/*
    * Copyright 2004 Jeff Johnston
    *
    * 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.extremecomponents.table.filter;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  import javax.servlet.Filter;
  import javax.servlet.FilterChain;
  import javax.servlet.FilterConfig;
  import javax.servlet.ServletException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.apache.avalon.framework.logger.ConsoleLogger;
  import org.apache.avalon.framework.logger.Logger;
  import org.apache.commons.lang.StringUtils;
  import org.apache.fop.apps.Driver;
  import org.apache.fop.messaging.MessageHandler;
  import org.apache.poi.hssf.usermodel.HSSFWorkbook;
  import org.extremecomponents.table.bean.Table;
  import org.extremecomponents.table.model.ExportHandler;
  import org.extremecomponents.table.model.ParameterRegistry;
  import org.xml.sax.InputSource;
  
  
  
  /***
   *  Filter to handle the incoming FOP requests to generate the PDF document.  
   * 
   * 
   *   	  <filter>
   *  			<filter-name>ExportFilter</filter-name>
   *  			<display-name>ExportFilter</display-name>
   *  			<filter-class>org.extremecomponents.table.filter.ExportFilter</filter-class>
   *  		</filter>
   *  		<filter-mapping>
   *  			<filter-name>ExportFilter</filter-name>
   *  			<url-pattern>*</url-pattern>
   *  		</filter-mapping>
   *
   *			<!-- Action Servlet Configuration -->
   *			<filter-mapping>
   *			<filter-name>ExportFilter</filter-name>
   *				<servlet-name>eXtremeTest</servlet-name>
   *			</filter-mapping>
   * @author jeff johnston
   */
  public final class ExportFilter implements Filter
  {
  	private FilterConfig filterConfig = null;
  	private Logger log = null;
  
  	public void init(FilterConfig filterConfig)
  		throws ServletException
  	{
  		this.filterConfig = filterConfig;
  	}
  
  	public void destroy()
  	{
  		this.filterConfig = null;
  	}
  
  	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
  		throws IOException, ServletException
  	{
  		String tableKey = request.getParameter(Table.EXTREME_TABLE); 
  		
  		String invokeExport = null;
  		String exportName = null;
  		if (StringUtils.isNotBlank(tableKey))
  		{
  			invokeExport = request.getParameter(tableKey +ParameterRegistry.EXPORT);
  			exportName = request.getParameter(tableKey +ExportHandler.EXPORT_NAME);
  		}
  
  		if (StringUtils.isNotBlank(invokeExport))
  		{
  			setResponseHeaders((HttpServletRequest) request, (HttpServletResponse) response, exportName); //set the headers right away
  			GenericResponseWrapper wrapper = new GenericResponseWrapper((HttpServletResponse) response);
  			chain.doFilter(request, wrapper);
 		}
 		else
 		{
 			chain.doFilter(request, response);
 		}
 
 		if (StringUtils.isNotBlank(invokeExport))
 		{
 			try
 			{
 				if (exportName.endsWith(ExportHandler.PDF))
 					handlePDF(request, response);
 				else if (exportName.endsWith(ExportHandler.XLS))
 					handleXLS(request, response);
 			}
 			catch (Exception e)
 			{
 				e.printStackTrace();
 			}
 		}
 	}
 	
 	public void handleXLS(ServletRequest request, ServletResponse response) throws Exception
 	{
 		HSSFWorkbook wb = (HSSFWorkbook) request.getAttribute(ExportHandler.EXPORT_DATA);
 		wb.write(response.getOutputStream());
 		response.getOutputStream().flush();
 		response.getOutputStream().close();
 	}
 	
 	public void handlePDF(ServletRequest request, ServletResponse response) throws Exception
 	{
 		String output = (String)request.getAttribute(ExportHandler.EXPORT_DATA);
 		InputStream is = new ByteArrayInputStream(output.getBytes());
 		renderFO(new InputSource(is), (HttpServletResponse) response);
 	}
 
 	public void renderFO(InputSource foFile, HttpServletResponse response)
 		throws Exception
 	{
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
 
 		Driver driver = new Driver(foFile, out);
 
 		if (log == null)
 		{
 			log = new ConsoleLogger(ConsoleLogger.LEVEL_WARN);
 			MessageHandler.setScreenLogger(log);
 		}
 
 		driver.setLogger(log);
 		driver.setRenderer(Driver.RENDER_PDF);
 		driver.run();
 
 		byte[] content = out.toByteArray();
 		response.setContentLength(content.length);
 		response.getOutputStream().write(content);
 		response.getOutputStream().flush();
 	}
 	
 	public void setResponseHeaders(HttpServletRequest request, HttpServletResponse response, String exportName)
 	{
 		if (exportName.endsWith(ExportHandler.PDF))
 			response.setContentType("application/pdf");
 		else if (exportName.endsWith(ExportHandler.XLS))
 			response.setContentType("application/vnd.ms-excel");
 
 		response.setHeader("Content-Disposition", "attachment;filename=\"" + exportName + "\"");
 
 //		if (request.getScheme().equalsIgnoreCase("https"))
 //		{
 			//SSL must enable caching or it will fail
 			response.setHeader("Pragma", "public");
 			response.setDateHeader("Expires", (System.currentTimeMillis() + 1000));
 //		}
 //		else
 //		{
 //			response.setHeader("pragma", "no-cache");
 //			response.setHeader("Cache-Control", "no-cache");
 //			response.setHeader("Cache-Control", "no-store");
 //			response.setDateHeader("Expires", (System.currentTimeMillis() + 1000));
 //		}
 	}	
 }