/**
    * Copyright [2006] [University Corporation for Advanced Internet Development, Inc.]
    *
    * 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 edu.internet2.middleware.shibboleth.wayf;
  
  import java.io.IOException;
  import java.io.UnsupportedEncodingException;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.net.URLDecoder;
  import java.net.URLEncoder;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Comparator;
  import java.util.Date;
  import java.util.HashSet;
  import java.util.Hashtable;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Set;
  import java.util.TreeSet;
  
  import javax.servlet.RequestDispatcher;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.opensaml.saml2.common.Extensions;
  import org.opensaml.saml2.metadata.EntityDescriptor;
  import org.opensaml.saml2.metadata.RoleDescriptor;
  import org.opensaml.saml2.metadata.SPSSODescriptor;
  import org.opensaml.samlext.idpdisco.DiscoveryResponse;
  import org.opensaml.xml.XMLObject;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.w3c.dom.Element;
  import org.w3c.dom.NodeList;
  
  import edu.internet2.middleware.shibboleth.common.ShibbolethConfigurationException;
  import edu.internet2.middleware.shibboleth.wayf.plugins.Plugin;
  import edu.internet2.middleware.shibboleth.wayf.plugins.PluginContext;
  import edu.internet2.middleware.shibboleth.wayf.plugins.PluginMetadataParameter;
  import edu.internet2.middleware.shibboleth.wayf.plugins.WayfRequestHandled;
  
  /**
    * Specific handler for each version of the Discovery Service. 
    */
  public class DiscoveryServiceHandler {
  
      /*
       * Protcol parameters - Old.
       */
      /**
       * Shire is the SP Assertion Consumer endpoint.
       */
      private static final String SHIRE_PARAM_NAME = "shire";
      /**
       * TargetName is where we are trying to get to.
       */
      private static final String TARGET_PARAM_NAME = "target";
      /**
       * time is to do with replay attack.
       */
      private static final String TIME_PARAM_NAME = "time";
      /**
       * This is the ID (in the metadata) of the SP.
       */
      private static final String PROVIDERID_PARAM_NAME = "providerId";
      
      /*
       * Protocol parameters - New
       */
      /**
       * The SP id.
       */
      private static final String ENTITYID_PARAM_NAME = "entityID";
      /**
       * Where to send the request back to.
       */
      private static final String RETURN_PARAM_NAME = "return";
      /**
       * "return" is an invalid attribute, so we use returnX.
       */
      private static final String RETURN_ATTRIBUTE_NAME = "returnX";
      /**
       * Alternatively the index of where to send the address back to.
      */
     private static final String RETURN_INDEX_NAME = "returnIndex";
     
     /**
      * What value to put the ID of the selected metadata into.
      */
     private static final String RETURNID_PARAM_NAME = "returnIDParam";
     
     /**
      * What returnIDParam defaults to.
      */
     private static final String RETURNID_DEFAULT_VALUE = "entityID";
     /**
      * Whether we are allowed to interact.
      */
     private static final String ISPASSIVE_PARAM_NAME = "isPassive";
     
     /**
      * Whether we understand this or not.
      */
     private static final String POLICY_PARAM_NAME = "policy";
 
     /**
      * The only policy we know about.
      */
     private static final String KNOWN_POLICY_NAME 
         = "urn:oasis:names:tc:SAML:profiles:SSO:idp-discoveryprotocol:single";
     
     /**
      * Mandatory Serialization constant.
      */
     private static final  Logger LOG = LoggerFactory.getLogger(DiscoveryServiceHandler.class.getName());
 
     /**
      * The location defines the last part of the URL which distinguished this handler. 
      */
     private final String location;
     
     /**
      * If isDefault is true then if there is a mismatch then this handler is used.  
      */
     private final boolean isDefault;
     
     /**
      * Config handles detailed behavior.
      */
     private final HandlerConfig config;
     
     /**
      * The list of all the metadata providers that this discovery handler believes in.
      */
     private final List <IdPSiteSet> siteSets;
     
     /**
      * The list of all the plugins that this hanlder has had configured.
      */
     private final List <Plugin> plugins;
     
