/*
    * 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 org.apache.myfaces.lifecycle;
  
  import java.io.IOException;
  import java.net.URI;
  import java.net.URISyntaxException;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import javax.el.MethodExpression;
  import javax.faces.FacesException;
  import javax.faces.FactoryFinder;
  import javax.faces.application.Application;
  import javax.faces.application.ProjectStage;
  import javax.faces.application.ProtectedViewException;
  import javax.faces.application.ViewExpiredException;
  import javax.faces.application.ViewHandler;
  import javax.faces.component.UIViewRoot;
  import javax.faces.context.ExternalContext;
  import javax.faces.context.FacesContext;
  import javax.faces.event.PhaseEvent;
  import javax.faces.event.PhaseId;
  import javax.faces.event.PostAddToViewEvent;
  import javax.faces.flow.FlowHandler;
  import javax.faces.lifecycle.ClientWindow;
  import javax.faces.lifecycle.Lifecycle;
  import javax.faces.lifecycle.LifecycleFactory;
  import javax.faces.render.RenderKit;
  import javax.faces.render.RenderKitFactory;
  import javax.faces.render.ResponseStateManager;
  import javax.faces.view.ViewDeclarationLanguage;
  import javax.faces.view.ViewMetadata;
  import javax.faces.webapp.FacesServlet;
  import javax.servlet.http.HttpServletResponse;
  import org.apache.myfaces.event.PostClientWindowAndViewInitializedEvent;
  
  import org.apache.myfaces.renderkit.ErrorPageWriter;
  import org.apache.myfaces.shared.config.MyfacesConfig;
  import org.apache.myfaces.shared.util.ExternalContextUtils;
  import org.apache.myfaces.shared.util.ViewProtectionUtils;
  
  /**
   * Implements the Restore View Phase (JSF Spec 2.2.1)
   * 
   * @author Nikolay Petrov (latest modification by $Author$)
   * @author Bruno Aranda (JSF 1.2)
   * @version $Revision$ $Date$
   */
  class RestoreViewExecutor extends PhaseExecutor
  {
  
      //private static final Log log = LogFactory.getLog(RestoreViewExecutor.class);
      private static final Logger log = Logger.getLogger(RestoreViewExecutor.class.getName());
      
      private RestoreViewSupport _restoreViewSupport;
      
      private Boolean _viewNotFoundCheck;
      
      private RenderKitFactory _renderKitFactory = null;
      
      @Override
      public void doPrePhaseActions(FacesContext facesContext)
      {
          // Call initView() on the ViewHandler. 
          // This will set the character encoding properly for this request.
          // Note that we are doing this here, because we need the character encoding
          // to be set as early as possible (before any PhaseListener is executed).
          facesContext.getApplication().getViewHandler().initView(facesContext);
      }
  
      public boolean execute(FacesContext facesContext)
      {
          if (facesContext == null)
          {
              throw new FacesException("FacesContext is null");
          }
  
          // get some required Objects
          Application application = facesContext.getApplication();
          ViewHandler viewHandler = application.getViewHandler();
          UIViewRoot viewRoot = facesContext.getViewRoot();
          RestoreViewSupport restoreViewSupport = getRestoreViewSupport(facesContext);
 
         // Examine the FacesContext instance for the current request. If it already contains a UIViewRoot
         if (viewRoot != null)
         {
             if (log.isLoggable(Level.FINEST))
             {
                 log.finest("View already exists in the FacesContext");
             }
             
             // Set the locale on this UIViewRoot to the value returned by the getRequestLocale() method on the
             // ExternalContext for this request
             viewRoot.setLocale(facesContext.getExternalContext().getRequestLocale());
             
             restoreViewSupport.processComponentBinding(facesContext, viewRoot);
             
             // invoke the afterPhase MethodExpression of UIViewRoot
             _invokeViewRootAfterPhaseListener(facesContext);
             
             return false;
         }
         
         String viewId = restoreViewSupport.calculateViewId(facesContext);
 
         // Determine if the current request is an attempt by the 
         // servlet container to display an error page.
         // If the request is an error page request, the servlet container
         // is required to set the request parameter "javax.servlet.error.message".
         final boolean errorPageRequest = facesContext.getExternalContext().getRequestMap()
                                                  .get("javax.servlet.error.message") != null;
         
