/**
    * 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.core.api.CoreApiServiceLocator;
  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.util.ComponentUtils;
  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.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);
  
      /**
       * Attempts to resolve a view id from the given request
       *
       * <p>
       * First an attempt will be made to find the view id as a request parameter. If no such request parameter
       * is found, the request will be looked at for view type information and a call will be made to the
       * view service to find the view id by type
       * </p>
       *
       * <p>
       * If a view id is found it is stuck in the request as an attribute (under the key
       * {@link org.kuali.rice.krad.uif.UifParameters#VIEW_ID}) for subsequent retrieval
       * </p>
       *
       * @param request instance to resolve view id for
       * @return view id if one is found, null if not found
       */
      public static String getViewIdFromRequest(HttpServletRequest request) {
          String viewId = request.getParameter(UifParameters.VIEW_ID);
  
          if (StringUtils.isBlank(viewId)) {
              String viewTypeName = request.getParameter(UifParameters.VIEW_TYPE_NAME);
  
              UifConstants.ViewType viewType = null;
              if (StringUtils.isNotBlank(viewTypeName)) {
                  viewType = UifConstants.ViewType.valueOf(viewTypeName);
              }
  
              if (viewType != null) {
                  Map<String, String> parameterMap = KRADUtils.translateRequestParameterMap(request.getParameterMap());
                  viewId = getViewService().getViewIdForViewType(viewType, parameterMap);
              }
          }
  
          if (StringUtils.isNotBlank(viewId)) {
             request.setAttribute(UifParameters.VIEW_ID, viewId);
          }
  
          return viewId;
      }
  
      /**
       * 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 (modelAndView == null) {
             return;
         }
 
         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);
             }
         }
 
         // 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 = CoreApiServiceLocator.getKualiConfigurationService().getAllProperties();
         modelAndView.addObject(UifParameters.CONFIG_PROPERTIES, properties);
     }
 
     /**
      * 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();
 
             View postedView = form.getPostedView();
 
             // check if the component is nested in a box layout in order to reapply the layout item style
             boolean boxLayoutHorizontalItem = false;
             boolean boxLayoutVerticalItem = false;
 
             if (form.isUpdateComponentRequest()) {
                 Component postedComponent = ComponentUtils.findNestedComponentById(postedView, refreshComponentId);
                 if (postedComponent != null && postedComponent.getCssClasses() != null &&
                         postedComponent.getCssClasses().contains("uif-boxLayoutHorizontalItem")) {
                     boxLayoutHorizontalItem = true;
                 } else if (postedComponent != null && postedComponent.getCssClasses() != null &&
                         postedComponent.getCssClasses().contains("uif-boxLayoutVerticalItem")) {
                     boxLayoutVerticalItem = true;
                 }
             }
 
             // get a new instance of the component
             Component comp = ComponentFactory.getNewInstanceForRefresh(form.getPostedView(), refreshComponentId);
 
             // run lifecycle and update in view
             postedView.getViewHelperService().performComponentLifecycle(postedView, form, comp, refreshComponentId);
 
             // add the layout item style that should happen in the parent BoxLayoutManager
             // and is skipped in a child component refresh
             if (boxLayoutHorizontalItem) {
                 comp.addStyleClass("uif-boxLayoutHorizontalItem");
             } else if (boxLayoutVerticalItem) {
                 comp.addStyleClass("uif-boxLayoutVerticalItem");
             }
 
             // 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;
         }
 
         uifFormManager.removeSessionFormByKey(lastFormKey);
     }
 
     protected static ViewService getViewService() {
         return KRADServiceLocatorWeb.getViewService();
     }
 }