/*
    * $Id: ResourceListServlet.java 1537 2011-07-27 15:34:04Z hoheisel $
    *
    * Copyright (c) 2007
    * Fraunhofer Institute for Computer Architecture and Software Technology
    * See http://www.first.fraunhofer.de for more details.
    */
   
   package net.kwfgrid.gwes.servlet;
  
  import net.kwfgrid.gwes.client.RemoteGWES;
  import net.kwfgrid.gwes.exception.GWESException;
  import org.antlr.stringtemplate.StringTemplate;
  import org.apache.log4j.Logger;
  
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.util.*;
  
  /**
   * Servlet that shows a list of all resources.
   * Security should be implemented by means of the Servlet container (e.g. using tomcat-users.xml)
   *
   * @author Andreas Hoheisel
   *         (<a href="http://www.andreas-hoheisel.de">www.andreas-hoheisel.de</a>)
   * @version $Id: ResourceListServlet.java 1537 2011-07-27 15:34:04Z hoheisel $
   */
  public class ResourceListServlet extends HttpServlet {
  
      private static GWESProperties pr;
      final static Logger logger = Logger.getLogger(ResourceListServlet.class);
  
      protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
          ServletLogger.log(request);
  
          response.setContentType("text/html");
          PrintWriter out = response.getWriter();
          String error = null;
          String success = null;
          String info = null;
  
          Object obj = request.getAttribute("error");
          if (obj instanceof String) error = (String) obj;
  
          obj = request.getAttribute("success");
          if (obj instanceof String) success = (String) obj;
  
          obj = request.getAttribute("info");
          if (obj instanceof String) info = (String) obj;
  
          //read gwes.properties
          if (pr == null) pr = GWESProperties.getInstance("/gwes.properties");
  
          // get user
          String userID = request.getRemoteUser();
          if (userID == null) userID = "nn";
  
          List<ResourceInformation> resources = null;
  
              try {
                  resources = gatherResourcesArray(pr.gwesBaseUrlExternal, request.getUserPrincipal().getName());
              } catch (Throwable e) {
                      out.println("<hr><b>ERROR connecting to GWES: " + e + "</b>");
                      out.println("<pre>");
                      e.printStackTrace(out);
                      out.println("</pre>");
                      out.println("<hr>");
              }
  
          try {
              StringTemplate t = Template.getStringTemplateGroup("html_gwes-servlets").getInstanceOf("listResources");
              // listResources(menu,error,success,info,resources,gwesBaseUrlExternal)
              t.setAttribute("menu", new Menu(pr.gwesBaseUrlExternal, "Resources"));
              if (resources == null || resources.size() == 0) info = "Currently there are no resources available. Please check the resource registry.";
              else t.setAttribute("resources", resources);
              if (success != null) t.setAttribute("success", success);
              if (error != null) t.setAttribute("error", error);
              if (info != null) t.setAttribute("info", info);
              t.setAttribute("gwesBaseUrlExternal", pr.gwesBaseUrlExternal);
              out.print(t.toString());
          } catch (Exception e) {
              logger.error("exception: " + e, e);
              error = ((error == null) ? "" : error) + "Could not display resource list: " + e.getMessage();
          }
      }
  
      protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
          doGet(request, response);
      }
  
      private List<ResourceInformation> gatherResourcesArray(String gwesBaseUrlExternal, String userID) throws Exception, GWESException {
          String[] resourceArray = RemoteGWES.getInstance().getAvailableResources(null, userID);
          if (resourceArray == null) return null;
          List<ResourceInformation> resources = new ArrayList<ResourceInformation>(resourceArray.length);
          for (String resourceStr : resourceArray) {
             ResourceInformation resource = new ResourceInformation(gwesBaseUrlExternal, resourceStr);
             resources.add(resource);
         }
 
         Collections.sort(resources, new ResourceComparator(ResourceComparator.COMPARE_URI));
 
         return resources;
     }
 
 }