     /**
      * Constructor to create and configure the handler.
      * @param config - DOM Element with configuration information.
      * @param federations - Supplies all known providers which will be included if so configured.
      * @param plugins - Supplies all known plugins which will be included if configured in. 
      * @param defaultConfig - The default configurations.
      * @throws ShibbolethConfigurationException - if we find something odd in the config file. 
      */
     protected DiscoveryServiceHandler(Element config, 
                                       Hashtable <String, IdPSiteSet> federations,
                                       Hashtable <String, Plugin> plugins, 
                                       HandlerConfig defaultConfig) throws ShibbolethConfigurationException
     {
         siteSets = new ArrayList <IdPSiteSet>(federations.size());
         this.plugins = new ArrayList <Plugin>(plugins.size());
 
         //
         // Collect the Configuration from the XML
         //
         
         this.config = new HandlerConfig(config, defaultConfig);
         
         location = config.getAttribute("location");
         
         if (location == null || location.equals("")) {
                 
                 LOG.error("DiscoveryService must have a location specified");
                 throw new ShibbolethConfigurationException("DiscoveryService must have a location specified");  
         }
         
         //
         // Is this the default WAYF?
         //
         
         String attribute = config.getAttribute("default");
         if (attribute != null && !attribute.equals("")) {
                 isDefault = Boolean.valueOf(attribute).booleanValue();
         } else {
                 isDefault = false;
         }
         
         //
         // Which federations (sitesets) do we care about?
         //
         
         NodeList list = config.getElementsByTagName("Federation");
                 
         for (int i = 0; i < list.getLength(); i++ ) {
                     
             attribute = ((Element) list.item(i)).getAttribute("identifier");
                     
                 IdPSiteSet siteset = federations.get(attribute);
                 
                 if (siteset == null) {
                     LOG.error("Handler " + location + ": could not find metadata for <Federation> with identifier " + attribute + ".");
                     throw new ShibbolethConfigurationException(
                            "Handler " + location + ": could not find metadata for  <Federation> identifier " + attribute + ".");
                 }
                 
                 siteSets.add(siteset);
         }
 
         if (siteSets.size() == 0) {
             //
             // No Federations explicitly named pick em all
             //
             siteSets.addAll(federations.values());
         }
         
         //
         // Now, which plugins?
         //
 
         list = config.getElementsByTagName("PluginInstance");
         
         for (int i = 0; i < list.getLength(); i++ ) {
                     
             attribute = ((Element) list.item(i)).getAttribute("identifier");
                     
                 Plugin plugin = plugins.get(attribute);
                 
                 if (plugin == null) {
                     LOG.error("Handler " + location + ": could not find plugin for identifier " + attribute);
                     throw new ShibbolethConfigurationException(
                               "Handler " + location + ": could not find plugin for identifier " + attribute);
                 }
                 
                 this.plugins.add(plugin);
         }
 
         //
         // So now tell every IdPSite about every plugin.
         //
         // Note that there is only one idpsite per metadatafile per WAYF and that the discovery 
         // services share them, so the data explosion is only number(IdpSites) * number(Plugins) not
         // number(IdpSites) * number(Plugins) * number(DiscoverHandlers)
         
         for (IdPSiteSet site: siteSets) {
             for (Plugin plugin: this.plugins) {
                 site.addPlugin(plugin);
             }
         }
     }
     
     
     //
     // Standard Beany Methods
     //
     /**
      * The 'Name' of the service. the path used to identify the ServiceHandler.
      * @return the path used to identify the ServiceHandler.
      */
     
     protected String getLocation() {
         return location;
     }
 
     /**
      * Whether this is the default service.
      * @return is it?
      */
     protected boolean isDefault() {
         return isDefault;
     }
     
     //
     // Now the bits that deal with the user request
     //
 
     public void doGet(HttpServletRequest req, HttpServletResponse res) {
         
         String policy = req.getParameter(POLICY_PARAM_NAME);
         
         if (null != policy && !KNOWN_POLICY_NAME.equals(policy)) {
             //
             // unknown policy
             //
             LOG.error("Unknown policy " + policy);
             handleError(req, res, "Unknown policy " + policy);
             return;
         }
         
