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/*
 * 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 jakarta.faces.context;

import java.io.IOException;
import java.util.Iterator;
import java.util.Map;

/**
 * @since 2.0
 */
public class PartialResponseWriter extends ResponseWriterWrapper
{
    public static final String RENDER_ALL_MARKER = "jakarta.faces.ViewRoot";
    public static final String VIEW_STATE_MARKER = "jakarta.faces.ViewState";

    private boolean hasChanges;
    private String insertType;

    public PartialResponseWriter(ResponseWriter writer)
    {
        super(writer);
    }

    public void delete(String targetId) throws IOException
    {
        startChanges();
        
        startElement("delete", null);
        writeAttribute("id", targetId, null);
        endElement("delete");
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void endDocument() throws IOException
    {
        if (hasChanges)
        {
            // Close the  element, if any.
            //error close the last op if any
            endInsert();
            
            endElement("changes");
            
            hasChanges = false;
        }
        
        endElement("partial-response");
    }

    public void endError() throws IOException
    {
        // Close open  element.
        
        endCDATA();
        endElement("error-message");
        endElement("error");
    }

    public void endEval() throws IOException
    {
        // Close open  element.
        
        endCDATA();
        endElement("eval");
    }

    public void endExtension() throws IOException
    {
        endElement("extension");
    }

    public void endInsert() throws IOException
    {
        if (insertType == null)
        {
            // No insert started; ignore.
            
            return;
        }
        
        // Close open  element.
        
        endCDATA();
        endElement(insertType);
        endElement("insert");
        
        insertType = null;
    }

    public void endUpdate() throws IOException
    {
        endCDATA();
        endElement("update");
    }

    public void redirect(String url) throws IOException
    {
        startElement("redirect", null);
        writeAttribute("url", url, null);
        endElement("redirect");
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void startDocument() throws IOException
    {
        // Faces 2.2 section 2.2.6.1 Render Response Partial Processing

        String encoding = getCharacterEncoding();
        if (encoding == null)
        {
            encoding = "UTF-8";
        }

        String preamble = "";

        writePreamble(preamble); // MYFACES-4501

        startElement("partial-response", null);
        
        // If by some reason the response has been reset, and the same
        // PartialResponseWriter is used, it is necessary to ensure any 
        // variable is initialized in a consistent state. To do that,
        // the best point is when the document is started.
        hasChanges = false;
        insertType = null;
    }

    public void startError(String errorName) throws IOException
    {
        startElement("error", null);
        
        startElement("error-name", null);
        write(errorName);
        endElement("error-name");
        
        startElement("error-message", null);
        startCDATA();
        
        // Leave open; caller will write message.
    }

    public void startEval() throws IOException
    {
        startChanges();
        
        startElement("eval", null);
        startCDATA();
        
        // Leave open; caller will write statements.
    }

    public void startExtension(Map attributes) throws IOException
    {
        Iterator attrNames;
        
        startChanges();
        
        startElement("extension", null);
        
        // Write out extension attributes.
        // TODO: schema mentions "id" attribute; not used?
        
        attrNames = attributes.keySet().iterator();
        
        while (attrNames.hasNext())
        {
            String attrName = attrNames.next();
            
            writeAttribute(attrName, attributes.get(attrName), null);
        }
        
        // Leave open; caller will write extension elements.
    }

    public void startInsertAfter(String targetId) throws IOException
    {
        startInsertCommon ("after", targetId);
    }

    public void startInsertBefore(String targetId) throws IOException
    {
        startInsertCommon ("before", targetId);
    }

    public void startUpdate(String targetId) throws IOException
    {
        startChanges();
        
        startElement("update", null);
        writeAttribute("id", targetId, null);
        startCDATA();
        
        // Leave open; caller will write content.
    }

    public void updateAttributes(String targetId, Map attributes) throws IOException
    {
        Iterator attrNames;
        
        startChanges();
        
        startElement("attributes", null);
        writeAttribute("id", targetId, null);
        
        attrNames = attributes.keySet().iterator();
        
        while (attrNames.hasNext())
        {
            String attrName = attrNames.next();
            
            startElement("attribute", null);
            writeAttribute("name", attrName, null);
            writeAttribute("value", attributes.get (attrName), null);
            endElement("attribute");
        }
        
        endElement("attributes");
    }
    
    private void startChanges () throws IOException
    {
        if (!hasChanges)
        {
            startElement("changes", null);
            
            hasChanges = true;
        }
    }
    
    private void startInsertCommon (String type, String targetId) throws IOException
    {
        if (insertType != null)
        {
            // An insert has already been started; ignore.
            
            return;
        }
        
        insertType = type;
        
        startChanges();
        
        startElement("insert", null);
        startElement(insertType, null);
        writeAttribute("id", targetId, null);
        startCDATA();
        
        // Leave open; caller will write content.
    }
}