/*******************************************************************************

 * Copyright (c) 2000, 2006 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.core.internal.resources;

import java.io.IOException;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.List;

import javax.xml.parsers.*;

import org.eclipse.core.internal.localstore.SafeFileInputStream;

import org.eclipse.core.internal.utils.Messages;

import org.eclipse.core.internal.utils.Policy;

import org.eclipse.core.resources.IResourceStatus;

import org.eclipse.core.runtime.IPath;

import org.eclipse.osgi.util.NLS;

import org.w3c.dom.*;

import org.xml.sax.SAXException;

/**

 * This class contains legacy code only.  It is being used to read workspace

 * descriptions which are obsolete.

 */

public class WorkspaceDescriptionReader implements IModelObjectConstants {

	/** constants */

	protected static final String[] EMPTY_STRING_ARRAY = new String[0];

	public WorkspaceDescriptionReader() {

		super();

	}

	protected String getString(Node target, String tagName) {

		Node node = searchNode(target, tagName);

		return node != null ? (node.getFirstChild() == null ? null : node.getFirstChild().getNodeValue()) : null;

	}

	protected String[] getStrings(Node target) {

		if (target == null)

			return null;

		NodeList list = target.getChildNodes();

		if (list.getLength() == 0)

			return EMPTY_STRING_ARRAY;

		List result = new ArrayList(list.getLength());

		for (int i = 0; i < list.getLength(); i++) {

			Node node = list.item(i);

			if (node.getNodeType() == Node.ELEMENT_NODE)

				result.add(read(node.getChildNodes().item(0)));

		}

		return (String[]) result.toArray(new String[result.size()]);

	}

	/**

	 * A value was discovered in the workspace description file that was not a number.

	 * Log the exception.

	 */

	private void logNumberFormatException(String value, NumberFormatException e) {

		String msg = NLS.bind(Messages.resources_readWorkspaceMetaValue, value);

		Policy.log(new ResourceStatus(IResourceStatus.FAILED_READ_METADATA, null, msg, e));

	}

	public Object read(InputStream input) {

		try {

			DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();

			Document document = parser.parse(input);

			return read(document.getFirstChild());

		} catch (IOException e) {

			// ignore

		} catch (SAXException e) {

			// ignore

		} catch (ParserConfigurationException e) {

			// ignore

		}

		return null;

	}

	public Object read(IPath location, IPath tempLocation) throws IOException {

		SafeFileInputStream file = new SafeFileInputStream(location.toOSString(), tempLocation.toOSString());

		try {

			return read(file);

		} finally {

			file.close();

		}

	}

	protected Object read(Node node) {

		if (node == null)

			return null;

		switch (node.getNodeType()) {

			case Node.ELEMENT_NODE :

				if (node.getNodeName().equals(WORKSPACE_DESCRIPTION))

					return readWorkspaceDescription(node);

			case Node.TEXT_NODE :

				String value = node.getNodeValue();

				return value == null ? null : value.trim();

			default :

				return node.toString();

		}

	}

	/**

	 * read (String, String) hashtables

	 */

	protected WorkspaceDescription readWorkspaceDescription(Node node) {

		// get values

		String name = getString(node, NAME);

		String autobuild = getString(node, AUTOBUILD);

		String snapshotInterval = getString(node, SNAPSHOT_INTERVAL);

		String fileStateLongevity = getString(node, FILE_STATE_LONGEVITY);

		String maxFileStateSize = getString(node, MAX_FILE_STATE_SIZE);

		String maxFileStates = getString(node, MAX_FILE_STATES);

		String[] buildOrder = getStrings(searchNode(node, BUILD_ORDER));

		// build instance

		//invalid values are skipped and defaults are used instead

		WorkspaceDescription description = new WorkspaceDescription(name);

		if (autobuild != null)

			//if in doubt (value is corrupt) we want autobuild on

			description.setAutoBuilding(!autobuild.equals(Integer.toString(0)));

		try {

			if (fileStateLongevity != null)

				description.setFileStateLongevity(Long.parseLong(fileStateLongevity));

		} catch (NumberFormatException e) {

			logNumberFormatException(fileStateLongevity, e);

		}

		try {

			if (maxFileStateSize != null)

				description.setMaxFileStateSize(Long.parseLong(maxFileStateSize));

		} catch (NumberFormatException e) {

			logNumberFormatException(maxFileStateSize, e);

		}

		try {

			if (maxFileStates != null)

				description.setMaxFileStates(Integer.parseInt(maxFileStates));

		} catch (NumberFormatException e) {

			logNumberFormatException(maxFileStates, e);

		}

		if (buildOrder != null)

			description.internalSetBuildOrder(buildOrder);

		try {

			if (snapshotInterval != null)

				description.setSnapshotInterval(Long.parseLong(snapshotInterval));

		} catch (NumberFormatException e) {

			logNumberFormatException(snapshotInterval, e);

		}

		return description;

	}

	protected Node searchNode(Node target, String tagName) {

		NodeList list = target.getChildNodes();

		for (int i = 0; i < list.getLength(); i++) {

			if (list.item(i).getNodeName().equals(tagName))

				return list.item(i);

		}

		return null;

	}

}