         //
         // Decide how to route the request based on query string
         //
         String requestType = req.getParameter("action");
         
         if (requestType == null || requestType.equals("")) {
             requestType = "lookup";
         }
         
         try {
 
             if (requestType.equals("search")) {
                     
                 String parameter = req.getParameter("string"); 
                 if (parameter != null && parameter.equals("")) {
                         parameter = null;
                 }
                 handleLookup(req, res, parameter);
                     
             } else if (requestType.equals("selection")) {
                     
                 handleSelection(req, res);
             } else {
                 handleLookup(req, res, null);
             }
         } catch (WayfException we) {
             LOG.error("Error processing DS request:", we);
             handleError(req, res, we.getLocalizedMessage());
         } catch (WayfRequestHandled we) {
             //
             // Yuck - a sucess path involving an exception
             //
         }
 
     }
         
     /**
      * When the WAYF user has selected something we look it up, tell the plugins and then dispatch to the Idp.
      *  
      * @param req - standard J2EE stuff
      * @param res - standard J2EE stuff
      * @throws WayfRequestHandled - if one of the plugins has done the dispatch
      * @throws WayfException - if we had an errors
      */
     private void handleSelection(HttpServletRequest req, 
                                  HttpServletResponse res) throws WayfRequestHandled, WayfException 
      {
             
         String idpName = req.getParameter("origin");
         LOG.debug("Processing handle selection: " + idpName);
 
         String sPName = getSPId(req);
 
         if (idpName == null || idpName.equals("")) {
             handleLookup(req, res, null);
             return;
         }
 
         if (getValue(req, SHIRE_PARAM_NAME) == null) {
             //
             // 2.0 protocol
             //
             setupReturnAddress(sPName, req);
         }
         //
         // Notify plugins
         //
         IdPSite site = null; 
         
         for (Plugin plugin:plugins) {
             for (IdPSiteSet idPSiteSet: siteSets) {
                 PluginMetadataParameter param = idPSiteSet.paramFor(plugin);
                 plugin.selected(req, res, param, idpName);
                 if (site == null && idPSiteSet.containsIdP(idpName)) {
                     site = idPSiteSet.getSite(idpName);
                 }
             }
         }
         
         if (site == null) {
             handleLookup(req, res, null);
         } else {
             forwardRequest(req, res, site);
         }
     }
 
 
     /**
      * This sets up the parameter RETURN_ATTRIBUTE_NAME with the return address 
      * harvested from the reqest.
      * <ul><le>If a "return" parameter is present we check in the metadata for spoofing 
      *         and then set up from there </le>
      *     <le>If "returnID" is specified we get this from the metadata</le>
      *     <le>If nothing is provided we get the default from the metadata (if provided)</le>
      *     <le>Otherwise we whine</le>
      * </ul>     
      * @param spName - the name of the Service provider.
      * @param req - The request.
      * @throws WayfException - if we spot spoofing or there is no defaumlt 
      */
     private void setupReturnAddress(String spName, HttpServletRequest req) throws WayfException{
         
         DiscoveryResponse[] discoveryServices;
         Set<XMLObject> objects = new HashSet<XMLObject>();
         String defaultName = null;
         
         for (IdPSiteSet metadataProvider:siteSets) {
             
             //
             // Only do work if the SP makes sense
             //
 
             if (metadataProvider.containsSP(spName)) {
                
                 //
                 // The name makes sense so let's get the entity and from that
                 // all of its roles
                 //
                 
                 EntityDescriptor entity = metadataProvider.getEntity(spName);
                 List<RoleDescriptor> roles = entity.getRoleDescriptors();
                 
                 for (RoleDescriptor role:roles) {
                     
                     //
                     // Check every role
                     //
                     
                     if (role instanceof SPSSODescriptor) {
                         
                         //
                         // And grab hold of all the extensions for SPSSO descriptors
                         //
                         
                         Extensions exts = role.getExtensions();
                         if (exts != null) {
                             objects.addAll(exts.getOrderedChildren());
                         }
                     }
                 }
             }
         }
         
         //
         // Now, let's strip out everything which isn't a DiscoveryService
         //
         
         discoveryServices = new DiscoveryResponse[objects.size()];
         int dsCount = 0;
         
         for (XMLObject obj:objects) {
             if (obj instanceof DiscoveryResponse) {
                 DiscoveryResponse ds = (DiscoveryResponse) obj;
                 discoveryServices[dsCount++] = ds;
                 if (ds.isDefault() || null == defaultName) {
                     defaultName = ds.getLocation();
                 }
             }
         }
         
