/*
 * Copyright 2010 NCHOVY
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.krakenapps.util;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.SAXException;

public class XmlUtil {
	private static Logger logger = LoggerFactory.getLogger(XmlUtil.class);

	public static Document read(InputStream inputStream) {
		try {
			DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
			DocumentBuilder builder = factory.newDocumentBuilder();
			return builder.parse(inputStream);
		} catch (ParserConfigurationException e) {
			logger.error(e.getMessage());
		} catch (SAXException e) {
			logger.error(e.getMessage());
		} catch (IOException e) {
			logger.error(e.getMessage());
		} finally {
			if (inputStream != null)
				try {
					inputStream.close();
				} catch (IOException e) {
					// ignore.
				}
		}
		return null;
	}

	public static Document parse(String buffer) {
		try {
			DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
			DocumentBuilder builder = documentBuilderFactory.newDocumentBuilder();
			InputStream is = new ByteArrayInputStream(buffer.getBytes("utf-8"));
			return builder.parse(is);
		} catch (ParserConfigurationException e) {
			logger.error(e.getMessage());
		} catch (SAXException e) {
			logger.error(e.getMessage());
		} catch (IOException e) {
			logger.error(e.getMessage());
		}
		return null;
	}

	public static Document parse(byte[] buffer) {
		try {
			DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
			DocumentBuilder builder = documentBuilderFactory.newDocumentBuilder();
			InputStream is = new ByteArrayInputStream(buffer);
			return builder.parse(is);
		} catch (ParserConfigurationException e) {
			logger.error(e.getMessage());
		} catch (SAXException e) {
			logger.error(e.getMessage());
		} catch (IOException e) {
			logger.error(e.getMessage());
		}
		return null;
	}

	public static Document newDocument() {
		try {
			DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
			DocumentBuilder builder = documentBuilderFactory.newDocumentBuilder();
			return builder.newDocument();
		} catch (ParserConfigurationException e) {
			logger.error(e.getMessage());
		}
		return null;
	}

	public static XPathExpression compileXPath(String expression) {
		try {
			XPathFactory xPathFactory = XPathFactory.newInstance();
			XPath xPath = xPathFactory.newXPath();
			return xPath.compile(expression);
		} catch (XPathExpressionException e) {
			logger.error("Invalid XPath expression [" + expression + "]");
			return null;
		}
	}

	public static String getAttribute(Node node, String attributeName) {
		Node attribute = node.getAttributes().getNamedItem(attributeName);
		if (attribute == null) {
			return null;
		}

		return attribute.getTextContent();
	}

	public static String toXmlString(Document document) {
		StringWriter sw = new StringWriter();
		StreamResult result = new StreamResult(sw);
		Transformer transformer;
		try {
			transformer = TransformerFactory.newInstance().newTransformer();
			transformer.transform(new DOMSource(document.getLastChild()), result);
		} catch (TransformerConfigurationException e) {
			e.printStackTrace();
		} catch (TransformerFactoryConfigurationError e) {
			e.printStackTrace();
		} catch (TransformerException e) {
			e.printStackTrace();
		}
		return sw.toString();
	}
}