         // Determine if this request is a postback or an initial request.
         // But if it is an error page request, do not treat it as a postback (since 2.0)
         if (!errorPageRequest && restoreViewSupport.isPostback(facesContext))
         { // If the request is a postback
             if (log.isLoggable(Level.FINEST))
             {
                 log.finest("Request is a postback");
             }
 
             if (checkViewNotFound(facesContext))
             {
                 String derivedViewId = viewHandler.deriveLogicalViewId(facesContext, viewId);
                 ViewDeclarationLanguage vdl = viewHandler.getViewDeclarationLanguage(facesContext, 
                     derivedViewId);
             
                 // viewHandler.deriveLogicalViewId() could trigger an InvalidViewIdException, which
                 // it is handled internally sending a 404 error code set the response as complete.
                 if (facesContext.getResponseComplete())
                 {
                     return true;
                 }
             
                 if (vdl == null || derivedViewId == null)
                 {
                     sendSourceNotFound(facesContext, viewId);
                     return true;
                 }
                 else if (!restoreViewSupport.checkViewExists(facesContext, derivedViewId))
                 {
                     sendSourceNotFound(facesContext, viewId);
                     return true;
                 }
             }
             
             try
             {
                 facesContext.setProcessingEvents(false);
                 // call ViewHandler.restoreView(), passing the FacesContext instance for the current request and the 
                 // view identifier, and returning a UIViewRoot for the restored view.
                 
                 viewRoot = viewHandler.restoreView(facesContext, viewId);
                 if (viewRoot == null)
                 {
                     if (facesContext.getResponseComplete())
                     {
                         // If the view handler cannot restore the view and the response
                         // is complete, it can be an error or some logic in restoreView.
                         return true;
                     }
                     else
                     {
                         // If the return from ViewHandler.restoreView() is null, throw a ViewExpiredException with an 
                         // appropriate error message.
                         throw new ViewExpiredException("No saved view state could be found for the view identifier: "
                                                    + viewId, viewId);
                     }
                 }
                 // If the view is transient (stateless), it is necessary to check the view protection
                 // in POST case.
                 if (viewRoot.isTransient())
                 {
                     checkViewProtection(facesContext, viewHandler, viewRoot.getViewId(), viewRoot);
                 }
                 
                 // Store the restored UIViewRoot in the FacesContext.
                 facesContext.setViewRoot(viewRoot);
             }
             finally
             {
                 facesContext.setProcessingEvents(true);
             }
             
             // Restore binding
             // See https://javaserverfaces-spec-public.dev.java.net/issues/show_bug.cgi?id=806
             restoreViewSupport.processComponentBinding(facesContext, viewRoot);
             
             ClientWindow clientWindow = facesContext.getExternalContext().getClientWindow();
             if (clientWindow != null)
             {
                 // The idea of this event is once the client window and the view is initialized, 
                 // you have the information required to clean up any scope that belongs to old
                 // clientWindow instances like flow scope (in server side state saving).
                 facesContext.getApplication().publishEvent(facesContext, PostClientWindowAndViewInitializedEvent.class, 
                         clientWindow);
             }
         }
         else
         { // If the request is a non-postback
             if (log.isLoggable(Level.FINEST))
             {
                 log.finest("Request is not a postback. New UIViewRoot will be created");
             }
             
             //viewHandler.deriveViewId(facesContext, viewId)
             //restoreViewSupport.deriveViewId(facesContext, viewId)
             String logicalViewId = viewHandler.deriveLogicalViewId(facesContext, viewId);
             ViewDeclarationLanguage vdl = viewHandler.getViewDeclarationLanguage(facesContext, logicalViewId);
             
             // viewHandler.deriveLogicalViewId() could trigger an InvalidViewIdException, which
             // it is handled internally sending a 404 error code set the response as complete.
             if (facesContext.getResponseComplete())
             {
                 return true;
             }
             
             if (checkViewNotFound(facesContext))
             {
                 if (vdl == null || logicalViewId == null)
                 {
                     sendSourceNotFound(facesContext, viewId);
                     return true;
                 }
                 else if (!restoreViewSupport.checkViewExists(facesContext, logicalViewId))
                 {
                     sendSourceNotFound(facesContext, viewId);
                     return true;
                 }
             }
             
