/*

  * Copyright 2011 The Kuali Foundation Licensed under the Educational Community

  * License, Version 1.0 (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.opensource.org/licenses/ecl1.php 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.kuali.rice.krad.uif.util;

 import org.apache.commons.lang.StringUtils;

 import org.apache.log4j.Logger;

 import org.kuali.rice.krad.UserSession;

 import org.kuali.rice.krad.service.KRADServiceLocatorWeb;

 import org.kuali.rice.krad.service.SessionDocumentService;

 import org.kuali.rice.krad.uif.UifConstants;

 import org.kuali.rice.krad.uif.UifParameters;

 import org.kuali.rice.krad.uif.container.View;

 import org.kuali.rice.krad.uif.core.Component;

 import org.kuali.rice.krad.uif.history.History;

 import org.kuali.rice.krad.uif.service.ViewService;

 import org.kuali.rice.krad.util.KRADConstants;

 import org.kuali.rice.krad.web.controller.UifControllerBase;

 import org.kuali.rice.krad.web.form.DocumentFormBase;

 import org.kuali.rice.krad.web.form.UifFormBase;

 import org.springframework.web.servlet.ModelAndView;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 /**

  * Provides helper methods that will be used during the request lifecycle

  *

  * <p>

  * Created to avoid duplication of the methods used by the UifHandlerExceptionResolver

  * </p>

  *

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public class UifWebUtils {

     private static final Logger LOG = Logger.getLogger(UifWebUtils.class);

     /**

      * Gets the form from the request

      *

      * <p>

      * Looks for the form on the session by using the form key. If the form is not

      * on the session it will attempt to get it from the database.

      * </p>

      *

      * @param request the http request

      * @return the form from request

      */

     public static UifFormBase getFormFromRequest(HttpServletRequest request) {

         UifFormBase form = null;

         String formKeyParam = request.getParameter(UifParameters.FORM_KEY);

         String docId = request.getParameter(KRADConstants.DOCUMENT_DOCUMENT_NUMBER);

         if (StringUtils.isNotBlank(formKeyParam)) {

             form = (UifFormBase) request.getSession().getAttribute(formKeyParam);

             // retreive from db if form not in session

             if (form == null) {

                 UserSession userSession =

                         (UserSession) request.getSession().getAttribute(KRADConstants.USER_SESSION_KEY);

                 form = KRADServiceLocatorWeb.getSessionDocumentService()

                         .getDocumentForm(docId, formKeyParam, userSession, request.getRemoteAddr());

             }

         }

         return form;

     }

     /**

      * Configures the <code>ModelAndView</code> instance containing the form

      * data and pointing to the UIF generic spring view

      *

      * @param form - Form instance containing the model data

      * @param viewId - Id of the View to return

      * @param pageId - Id of the page within the view that should be rendered, can

      * be left blank in which the current or default page is rendered

      * @return ModelAndView object with the contained form

      */

     public static ModelAndView getUIFModelAndView(UifFormBase form, String viewId, String pageId) {

         // update form with the requested view id and page

         form.setViewId(viewId);

         if (StringUtils.isNotBlank(pageId)) {

             form.setPageId(pageId);

         }

         // create the spring return object pointing to View.jsp

         ModelAndView modelAndView = new ModelAndView();

         modelAndView.addObject(UifConstants.DEFAULT_MODEL_NAME, form);

         modelAndView.setViewName(UifConstants.SPRING_VIEW_ID);

         return modelAndView;

     }

     public static ModelAndView getComponentModelAndView(Component component, Object model) {

         ModelAndView modelAndView = new ModelAndView();

         modelAndView.addObject(UifConstants.DEFAULT_MODEL_NAME, model);

         modelAndView.addObject("Component", component);

         modelAndView.setViewName("ComponentUpdate");

         return modelAndView;

     }

     /**

      * After the controller logic is executed, the form is placed into session

      * and the corresponding view is prepared for rendering

      */

     public static void postControllerHandle(HttpServletRequest request, HttpServletResponse response, Object handler,

             ModelAndView modelAndView) throws Exception {

         if (handler instanceof UifControllerBase && (modelAndView != null)) {

             UifControllerBase controller = (UifControllerBase) handler;

             UifFormBase form = null;

             // check to see if this is a full view request

             if (modelAndView.getViewName().equals(UifConstants.SPRING_VIEW_ID)) {

                 Object model = modelAndView.getModelMap().get(UifConstants.DEFAULT_MODEL_NAME);

                 if (model instanceof UifFormBase) {

                     form = (UifFormBase) model;

                     form.setPreviousView(null);

                     // update history for view

                     prepareHistory(request, form);

                     // store form to session and persist document form to db as well

                     request.getSession().setAttribute(form.getFormKey(), model);

                     if (form instanceof DocumentFormBase) {

                         UserSession userSession =

                                 (UserSession) request.getSession().getAttribute(KRADConstants.USER_SESSION_KEY);

                         getSessionDocumentService()

                                 .setDocumentForm((DocumentFormBase) form, userSession, request.getRemoteAddr());

                     }

                     // perform authorization of controller method

                     checkMethodToCallAuthorization(request, controller, form);

                     // prepare view contained in form

                     prepareViewForRendering(form);

                 }

             }

         }

     }

     /**

      * Verify the user is authorized to invoke the controller method according

      * to the module that owns the functionality. This is done post handle to be

      * able to access the form and whatever processing was done TODO: should

      * this be throwing some exception?

