/**
    * Copyright 2005-2013 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.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.web.controller;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.log4j.Logger;
  import org.kuali.rice.krad.service.KRADServiceLocator;
  import org.kuali.rice.krad.service.KRADServiceLocatorWeb;
  import org.kuali.rice.krad.uif.UifConstants;
  import org.kuali.rice.krad.uif.UifParameters;
  import org.kuali.rice.krad.uif.util.ComponentFactory;
  import org.kuali.rice.krad.uif.view.History;
  import org.kuali.rice.krad.uif.view.HistoryEntry;
  import org.kuali.rice.krad.uif.view.View;
  import org.kuali.rice.krad.uif.component.Component;
  import org.kuali.rice.krad.uif.service.ViewService;
  import org.kuali.rice.krad.util.KRADConstants;
  import org.kuali.rice.krad.util.KRADUtils;
  import org.kuali.rice.krad.web.form.UifFormBase;
  import org.kuali.rice.krad.web.form.UifFormManager;
  import org.springframework.web.servlet.ModelAndView;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * 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 UifControllerHelper {
      private static final Logger LOG = Logger.getLogger(UifControllerHelper.class);
  
      /**
       * 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 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 pageId) {
          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;
      }
  
      /**
       * 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)) {
              return;
          }
          UifControllerBase controller = (UifControllerBase) handler;
  
          Object model = modelAndView.getModelMap().get(UifConstants.DEFAULT_MODEL_NAME);
          if (!(model instanceof UifFormBase)) {
              return;
          }
          UifFormBase form = (UifFormBase) model;
  
          // handle view building if not a redirect
          if (!form.isRequestRedirected()) {
              // prepare view instance
              prepareViewForRendering(request, form);
  
              // for component, page refresh and dialog update need to export the component as a model
             Component component = null;
             if (form.isUpdateComponentRequest() || form.isUpdateDialogRequest()) {
                 component = form.getPostedView().getViewIndex().getComponentById(form.getUpdateComponentId());
             } else if (form.isUpdatePageRequest()) {
                 component = form.getView().getCurrentPage();
             }
 
             if (component != null) {
                 modelAndView.addObject(UifConstants.COMPONENT_MODEL_NAME, component);
             }
 
             // update history for view
             prepareHistory(request, form);
         }
 
         // expose additional objects to the templates
         modelAndView.addObject(UifParameters.REQUEST, request);
         modelAndView.addObject(KRADConstants.USER_SESSION_KEY, request.getSession().getAttribute(
                 KRADConstants.USER_SESSION_KEY));
 
         Map<String, String> properties = KRADServiceLocator.getKualiConfigurationService().getAllProperties();
         modelAndView.addObject(UifParameters.CONFIG_PROPERTIES, properties);
     }
 
     /**
      * 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();
 
             processReturnLocationOverride(form);
 
             history.setHomewardPath(view.getBreadcrumbs().getHomewardPathList());
             history.setAppendHomewardPath(view.getBreadcrumbs().isDisplayHomewardPath());
 
             // 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)));
             }
 
             // do not append the history for dialog boxes
             if (form.getDialogManager().getDialogs().size() > 0) {
                 history.setAppendPassedHistory(false);
             } else if (StringUtils.isNotBlank(request.getParameter(UifConstants.UrlParams.SHOW_HISTORY))) {
                 history.setAppendPassedHistory(Boolean.parseBoolean(request.getParameter(
                         UifConstants.UrlParams.SHOW_HISTORY)));
             } else {
                 history.setAppendPassedHistory(view.getBreadcrumbs().isDisplayPassedHistory());
             }
 
             history.buildCurrentEntryFromRequest(form, request);
             history.buildHistoryFromParameterString(request.getParameter(UifConstants.UrlParams.HISTORY));
 
             form.setFormHistory(history);
         }
     }
 
     /**
      * Checks for the return location parameter and overrides the homeward path if necesssary
      *
      * @param form form instance that contains the view and return location
      */
     protected static void processReturnLocationOverride(UifFormBase form) {
         View view = form.getView();
 
         if (form.getReturnLocation() == null) {
             return;
         }
 
         List<HistoryEntry> homewardPathList = new ArrayList<HistoryEntry>();
         if ((view != null) && (view.getBreadcrumbs() != null) &&
                 (view.getBreadcrumbs().getHomewardPathList() != null)) {
             homewardPathList = view.getBreadcrumbs().getHomewardPathList();
         }
 
         HistoryEntry historyEntry = new HistoryEntry("", "", "Home", form.getReturnLocation(), "");
         if (homewardPathList.isEmpty()) {
             homewardPathList.add(historyEntry);
         } else if (StringUtils.equals(homewardPathList.get(0).getTitle(), "Home")) {
             homewardPathList.set(0, historyEntry);
         } else {
             homewardPathList.add(0, historyEntry);
         }
     }
 
     /**
      * Prepares the <code>View</code> instance contained on the form for rendering
      *
      * @param request - request object
      * @param form - form instance containing the data and view instance
      */
     public static void prepareViewForRendering(HttpServletRequest request, UifFormBase form) {
         // for component refreshes only lifecycle for component is performed
         if (form.isUpdateComponentRequest() || form.isUpdateDialogRequest()) {
             String refreshComponentId = form.getUpdateComponentId();
 
             // get a new instance of the component
             Component comp = ComponentFactory.getNewInstanceForRefresh(form.getPostedView(), refreshComponentId);
 
             View postedView = form.getPostedView();
 
             // run lifecycle and update in view
             postedView.getViewHelperService().performComponentLifecycle(postedView, form, comp, refreshComponentId);
 
             // regenerate server message content for page
             postedView.getCurrentPage().getValidationMessages().generateMessages(false, postedView, form,
                     postedView.getCurrentPage());
         } else {
             // full view build
             View view = form.getView();
 
             // set view page to page requested on form
             if (StringUtils.isNotBlank(form.getPageId())) {
                 view.setCurrentPageId(form.getPageId());
             }
 
             Map<String, String> parameterMap = KRADUtils.translateRequestParameterMap(request.getParameterMap());
             parameterMap.putAll(form.getViewRequestParameters());
 
             // build view which will prepare for rendering
             getViewService().buildView(view, form, parameterMap);
         }
     }
 
     /**
      * Remove unused forms from breadcrumb history
      *
      * <p>
      * When going back in the breadcrumb history some forms become unused in the breadcrumb history.  Here the unused
      * forms are being determine and removed from the server to free memory.
      * </p>
      *
      * @param uifFormManager
      * @param formKey of the current form
      * @param lastFormKey of the last form
      */
     public static void removeUnusedBreadcrumbs(UifFormManager uifFormManager, String formKey, String lastFormKey) {
         if (StringUtils.isBlank(formKey) || StringUtils.isBlank(lastFormKey) || StringUtils.equals(formKey,
                 lastFormKey)) {
             return;
         }
 
         UifFormBase previousForm = uifFormManager.getSessionForm(lastFormKey);
         if (previousForm == null) {
             return;
         }
 
         boolean cleanUpRemainingForms = false;
         for (HistoryEntry historyEntry : previousForm.getFormHistory().getHistoryEntries()) {
             if (cleanUpRemainingForms) {
                 uifFormManager.removeSessionFormByKey(historyEntry.getFormKey());
             } else {
                 if (StringUtils.equals(formKey, historyEntry.getFormKey())) {
                     cleanUpRemainingForms = true;
                 }
             }
         }
 
         uifFormManager.removeSessionFormByKey(lastFormKey);
     }
 
     protected static ViewService getViewService() {
         return KRADServiceLocatorWeb.getViewService();
     }
 }