             if (vdl != null)
             {
                 ViewMetadata metadata = vdl.getViewMetadata(facesContext, viewId);
                 
                 if (metadata != null)
                 {
                     viewRoot = metadata.createMetadataView(facesContext);
                     
                     if(facesContext.getResponseComplete())
                     {
                         // this can happen if the current request is a debug request,
                         // in this case no further processing is necessary
                         return true;
                     }
                 }
     
                 if (viewRoot == null)
                 {
                     facesContext.renderResponse();
                 }
                 else if (viewRoot != null && !ViewMetadata.hasMetadata(viewRoot))
                 {
                     facesContext.renderResponse();
                 }
             }
             else
             {
                 // Call renderResponse
                 facesContext.renderResponse();
             }
 
             checkViewProtection(facesContext, viewHandler, logicalViewId, viewRoot);
             
             // viewRoot can be null here, if ...
             //   - we don't have a ViewDeclarationLanguage (e.g. when using facelets-1.x)
             //   - there is no view metadata or metadata.createMetadataView() returned null
             if (viewRoot == null)
             {
                 // call ViewHandler.createView(), passing the FacesContext instance for the current request and 
                 // the view identifier
                 viewRoot = viewHandler.createView(facesContext, viewId);
             }
             
             if (viewRoot == null && facesContext.getResponseComplete())
             {
                 // If the view handler cannot create the view and the response
                 // is complete, it can be an error, just get out of the algorithm.
                 return true;
             }
             
             // Subscribe the newly created UIViewRoot instance to the AfterAddToParent event, passing the 
             // UIViewRoot instance itself as the listener.
             // -= Leonardo Uribe =- This line it is not necessary because it was
             // removed from jsf 2.0 section 2.2.1 when pass from EDR2 to Public Review 
             // viewRoot.subscribeToEvent(PostAddToViewEvent.class, viewRoot);
             
             // Store the new UIViewRoot instance in the FacesContext.
             facesContext.setViewRoot(viewRoot);
 
             ClientWindow clientWindow = facesContext.getExternalContext().getClientWindow();
             if (clientWindow != null)
             {
                 facesContext.getApplication().publishEvent(facesContext, PostClientWindowAndViewInitializedEvent.class, 
                         clientWindow);
             }
             
             FlowHandler flowHandler = facesContext.getApplication().getFlowHandler();
             if (flowHandler != null)
             {
                 flowHandler.clientWindowTransition(facesContext);
             }
 
             // Publish an AfterAddToParent event with the created UIViewRoot as the event source.
             application.publishEvent(facesContext, PostAddToViewEvent.class, viewRoot);
         }
 
         // add the ErrorPageBean to the view map to fully support 
         // facelet error pages, if we are in ProjectStage Development
         // and currently generating an error page
         if (errorPageRequest && facesContext.isProjectStage(ProjectStage.Development))
         {
             facesContext.getViewRoot().getViewMap()
                     .put(ErrorPageWriter.ERROR_PAGE_BEAN_KEY, new ErrorPageWriter.ErrorPageBean());
         }
         
         // invoke the afterPhase MethodExpression of UIViewRoot
         _invokeViewRootAfterPhaseListener(facesContext);
         
         return false;
     }
     
     private void checkViewProtection(FacesContext facesContext, ViewHandler viewHandler, 
         String viewId, UIViewRoot root) throws ProtectedViewException
     {
         boolean valid = true;
         if (ViewProtectionUtils.isViewProtected(facesContext, viewId))
         {
             // "... Obtain the value of the value of the request parameter whose 
             // name is given by the value of ResponseStateManager.NON_POSTBACK_VIEW_TOKEN_PARAM. 
             // If there is no value, throw ProtectedViewException ..."
             String token = (String) facesContext.getExternalContext().getRequestParameterMap().get(
                 ResponseStateManager.NON_POSTBACK_VIEW_TOKEN_PARAM);
             if (token != null && token.length() > 0)
             {
                 String renderKitId = null;
                 if (root != null)
                 {
                     renderKitId = root.getRenderKitId();
                 }
                 if (renderKitId == null)
                 {
                     renderKitId = viewHandler.calculateRenderKitId(facesContext);
                 }
                 RenderKit renderKit = getRenderKitFactory().getRenderKit(facesContext, renderKitId);
                 ResponseStateManager rsm = renderKit.getResponseStateManager();
                 
