/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.apache.axis2.fastinfoset;

import com.sun.xml.fastinfoset.stax.StAXDocumentSerializer;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMOutputFormat;
import org.apache.axis2.AxisFault;
import org.apache.axis2.Constants;
import org.apache.axis2.context.MessageContext;
import org.apache.axis2.transport.MessageFormatter;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Iterator;

public class FastInfosetPOXMessageFormatter implements MessageFormatter {

    private static Log logger = LogFactory.getLog(FastInfosetMessageFormatter.class);
    
    /**
     * Plain Fast Infoset message formatter doesn't need to handle SOAP. Hence do nothing.
     * 
     * @see org.apache.axis2.transport.MessageFormatter#formatSOAPAction(org.apache.axis2.context.MessageContext, org.apache.axiom.om.OMOutputFormat, java.lang.String)
     */
    public String formatSOAPAction(MessageContext messageContext,
            OMOutputFormat format, String soapAction) {

        return null;
    }

    /**
     * Returns the content type
     * 
     * @see org.apache.axis2.transport.MessageFormatter#getContentType(org.apache.axis2.context.MessageContext, org.apache.axiom.om.OMOutputFormat, java.lang.String)
     */
    public String getContentType(MessageContext messageContext,
            OMOutputFormat format, String soapAction) {
        String contentType = (String) messageContext.getProperty(Constants.Configuration.CONTENT_TYPE);
        String encoding = format.getCharSetEncoding();
        
        //If the Content Type is not available with the property "Content Type" retrieve it from the property "Message Type"
        if (contentType == null) {
            contentType = (String) messageContext.getProperty(Constants.Configuration.MESSAGE_TYPE);
        }

        if (encoding != null) {
            contentType += "; charset=" + encoding;
        }
            
        return contentType;
    }

    /**
     * Returns the target address to send the response
     * FIXME This is very HTTP specific. What about other transport?
     * 
     * @see org.apache.axis2.transport.MessageFormatter#getTargetAddress(org.apache.axis2.context.MessageContext, org.apache.axiom.om.OMOutputFormat, java.net.URL)
     */
    public URL getTargetAddress(MessageContext messageContext,
            OMOutputFormat format, URL targetURL) throws AxisFault {
        String httpMethod =
            (String) messageContext.getProperty(Constants.Configuration.HTTP_METHOD);

        URL targetAddress = targetURL; //Let's initialize to this
        //if the http method is GET, parameters are attached to the target URL
        if ((httpMethod != null)
                && Constants.Configuration.HTTP_METHOD_GET.equalsIgnoreCase(httpMethod)) {
            String param = getParam(messageContext);
    
            if (param.length() > 0) {
                String returnURLFile = targetURL.getFile() + "?" + param;
                try {
                    targetAddress = 
                        new URL(targetURL.getProtocol(), targetURL.getHost(), targetURL.getPort(), returnURLFile);
                } catch (MalformedURLException murle) {
                    logger.error(murle.getMessage());
                    throw new AxisFault(murle.getMessage(), murle);
                }
            }
        }
        
        return targetAddress;
    }

    /**
     * Write the SOAP envelop to the given OutputStream.
     * 
     * @see org.apache.axis2.transport.MessageFormatter#writeTo(org.apache.axis2.context.MessageContext, org.apache.axiom.om.OMOutputFormat, java.io.OutputStream, boolean)
     */
    public void writeTo(MessageContext messageContext, OMOutputFormat format,
            OutputStream outputStream, boolean preserve) throws AxisFault {
        //For POX drop the SOAP envelope and use the message body
        OMElement element = messageContext.getEnvelope().getBody().getFirstElement();
        
        try {
            //Create the StAX document serializer
            XMLStreamWriter streamWriter = new StAXDocumentSerializer(outputStream);
            //Since we drop the SOAP envelop we have to manually write the start document and the end document events            
            streamWriter.writeStartDocument();
            element.serialize(streamWriter, preserve);
            streamWriter.writeEndDocument();
        } catch (XMLStreamException xmlse) {
            logger.error(xmlse.getMessage());
            throw new AxisFault(xmlse.getMessage(), xmlse);
        }
    }
    
    /**
     * Construct URL parameters like, "param1=value1&param2=value2"
     * FIXME This is very HTTP specific. What about other transports
     * 
     * @param messageContext
     * @return Formatted URL parameters
     */
    private String getParam(MessageContext messageContext) {
        
        OMElement dataOut = messageContext.getEnvelope().getBody().getFirstElement();
        Iterator it = dataOut.getChildElements();
        StringBuffer paramBuffer = new StringBuffer();
 
        while (it.hasNext()) {
            OMElement element = (OMElement) it.next();
            String parameter = element.getLocalName() + "=" + element.getText();
            paramBuffer.append(parameter);
            paramBuffer.append("&");
        }
        //We don't need a '&' at the end
        paramBuffer.deleteCharAt(paramBuffer.length() - 1);
        
        return paramBuffer.toString();
    }
}