      *

      * @param request - current HTTP request containing method to call parameter

      * @param controller - controller that was invoked

      * @param form - form instance containing the data

      */

     public static void checkMethodToCallAuthorization(HttpServletRequest request, UifControllerBase controller,

             UifFormBase form) {

         // currently methodToCall must be a regularly parseable request

         // parameter, so just get from request

         String methodToCall = request.getParameter(KRADConstants.DISPATCH_REQUEST_PARAMETER);

         if (!controller.getMethodToCallsToNotCheckAuthorization().contains(methodToCall)) {

             if (LOG.isDebugEnabled()) {

                 LOG.debug("'" + methodToCall + "' not in set of excempt methods: " +

                         controller.getMethodToCallsToNotCheckAuthorization());

             }

             controller.checkAuthorization(form, methodToCall);

         } else {

             if (LOG.isDebugEnabled()) {

                 LOG.debug("'" + methodToCall + "' is exempt from auth checks.");

             }

         }

     }

     /**

      * Updates the history object (or constructs a new History) for the view we are getting ready

      * to render

      *

      * @param request - Http request object containing the request parameters

      * @param form - object containing the view data

      */

     public static void prepareHistory(HttpServletRequest request, UifFormBase form) {

         View view = form.getView();

         // main history/breadcrumb tracking support

         History history = form.getFormHistory();

         if (history == null || request.getMethod().equals("GET")) {

             history = new History();

             history.setHomewardPath(view.getBreadcrumbs().getHomewardPathList());

             history.setAppendHomewardPath(view.getBreadcrumbs().isDisplayHomewardPath());

             history.setAppendPassedHistory(view.getBreadcrumbs().isDisplayPassedHistory());

             // passed settings ALWAYS override the defaults

             if (StringUtils.isNotBlank(request.getParameter(UifConstants.UrlParams.SHOW_HOME))) {

                 history.setAppendHomewardPath(

                         Boolean.parseBoolean(request.getParameter(UifConstants.UrlParams.SHOW_HOME)));

             }

             if (StringUtils.isNotBlank(request.getParameter(UifConstants.UrlParams.SHOW_HISTORY))) {

                 history.setAppendPassedHistory(

                         Boolean.parseBoolean(request.getParameter(UifConstants.UrlParams.SHOW_HISTORY)));

             }

             history.setCurrent(form, request);

             history.buildHistoryFromParameterString(request.getParameter(UifConstants.UrlParams.HISTORY));

             form.setFormHistory(history);

         }

     }

     /**

      * Prepares the <code>View</code> instance contained on the form for

      * rendering

      *

      * <p>

      * First a check is made to verify the view instance contained on the form

      * has the same id as the view id on the form (id that was requested), if

      * not a new view instance is retrieved for that view id. Then a check on

      * the view status is made to determine if we need to run the full view

      * life-cycle (in the case of a finalized view), or just the build steps

      * (apply model and finalize). Finally the page is set on the view to

      * reflect the page that was requested

      * </p>

      *

      * @param form - form instance containing the data and view instance

      */

     public static void prepareViewForRendering(UifFormBase form) {

         // if we don't have the view instance or a different view was

         // requested get new instance from the view service

         View view = form.getView();

         String viewId = form.getViewId();

         if ((view == null) || !StringUtils.equals(viewId, view.getId())) {

             if (LOG.isDebugEnabled()) {

                 LOG.debug("Getting new view instance for view id: " + viewId);

             }

             view = getViewService().getView(viewId, form.getViewRequestParameters());

             // view changed so force full render

             form.setRenderFullView(true);

         }

         // if view status is final we need to rebuild (build fresh)

         if (StringUtils.equals(UifConstants.ViewStatus.FINAL, view.getViewStatus())) {

             if (LOG.isDebugEnabled()) {

                 LOG.debug("Rebuilding view due to final status, view id: " + viewId);

             }

             view = getViewService().rebuildView(viewId, form, form.getViewRequestParameters());

         } else {

             // update the view with the model data

             getViewService().buildView(view, form);

         }

         // set dirty flag

         form.setValidateDirty(view.isValidateDirty());

         // set view page to page requested on form

         if (StringUtils.isNotBlank(form.getPageId())) {

             view.setCurrentPageId(form.getPageId());

         }

     }

     protected static SessionDocumentService getSessionDocumentService() {

         return KRADServiceLocatorWeb.getSessionDocumentService();

     }

     protected static ViewService getViewService() {

         return KRADServiceLocatorWeb.getViewService();

     }

 }