         //
         // Now process the return parameters.  The name is either a parameter
         // called RETURN_PARAM_NAME or an attributes called RETURN_ATTRIBUTE_NAME
         //
         String returnName = req.getParameter(RETURN_PARAM_NAME);
         
         if (returnName == null || returnName.length() == 0) {
             returnName = getValue(req, RETURN_ATTRIBUTE_NAME);
         }
         
         //
         // Return index is only ever a parameter
         //
         
         String returnIndex = req.getParameter(RETURN_INDEX_NAME);
         
         if (returnName != null && returnName.length() != 0) {
             //
             // Given something so we have to police it.
             //
             String nameNoParam = returnName;
             URL providedReturnURL;
             int index = nameNoParam.indexOf('?');
             boolean found = false;
             
             if (index >= 0) {
                 nameNoParam = nameNoParam.substring(0,index);
             }
             
             try {
                 providedReturnURL = new URL(nameNoParam);                
             } catch (MalformedURLException e) {
                 throw new WayfException("Couldn't parse provided return name " + nameNoParam, e);
             }
             
             
             for (DiscoveryResponse disc: discoveryServices) {
                 if (equalsURL(disc, providedReturnURL)) {
                     found = true;
                     break;
                 }
             }
             if (!found) {
                 throw new WayfException("Couldn't find endpoint " + nameNoParam + " in metadata");
             }
         } else if (returnIndex != null && returnIndex.length() != 0) {
             
             int index; 
             try {
                 index = Integer.parseInt(returnIndex);
             } catch (NumberFormatException e) {
                 throw new WayfException("Couldn't convert " + returnIndex + " into an index");
             }
             //
             // So look throught to find the endpoint with the correct index
             //
 
             boolean found = false;
             
             for (DiscoveryResponse disc: discoveryServices) {
                 if (index  == disc.getIndex()) {
                     found = true;
                     returnName = disc.getLocation();
                     break;
                 }
             }
             if (!found) {
                 throw new WayfException("Couldn't not find endpoint " + returnIndex + "in metadata");
             }
         } else {
             //
             // No name, not index, so we want the default
             //
             returnName = defaultName;
         }
         //
         // So by now returnName has the correct value, either harvested from or
         // policed against the metadata
         //
         req.setAttribute(RETURN_ATTRIBUTE_NAME, returnName);
     }
 
     /**
      * Helper function to see whather the provided endpoint in the metadata matches the 
      * provided return URL in the request.
      * 
      * @param discovery
      * @param providedName
      * @return
      */
     private static boolean equalsURL(DiscoveryResponse discovery, URL providedName) {
         
         //
         // Nothing provided - no match
         //
         if (null == discovery) {
             return false;
         }
         
         URL discoveryName;
         try {
             discoveryName = new URL(discovery.getLocation());
         } catch (MalformedURLException e) {
             //
             // Something bad happened.  Log it (it is only of interest to the sysadmin, not to the user)
             //
             LOG.warn("Found invalid discovery end point : " + discovery.getLocation(), e);
             return false;
         }
         
         return providedName.equals(discoveryName);
         
     }
 
     /**
      * Displays a Discovery Service selection page, having first consulted the plugins as needed.
      * @param req Describes the request
      * @param res Describes the response
      * @param searchName What are we looking for?
      * 
      * @throws WayfRequestHandled if a plugin has dealt with the request
      * @throws WayfException in case of an error.
      */
     private void handleLookup(HttpServletRequest req, 
                               HttpServletResponse res, 
                               String searchName) throws WayfException, WayfRequestHandled {
         
         String shire = getValue(req, SHIRE_PARAM_NAME);
         String providerId = getSPId(req);
         boolean twoZeroProtocol = (shire == null);
         boolean isPassive = (twoZeroProtocol && 
                              "true".equalsIgnoreCase(getValue(req, ISPASSIVE_PARAM_NAME)));
 
         Collection <IdPSiteSetEntry> siteLists = null;
         Collection<IdPSite> searchResults = null;
         
         if (config.getProvideListOfLists()) {
             siteLists = new ArrayList <IdPSiteSetEntry>(siteSets.size());
         }
 
