpl element = (ElementImpl) parent;
			if (element.hasEndTag()) {
				if (element.matchTagName(tagName))
					return element;
				// if ancestor element has end tag stop search
				break;
			}
			if (element.getNextSibling() != null)
				break;
		}

		return null;
	}

	/**
	 */
	Text findNextText() {
		Node node = this.nextNode;
		while (node != null) {
			if (node != this.nextNode && node.getNodeType() == Node.TEXT_NODE) {
				TextImpl text = (TextImpl) node;
				// skip empty text
				if (text.getStructuredDocumentRegion() != null)
					return text;
			}
			Node child = node.getFirstChild();
			if (child != null) {
				node = child;
				continue;
			}
			while (node != null) {
				Node next = node.getNextSibling();
				if (next != null) {
					node = next;
					break;
				}
				node = node.getParentNode();
			}
		}
		return null;
	}

	/**
	 * findPreviousText method
	 * 
	 * @return org.w3c.dom.Text
	 */
	Text findPreviousText() {
		if (this.parentNode == null)
			return null;
		Node node = null;
		if (this.nextNode != null)
			node = this.nextNode.getPreviousSibling();
		else
			node = this.parentNode.getLastChild();
		if (node == null || node.getNodeType() != Node.TEXT_NODE)
			return null;
		return (Text) node;
	}

	/**
	 * findStartTag method
	 * 
	 * @return org.w3c.dom.Element
	 * @param tagName
	 *            java.lang.String
	 */
	Element findStartTag(String tagName, String rootName) {
		if (tagName == null)
			return null;

		// check previous for empty content element
		Node prev = null;
		if (this.nextNode != null)
			prev = this.nextNode.getPreviousSibling();
		else if (this.parentNode != null)
			prev = this.parentNode.getLastChild();
		if (prev != null && prev.getNodeType() == Node.ELEMENT_NODE) {
			ElementImpl element = (ElementImpl) prev;
			if (!element.hasEndTag() && !element.isEmptyTag() && element.matchTagName(tagName))
				return element;
		}

		for (Node parent = this.parentNode; parent != null; parent = parent.getParentNode()) {
			if (parent.getNodeType() != Node.ELEMENT_NODE)
				break;
			ElementImpl element = (ElementImpl) parent;
			if (element.matchTagName(tagName))
				return element;
			if (rootName != null && element.matchTagName(rootName))
				break;
		}

		return null;
	}

	/**
	 * getNextNode method
	 * 
	 * @return org.w3c.dom.Node
	 */
	Node getNextNode() {
		return this.nextNode;
	}

	/**
	 * getParentNode method
	 * 
	 * @return org.w3c.dom.Node
	 */
	Node getParentNode() {
		return this.parentNode;
	}

	/**
	 * getRootNode method
	 * 
	 * @return org.w3c.dom.Node
	 */
	Node getRootNode() {
		return this.rootNode;
	}

	/**
	 * setLast method
	 */
	void setLast() {
		if (this.parentNode == null)
			return;
		if (this.nextNode != null) {
			Node prev = this.nextNode.getPreviousSibling();
			if (prev == null || prev.getNodeType() != Node.ELEMENT_NODE)
				return;
			ElementImpl element = (ElementImpl) prev;
			if (element.hasEndTag() || !element.isContainer() || element.isEmptyTag())
				return;
			setParentNode(prev);
		}

		// find last open parent
		Node parent = this.parentNode;
		Node last = parent.getLastChild();
		while (last != null) {
			if (last.getNodeType() != Node.ELEMENT_NODE)
				break;
			ElementImpl element = (ElementImpl) last;
			if (element.hasEndTag() || !element.isContainer() || element.isEmptyTag())
				break;
			parent = element;
			last = parent.getLastChild();
		}
		if (parent != this.parentNode)
			setParentNode(parent);
	}

	/**
	 * setNextNode method
	 * 
	 * @param nextNode
	 *            org.w3c.dom.Node
	 */
	void setNextNode(Node nextNode) {
		this.nextNode = nextNode;
		if (nextNode == null)
			return;
		this.parentNode = nextNode.getParentNode();
	}

	/**
	 * setParentNode method
	 * 
	 * @param parentNode
	 *            org.w3c.dom.Node
	 */
	void setParentNode(Node parentNode) {
		this.parentNode = parentNode;
		this.nextNode = null;
	}
}