                 String storedToken = rsm.getCryptographicallyStrongTokenFromSession(facesContext);
                 if (token.equals(storedToken))
                 {
                     if (!ExternalContextUtils.isPortlet(facesContext.getExternalContext()))
                     {
                         // Any check beyond this point only has sense for servlet requests.
                         String referer = facesContext.getExternalContext().
                             getRequestHeaderMap().get("Referer");
                         if (referer != null)
                         {
                             valid = valid && checkRefererOrOriginHeader(
                                 facesContext, viewHandler, referer);
                         }
                         String origin = facesContext.getExternalContext().
                             getRequestHeaderMap().get("Origin");
                         if (valid && origin != null)
                         {
                             valid = valid && checkRefererOrOriginHeader(
                                 facesContext, viewHandler, origin);
                         }
                     }
                 }
                 else
                 {
                     valid = false;
                 }
             }
             else
             {
                 valid = false;
             }
         }
         if (!valid)
         {
             throw new ProtectedViewException();
         }
     }
     
     private boolean checkRefererOrOriginHeader(FacesContext facesContext, 
         ViewHandler viewHandler, String refererOrOrigin)
     {
         try
         {
             // The referer can be absolute or relative. 
             ExternalContext ectx = facesContext.getExternalContext();
             URI refererURI = new URI(refererOrOrigin);
             String path = refererURI.getPath();
             String appContextPath = ectx.getApplicationContextPath();
             if (refererURI.isAbsolute())
             {
                 // Check if the referer comes from the same host
                 String host = refererURI.getHost();
                 int port = refererURI.getPort();
                 String serverHost = ectx.getRequestServerName();
                 int serverPort = ectx.getRequestServerPort();
 
                 boolean matchPort = true;
                 if (serverPort != -1 && port != -1)
                 {
                     matchPort = (serverPort == port);
                 }
                 boolean isStrictJsf2OriginHeaderAppPath = 
                                 MyfacesConfig.getCurrentInstance(ectx).isStrictJsf2OriginHeaderAppPath();
                 if (!path.equals(""))
                 {
                     if (serverHost.equals(host) && matchPort && path.contains(appContextPath))
                     {
                         // Referer Header match
                     }
                     else
                     {
                         // Referer Header does not match
                         return false;
                     }
                 }
                 else
                 {
                     if (serverHost.equals(host) && matchPort && !isStrictJsf2OriginHeaderAppPath)
                     {
                         // Origin Header match and 
                         // STRICT_JSF_2_ORIGIN_HEADER_APP_PATH property is set to false (default)
                         // Because we don't want to strictly follow JSF 2.x spec
                     }
                     else
                     {
                         // Origin Header does not match
                         return false;
                     }
                 }
             }
             // In theory path = appContextPath + servletPath + pathInfo. 
             int appContextPathIndex = appContextPath != null ? path.indexOf(appContextPath) : -1;
             int servletPathIndex = -1;
             int pathInfoIndex = -1;
             if (ectx.getRequestServletPath() != null && ectx.getRequestPathInfo() != null)
             {
                 servletPathIndex = ectx.getRequestServletPath() != null ? 
                     path.indexOf(ectx.getRequestServletPath(), 
                                  appContextPathIndex >= 0 ? appContextPathIndex : 0) : -1;
                 if (servletPathIndex != -1)
                 {
                     pathInfoIndex = servletPathIndex + ectx.getRequestServletPath().length();
                 }
             }
             else
             {
                 servletPathIndex = -1;
                 pathInfoIndex = (appContextPathIndex >= 0 ? appContextPathIndex : 0) + appContextPath.length();
             }
 
             // If match appContextPath(if any) and match servletPath or pathInfo referer header is ok
             if ((appContextPath == null || appContextPathIndex >= 0) && 
                 (servletPathIndex >= 0 || pathInfoIndex >= 0))
             {
                 String refererViewId;
                 if (pathInfoIndex >= 0)
                 {
                     refererViewId = path.substring(pathInfoIndex);
                 }
                 else
                 {
                     refererViewId = path.substring(servletPathIndex);
                 }
                 
                 String logicalViewId = viewHandler.deriveViewId(facesContext, refererViewId);
                     