         Collection <IdPSite> sites = null;
         Comparator<IdPSite> comparator = new IdPSite.Compare(req);
        
         if (config.getProvideList()) {
             sites = new TreeSet<IdPSite>(comparator);
         }
 
         if (searchName != null && !searchName.equals("")) {
             searchResults = new TreeSet<IdPSite>(comparator);
         }
 
         LOG.debug("Processing Idp Lookup for : " + providerId);
 
         //
         // Iterate over all the sitesets and if they know about the SP pass them to the plugins
         // and then add them too the list
         //
 
         PluginContext[] ctx = new PluginContext[plugins.size()];
         List<IdPSite> hintList = new ArrayList<IdPSite>();
         
         if (twoZeroProtocol) {
             setupReturnAddress(providerId, req);
         }
         //
         // By having siteLists and sites as parameters we only iterate over 
         // the metadata arrays once.
         //
         try {   
             for (IdPSiteSet metadataProvider:siteSets) {
                 
                 //
                 // Only do work if the SP makes sense
                 //
 
                 if (metadataProvider.containsSP(providerId) || !config.getLookupSp()) {
 
                     Collection <IdPSite> search = null;
                     
                     if (searchResults != null) {
                         search = new TreeSet<IdPSite>(comparator);
                     }
 
                     Map <String, IdPSite> theseSites = metadataProvider.getIdPSites(searchName, config, search);
                     
                     //
                     // Consult the plugins
                     //
                     for (int i = 0; i < plugins.size(); i++) {
                             
                         Plugin plugin = plugins.get(i);
                         
                         if (searchResults == null) {
                             //
                             // This was a search
                             //
                             ctx[i] = plugin.lookup(req, 
                                                    res, 
                                                    metadataProvider.paramFor(plugin), 
                                                    theseSites, 
                                                    ctx[i], 
                                                    hintList);
                         } else {
                             ctx[i] = plugin.search(req, 
                                                    res, 
                                                    metadataProvider.paramFor(plugin), 
                                                    searchName, 
                                                    theseSites, 
                                                    ctx[i], 
                                                    searchResults, 
                                                    hintList);
                         }
                     }
                     
                     if (null == theseSites || theseSites.isEmpty()) {
                         continue;
                     }
                     
                     //
                         
                     // Accumulate any per-metadata provider information
                     // 
             
                     Collection<IdPSite> values = new TreeSet<IdPSite>(comparator);
                     if (null != theseSites) {
                         values.addAll(theseSites.values());
                     }
                     
                     if (siteLists != null) {
                         siteLists.add(new IdPSiteSetEntry(metadataProvider,values));
                     }
                             
                     if (sites != null) {
                         sites.addAll(values);
                     }
                     
                     if (searchResults != null) {
                         searchResults.addAll(search);
                     }
                 }
             }
             
             if (isPassive) {
                 //
                 // No GUI intervention.
                 //
                 if (0 != hintList.size()) {
                     //
                     // We found a candidate, hand it back
                     //
                     forwardRequest(req, res, hintList.get(0));
                 } else {
                     forwardRequest(req, res, null);
                 }   
                 return;
             }
             
             //
             // Now set up all the funky stuff that the JSP needs.  Firstly the protocol
             // specific parameters which will come back to us
             //
             
             if (twoZeroProtocol) {
                 //
                 // The return address was set up in setupReturnAddress
                 //
                 String returnString = (String) req.getAttribute(RETURN_ATTRIBUTE_NAME);
                 if (null == returnString || 0 == returnString.length()) {
                     throw new WayfException("Parameter " + RETURN_PARAM_NAME + " not supplied");
                 }
 
                 String returnId = getValue(req, RETURNID_PARAM_NAME);
                 if (null == returnId || 0 == returnId.length()) {
                     returnId = RETURNID_DEFAULT_VALUE;
                 }
                 //
                 // Return *means* something so we cannot use it as an attribute
                 //
                 req.setAttribute(RETURN_ATTRIBUTE_NAME, returnString);
                 req.setAttribute(RETURNID_PARAM_NAME, returnId);
                 req.setAttribute(ENTITYID_PARAM_NAME, providerId);
                 
