/*
    * 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();
     }
 }