                 // If the header is present, use the protected view API to determine if any of
                 // the declared protected views match the value of the Referer header.
                 // - If so, conclude that the previously visited page is also a protected 
                 //   view and it is therefore safe to continue.
                 // - Otherwise, try to determine if the value of the Referer header corresponds 
                 //   to any of the views in the current web application.
                 // -= Leonardo Uribe =- All views that are protected also should exists!. the
                 // only relevant check is use ViewHandler.deriveViewId(...) here. Check if the
                 // view is protected here is not necessary.
                 if (logicalViewId != null)
                 {
                     return true;
                 }
                 else
                 {
                     // View do not exists
                 }
             }
             return true;
         }
         catch (URISyntaxException ex)
         {
             return false;
         }
     }
     
     /**
      * Invoke afterPhase MethodExpression of UIViewRoot.
      * Note: In this phase it is not possible to invoke the beforePhase method, because we
      * first have to restore the view to get its attributes. Also it is not really possible
      * to call the afterPhase method inside of UIViewRoot for this phase, thus it was decided
      * in the JSF 2.0 spec rev A to put this here.
      * @param facesContext
      */
     private void _invokeViewRootAfterPhaseListener(FacesContext facesContext)
     {
         // get the UIViewRoot (note that it must not be null at this point)
         UIViewRoot root = facesContext.getViewRoot();
         MethodExpression afterPhaseExpression = root.getAfterPhaseListener();
         if (afterPhaseExpression != null)
         {
             PhaseEvent event = new PhaseEvent(facesContext, getPhase(), _getLifecycle(facesContext));
             try
             {
                 afterPhaseExpression.invoke(facesContext.getELContext(), new Object[] { event });
             }
             catch (Throwable t) 
             {
                 log.log(Level.SEVERE, "An Exception occured while processing " +
                         afterPhaseExpression.getExpressionString() + 
                         " in Phase " + getPhase(), t);
             }
         }
     }
     
     /**
      * Gets the current Lifecycle instance from the LifecycleFactory
      * @param facesContext
      * @return
      */
     private Lifecycle _getLifecycle(FacesContext facesContext)
     {
         LifecycleFactory factory = (LifecycleFactory) FactoryFinder.getFactory(FactoryFinder.LIFECYCLE_FACTORY);
         String id = facesContext.getExternalContext().getInitParameter(FacesServlet.LIFECYCLE_ID_ATTR);
         if (id == null)
         {
             id = LifecycleFactory.DEFAULT_LIFECYCLE;
         }
         return factory.getLifecycle(id);  
     }
     
     protected RestoreViewSupport getRestoreViewSupport()
     {
         return getRestoreViewSupport(FacesContext.getCurrentInstance());
     }
     
     protected RestoreViewSupport getRestoreViewSupport(FacesContext context)
     {
         if (_restoreViewSupport == null)
         {
             _restoreViewSupport = new DefaultRestoreViewSupport(context);
         }
         return _restoreViewSupport;
     }
 
     protected RenderKitFactory getRenderKitFactory()
     {
         if (_renderKitFactory == null)
         {
             _renderKitFactory = (RenderKitFactory)FactoryFinder.getFactory(FactoryFinder.RENDER_KIT_FACTORY);
         }
         return _renderKitFactory;
     }
     
     /**
      * @param restoreViewSupport
      *            the restoreViewSupport to set
      */
     public void setRestoreViewSupport(RestoreViewSupport restoreViewSupport)
     {
         _restoreViewSupport = restoreViewSupport;
     }
 
     public PhaseId getPhase()
     {
         return PhaseId.RESTORE_VIEW;
     }
     
     protected boolean checkViewNotFound(FacesContext facesContext)
     {
         if (_viewNotFoundCheck == null)
         {
             
             _viewNotFoundCheck = MyfacesConfig.getCurrentInstance(
                 facesContext.getExternalContext()).isStrictJsf2ViewNotFound();
         }
         return _viewNotFoundCheck;
     }
     
     private void sendSourceNotFound(FacesContext context, String message)
     {
         HttpServletResponse response = (HttpServletResponse) context.getExternalContext().getResponse();
         try
         {
             context.responseComplete();
             response.sendError(HttpServletResponse.SC_NOT_FOUND, message);
         }
         catch (IOException ioe)
         {
             throw new FacesException(ioe);
         }
     }
 }