             } else {
                 String target = getValue(req, TARGET_PARAM_NAME);
                 if (null == target || 0 == target.length()) {
                     throw new WayfException("Could not extract target from provided parameters");
                 }
                 req.setAttribute(SHIRE_PARAM_NAME, shire);
                 req.setAttribute(TARGET_PARAM_NAME, target);
                 req.setAttribute(PROVIDERID_PARAM_NAME, providerId);
                 //
                 // Time is in unix format
                 //
                 req.setAttribute("time", new Long(new Date().getTime() / 1000).toString()); 
                 
             }
             
             //
             // Setup the stuff that the GUI wants.  
             //
                 
             setDisplayLanguage(sites, req);
             req.setAttribute("sites", sites);
             if (null != siteLists) {
                 for (IdPSiteSetEntry siteSetEntry:siteLists) {
                     setDisplayLanguage(siteSetEntry.getSites(), req);
                 }
             }
                 
             req.setAttribute("siteLists", siteLists);
             req.setAttribute("requestURL", req.getRequestURI().toString());
 
             if (searchResults != null) {
                 if (searchResults.size() != 0) {
                     setDisplayLanguage(searchResults, req);
                     req.setAttribute("searchresults", searchResults);
                 } else {
                     req.setAttribute("searchResultsEmpty", "true");
                 }
             }
 
             if (hintList.size() > 0) {
                 setDisplayLanguage(hintList, req);
                 req.setAttribute("cookieList", hintList);
             }
 
             LOG.debug("Displaying WAYF selection page.");
             RequestDispatcher rd = req.getRequestDispatcher(config.getJspFile());
 
             //
             // And off to the jsp
             //
             rd.forward(req, res);
         } catch (IOException ioe) {
             LOG.error("Problem displaying WAYF UI.\n" +  ioe.getMessage());
             throw new WayfException("Problem displaying WAYF UI", ioe);
         } catch (ServletException se) {
             LOG.error("Problem displaying WAYF UI.\n" +  se.getMessage());
             throw new WayfException("Problem displaying WAYF UI", se);
         }
     }
 
     /**
      * Prior to display we set the display language from the
      * browser. There is probably a proper way to do this using
      * jsp, but I want to keep the API between JSP and java the same 1.3->2.0
      * @param sites - the sites we need to impact
      * @param req - from whiuch we get the locale
      */
     private void setDisplayLanguage(Collection<IdPSite> sites, HttpServletRequest req) {
         
         if (null == sites) {
             return;
         }
         Locale locale = req.getLocale();
         if (null == locale) {
             Locale.getDefault();
         }
         String lang = locale.getLanguage();
 
         for (IdPSite site : sites) {
             site.setDisplayLanguage(lang);
         }
     }
 
 
     /**
      * Uses an HTTP Status 307 redirect to forward the user to the IdP or the SP.
      * 
      * @param req request under consideration
      * @param res response under construction
      * @param site The Idp
      * @throws WayfException if bad things happen.
      */
     public static void forwardRequest(HttpServletRequest req, HttpServletResponse res, IdPSite site)
                     throws WayfException {
 
         String shire = getValue(req, SHIRE_PARAM_NAME);
         String providerId = getSPId(req);
         boolean twoZeroProtocol = (shire == null);
 
         if (!twoZeroProtocol) {
             String handleService = site.getAddressForWAYF(); 
             if (handleService != null ) {
 
                 String target = getValue(req, TARGET_PARAM_NAME);
                 if (null == target || 0 == target.length()) {
                     throw new WayfException("Could not extract target from provided parameters");
                 }
 
                 LOG.info("Redirecting to selected Handle Service: " + handleService);
                 try {
                     StringBuffer buffer = new StringBuffer(handleService +  
                        "?" + TARGET_PARAM_NAME + "=");
                     buffer.append(URLEncoder.encode(target, "UTF-8"));
                     buffer.append("&" + SHIRE_PARAM_NAME + "=");
                     buffer.append(URLEncoder.encode(shire, "UTF-8"));
                     buffer.append("&" + PROVIDERID_PARAM_NAME + "=");
                     buffer.append(URLEncoder.encode(providerId, "UTF-8"));
                          
