/*
 * Copyright 2005-2010 the original author or authors.
 *
 * 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.springframework.ws.client.support.destination;

import java.io.IOException;
import java.net.URI;
import java.util.HashMap;
import java.util.Map;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMResult;

import org.w3c.dom.Document;

import org.springframework.core.io.Resource;
import org.springframework.util.Assert;
import org.springframework.ws.client.WebServiceIOException;
import org.springframework.ws.client.WebServiceTransformerException;
import org.springframework.xml.transform.ResourceSource;
import org.springframework.xml.xpath.XPathExpression;
import org.springframework.xml.xpath.XPathExpressionFactory;

/**
 * Implementation of the {@link DestinationProvider} that resolves a destination URI from a WSDL file.
 *
 * <p>The extraction relies on an XPath expression to locate the URI. By default, the {@link
 * #DEFAULT_WSDL_LOCATION_EXPRESSION} will be used, but this expression can be overridden by setting the {@link
 * #setLocationExpression(String) locationExpression} property.
 *
 * @author Tareq Abed Rabbo
 * @author Arjen Poutsma
 * @since 1.5.4
 */
public class Wsdl11DestinationProvider extends AbstractCachingDestinationProvider {

	/** Default XPath expression used for extracting all {@code location} attributes from the WSDL definition. */
	public static final String DEFAULT_WSDL_LOCATION_EXPRESSION =
			"/wsdl:definitions/wsdl:service/wsdl:port/soap:address/@location";

	private static TransformerFactory transformerFactory = TransformerFactory.newInstance();

	private Map<String, String> expressionNamespaces = new HashMap<String, String>();

	private XPathExpression locationXPathExpression;

	private Resource wsdlResource;

	public Wsdl11DestinationProvider() {
		expressionNamespaces.put("wsdl", "http://schemas.xmlsoap.org/wsdl/");
		expressionNamespaces.put("soap", "http://schemas.xmlsoap.org/wsdl/soap/");
		expressionNamespaces.put("soap12", "http://schemas.xmlsoap.org/wsdl/soap12/");

		locationXPathExpression = XPathExpressionFactory
				.createXPathExpression(DEFAULT_WSDL_LOCATION_EXPRESSION, expressionNamespaces);
	}

	/** Sets a WSDL location from which the service destination {@code URI} will be resolved. */
	public void setWsdl(Resource wsdlResource) {
		Assert.notNull(wsdlResource, "'wsdl' must not be null");
		Assert.isTrue(wsdlResource.exists(), wsdlResource + " does not exist");
		this.wsdlResource = wsdlResource;
	}

	/**
	 * Sets the XPath expression to use when extracting the service location {@code URI} from a WSDL.
	 *
	 * <p>The expression can use the following bound prefixes: <blockquote> <table> <tr><th>Prefix</th><th>Namespace</th></tr>
	 * <tr><td>{@code wsdl}</td><td>{@code http://schemas.xmlsoap.org/wsdl/}</td></tr>
	 * <tr><td>{@code soap}</td><td>{@code http://schemas.xmlsoap.org/wsdl/soap/}</td></tr>
	 * <tr><td>{@code soap12}</td><td>{@code http://schemas.xmlsoap.org/wsdl/soap12/}</td></tr>
	 * </table></blockquote>
	 *
	 * <p>Defaults to {@link #DEFAULT_WSDL_LOCATION_EXPRESSION}.
	 */
	public void setLocationExpression(String expression) {
		Assert.hasText(expression, "'expression' must not be empty");
		locationXPathExpression = XPathExpressionFactory
				.createXPathExpression(expression, expressionNamespaces);
	}

	@Override
	protected URI lookupDestination() {
		try {
			DOMResult result = new DOMResult();
			Transformer transformer = transformerFactory.newTransformer();
			transformer.transform(new ResourceSource(wsdlResource), result);
			Document definitionDocument = (Document) result.getNode();
			String location = locationXPathExpression.evaluateAsString(definitionDocument);
			if (logger.isDebugEnabled()) {
				logger.debug("Found location [" + location + "] in " + wsdlResource);
			}
			return location != null ? URI.create(location) : null;
		}
		catch (IOException ex) {
			throw new WebServiceIOException("Error extracting location from WSDL [" + wsdlResource + "]", ex);
		}
		catch (TransformerException ex) {
			throw new WebServiceTransformerException("Error extracting location from WSDL [" + wsdlResource + "]", ex);
		}
	}

}