/*
    * JaspertReports JSF Plugin Copyright (C) 2011 A. Alonso Dominguez
    *
    * This library is free software; you can redistribute it and/or modify it
    * under the terms of the GNU Lesser General Public License as published by
    * the Free Software Foundation; either version 2.1 of the License, or (at
    * your option) any later version. This library is distributed in the hope
    * that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
    * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   *
   * See the GNU Lesser General Public License for more details. You should have
   * received a copy of the GNU Lesser General Public License along with this
   * library; if not, write to the Free Software Foundation, Inc., 59 Temple
   * Place, Suite 330, Boston, MA 02111-1307 USA A.
   *
   * Alonso Dominguez
   * alonsoft@users.sf.net
   */
  package net.sf.jasperreports.jsf.context;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.List;
  
  import javax.faces.context.ExternalContext;
  import javax.servlet.ServletContext;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import net.sf.jasperreports.jsf.Constants;
  import net.sf.jasperreports.jsf.component.UIReport;
  import net.sf.jasperreports.jsf.config.Configuration;
  import net.sf.jasperreports.jsf.renderkit.ReportRenderer;
  
  /**
   * Servlet implementation of the external context helper.
   *
   * @author A. Alonso Dominguez
   */
  final class ServletContextHelper extends ExternalContextHelper {
  	
      /**
       * Private constructor to prevent instantiation.
       */
      protected ServletContextHelper() { }
  
      /**
       * Creates a <code>ReportRenderRequest</code> based on the data code in the
       * current ExternalContext.
       *
       * @param context the current ExternalContext
       * @return A representation of the request render request
       */
      @Override
      public ReportRenderRequest restoreReportRequest(
              final ExternalContext context) {
          final Configuration config = Configuration.getInstance(context);
          final String viewId = context.getRequestParameterMap()
                  .get(Constants.PARAM_VIEWID);
          final String viewState = getViewCacheMap(context).get(viewId);
  
          HttpServletRequest request = (HttpServletRequest) context.getRequest();
          request = new ReportHttpRenderRequest(request, viewId,
                  config.getDefaultMapping(), viewState);
          context.setRequest(request);
          return (ReportRenderRequest) request;
      }
  
      @Override
      @SuppressWarnings("unchecked")
      public Collection<ContentType> getAcceptedContentTypes(
          final ExternalContext context) {
      	final HttpServletRequest request = (HttpServletRequest)
              context.getRequest();
      	
      	Enumeration<String> values = request.getHeaders("Accept");
      	List<ContentType> list = new ArrayList<ContentType>();
      	while (values.hasMoreElements()) {
              ContentType type = new ContentType(values.nextElement());
              list.add(type);
      	}
      	Collections.sort(list);
      	
      	return Collections.unmodifiableList(list);
      }
      
      /**
       * Obtains the server name of the current request.
       *
       * @param context the current ExternalContext
       * @return the server name
       */
      @Override
      public String getRequestServerName(final ExternalContext context) {
          final HttpServletRequest request = (HttpServletRequest)
                 context.getRequest();
         return request.getServerName();
     }
 
     /**
      * Gets the request uri.
      *
      * @param context the context
      * @return the request uri
      */
     @Override
     public String getRequestURI(final ExternalContext context) {
         final HttpServletRequest request = (HttpServletRequest)
                 context.getRequest();
         return request.getRequestURI();
     }
 
     /**
      * Obtains the real path name of the resource local to the current context.
      *
      * @param context the current ExternalContext
      * @param name the resource name
      * @return the resource real path name
      */
     @Override
     public String getResourceRealPath(final ExternalContext context,
             final String name) {
         final ServletContext ctx = (ServletContext) context.getContext();
         return ctx.getRealPath(name);
     }
 
     /**
      * Writes the report headers into the current response using the report
      * renderer.
      *
      * @param context the current ExternalContext
      * @param renderer the report renderer instance
      * @param report the report component instance
      * @throws IOException if any input or output error happens when writing
      *         the report headers
      */
     @Override
     public void writeHeaders(final ExternalContext context,
             final ReportRenderer renderer, final UIReport report)
             throws IOException {
         final HttpServletResponse response = (HttpServletResponse)
                 context.getResponse();
         response.setHeader("Cache-Type", "no-cache");
         response.setHeader("Expires", "0");
 
         if (report.getName() != null) {
             response.setHeader("Content-Disposition", 
                     renderer.encodeContentDisposition(report,
                     response.getCharacterEncoding()));
         }
     }
 
     /**
      * Writes the report contents into the context response.
      *
      * @param context the context
      * @param contentType the content type
      * @param data the data
      * @throws IOException Signals that an I/O exception has occurred.
      */
     @Override
     public void writeResponse(final ExternalContext context,
             final ContentType contentType, final InputStream stream) 
     throws IOException {
         final HttpServletResponse response = (HttpServletResponse)
                 context.getResponse();        
         response.setContentType(contentType.toString());
         
         int contentLength = 0;
         byte[] data = new byte[BUFFER_SIZE];
         int bytesRead;
         while (-1 != (bytesRead = stream.read(data))) {
         	response.getOutputStream().write(data, 0, bytesRead);
         	contentLength += bytesRead;
         }
         
         response.setContentLength(contentLength);
     }
 }