                     //
                     // Time is as per U**X
                     //
                     buffer.append("&" +  TIME_PARAM_NAME + "=");
                     buffer.append(new Long(new Date().getTime() / 1000).toString());
                     res.sendRedirect(buffer.toString());
                 } catch (IOException ioe) {
                     //
                     // That failed.  
                     //
                     throw new WayfException("Error forwarding to IdP: \n" + ioe.getMessage());
                 }
             } else {
                 String s = "Error finding to IdP: " + site.getDisplayName(req); 
                 LOG.error(s);
                 throw new WayfException(s);
             }
         } else {
             String returnUrl = (String) req.getAttribute(RETURN_ATTRIBUTE_NAME);
             
             if (null == returnUrl || 0 == returnUrl.length()) {
                 throw new WayfException("Could not find return parameter");
             }
             try {
                 returnUrl = URLDecoder.decode(returnUrl, "UTF-8");
             } catch (UnsupportedEncodingException e) {
                 throw new WayfException("Did not understand parameter ", e);
             }
             String redirect;
             if (site != null) {
                 StringBuffer buffer = new StringBuffer(returnUrl);
                 //
                 // If we were given anybody to lookup, construct the URL
                 //
                 String returnParam = getValue(req, RETURNID_PARAM_NAME);
                 if (null == returnParam || 0 == returnParam.length()) {
                     returnParam = RETURNID_DEFAULT_VALUE;
                 }              
                 //
                 // Do we add a '?' or a '&' for the parameters
                 //
 
                 if (returnUrl.indexOf('?') >= 0) {
                     //
                     // there is a parameter already.  Add a '&'
                     //
                     buffer.append("&" + returnParam + "=");
                 } else {
                     //
                     // No parameter.  Use ?
                     //
                     buffer.append("?" + returnParam + "=");
                 }
                 buffer.append(site.getName());
                 redirect =  buffer.toString();
             } else {
                 //
                 // Just send it back
                 //
                 redirect = returnUrl;
             }
             
             LOG.debug("Dispatching to " + redirect);
             
             try {
                 res.sendRedirect(redirect);
             } catch (IOException ioe) {
                 //
                 // That failed.  
                 //
                 throw new WayfException("Error forwarding back to Sp: \n" + ioe.getMessage());
             }         
         }
     }
 
     /**
      * Handles all "recoverable" errors in WAYF processing by logging the error and forwarding the user to an
      * appropriate error page.
      * 
      * @param req request under consideration
      * @param res response under construction
      * @param message - what so say
      */
     private void handleError(HttpServletRequest req, HttpServletResponse res, String message) {
 
         LOG.debug("Displaying WAYF error page.");
         req.setAttribute("errorText", message);
         req.setAttribute("requestURL", req.getRequestURI().toString());
         RequestDispatcher rd = req.getRequestDispatcher(config.getErrorJspFile());
 
         try {
             rd.forward(req, res);
         } catch (IOException ioe) {
             LOG.error("Problem trying to display WAYF error page: " + ioe.toString());
         } catch (ServletException se) {
             LOG.error("Problem trying to display WAYF error page: " + se.toString());
         }
     }
 
     /**
      * Gets the value for the parameter either from the parameter or from jsp.
      * @param req - the request.
      * @param name - the name of the parameter.
      * @return - result
      */
     private static String getValue(HttpServletRequest req, String name) {
 
         
         String value = req.getParameter(name); 
         if (value != null) {
             return value;
         }
         return (String) req.getAttribute(name);
     }
 
     private static String getSPId(HttpServletRequest req) throws WayfException {
 
         //
         // Try first with 2.0 version
         //
         String param = req.getParameter(ENTITYID_PARAM_NAME);
         if (param != null && !(param.length() == 0)) {
             return param;
         } 
         
         param = (String) req.getAttribute(ENTITYID_PARAM_NAME);
         if (param != null && !(param.length() == 0)) {
             return param;
         }       
         //
         // So Try with 1.3 version
         //
         param = req.getParameter(PROVIDERID_PARAM_NAME);
         if (param != null && !(param.length() == 0)) {
             return param;
         } 
         
         param = (String) req.getAttribute(PROVIDERID_PARAM_NAME);
         if (param != null && !(param.length() == 0)) {
             return param;
         } 
         throw new WayfException("Could not locate SP identifier in parameters");
     }   
 }