/*******************************************************************************
 * Copyright (c) 2008 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
 *******************************************************************************/

package org.eclipse.wst.xml.ui.internal.actions;

import java.util.ResourceBundle;

import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.swt.widgets.Event;
import org.eclipse.ui.texteditor.ITextEditor;
import org.eclipse.ui.texteditor.TextEditorAction;
import org.w3c.dom.Attr;
import org.w3c.dom.Node;

/**
 * Provides navigation to next/previous DOM sibling Nodes
 * 
 * @author nitin
 * 
 */
class SiblingNavigationAction extends TextEditorAction {

	private boolean fForward;

	/**
	 * @param bundle
	 * @param prefix
	 * @param editor
	 */
	SiblingNavigationAction(ResourceBundle bundle, String prefix, ITextEditor editor, boolean forward) {
		super(bundle, prefix, editor);
		fForward = forward;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.action.Action#runWithEvent(org.eclipse.swt.widgets.Event)
	 */
	public void runWithEvent(Event event) {
		super.runWithEvent(event);
		if (getTextEditor() == null)
			return;

		ISelection selection = getTextEditor().getSelectionProvider().getSelection();
		if (!selection.isEmpty() && selection instanceof IStructuredSelection) {
			Object o = ((IStructuredSelection) selection).getFirstElement();
			if (o instanceof Node) {
				Node sibling = null;

				if (((Node) o).getNodeType() == Node.ATTRIBUTE_NODE) {
					o = ((Attr) o).getOwnerElement();
				}
				if (fForward) {
					sibling = ((Node) o).getNextSibling();
					while (sibling != null && sibling.getNodeType() == Node.TEXT_NODE && sibling.getNodeValue().trim().length() == 0) {
						sibling = sibling.getNextSibling();
					}
					if (sibling == null) {
						sibling = ((Node) o).getParentNode().getFirstChild();
						while (sibling != null && sibling.getNodeType() == Node.TEXT_NODE && sibling.getNodeValue().trim().length() == 0) {
							sibling = sibling.getNextSibling();
						}
					}
				}
				else {
					sibling = ((Node) o).getPreviousSibling();
					while (sibling != null && sibling.getNodeType() == Node.TEXT_NODE && sibling.getNodeValue().trim().length() == 0) {
						sibling = sibling.getPreviousSibling();
					}
					if (sibling == null) {
						sibling = ((Node) o).getParentNode().getLastChild();
						while (sibling != null && sibling.getNodeType() == Node.TEXT_NODE && sibling.getNodeValue().trim().length() == 0) {
							sibling = sibling.getPreviousSibling();
						}
					}
				}

				// The only child is a Text Node, go to the parent Node
				if (((Node) o).getNodeType() == Node.TEXT_NODE && o.equals(sibling)) {
					sibling = ((Node) o).getParentNode();
				}


				if (sibling != null) {
					getTextEditor().getSelectionProvider().setSelection(new StructuredSelection(sibling));
				}
			}
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.texteditor.TextEditorAction#update()
	 */
	public void update() {

	}
}