/**

  * Copyright 2010 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.osedu.org/licenses/ECL-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.kuali.student.common.ui.client.mvc;

 import java.util.ArrayList;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.Map;

 import org.kuali.student.common.assembly.data.Data;

 import org.kuali.student.common.rice.authorization.PermissionType;

 import org.kuali.student.common.ui.client.application.KSAsyncCallback;

 import org.kuali.student.common.ui.client.application.ViewContext;

 import org.kuali.student.common.ui.client.configurable.mvc.LayoutController;

 import org.kuali.student.common.ui.client.configurable.mvc.views.SectionView;

 import org.kuali.student.common.ui.client.mvc.breadcrumb.BreadcrumbSupport;

 import org.kuali.student.common.ui.client.mvc.history.HistoryManager;

 import org.kuali.student.common.ui.client.mvc.history.HistorySupport;

 import org.kuali.student.common.ui.client.mvc.history.NavigationEvent;

 import org.kuali.student.common.ui.client.reporting.ReportExport;

 import org.kuali.student.common.ui.client.security.AuthorizationCallback;

 import org.kuali.student.common.ui.client.security.RequiresAuthorization;

 import org.kuali.student.common.ui.client.service.GwtExportRpcService;

 import org.kuali.student.common.ui.client.service.GwtExportRpcServiceAsync;

 import org.kuali.student.common.ui.client.util.ExportElement;

 import org.kuali.student.common.ui.client.util.ExportUtils;

 import org.kuali.student.common.ui.client.widgets.progress.BlockingTask;

 import org.kuali.student.common.ui.client.widgets.progress.KSBlockingProgressIndicator;

 import com.google.gwt.core.client.GWT;

 import com.google.gwt.event.shared.GwtEvent.Type;

 import com.google.gwt.event.shared.HandlerManager;

 import com.google.gwt.event.shared.HandlerRegistration;

 import com.google.gwt.user.client.Window;

 import com.google.gwt.user.client.ui.Composite;

 import com.google.gwt.user.client.ui.Widget;

 /**

  * Abstract Controller composite. Provides basic controller operations, and defines abstract methods that a composite must

  * implement in order to be a controller.

  * 

  * @author Kuali Student Team

  */

 public abstract class Controller extends Composite implements HistorySupport, BreadcrumbSupport, ReportExport{

         public static final Callback<Boolean> NO_OP_CALLBACK = new Callback<Boolean>() {

                 @Override

                 public void exec(Boolean result) {

                         // do nothing

                 }

         };

     protected Controller parentController = null;

     private View currentView = null;

     private Enum<?> currentViewEnum = null;

     private String defaultModelId = null;

     protected ViewContext context = new ViewContext();

     private final Map<String, ModelProvider<? extends Model>> models = new HashMap<String, ModelProvider<? extends Model>>();

     private boolean fireNavEvents = true;

     private HandlerManager applicationEventHandlers = new HandlerManager(this);

     private GwtExportRpcServiceAsync reportExportRpcService = GWT.create(GwtExportRpcService.class);

     protected Controller() {

     }

     /**

      * Simple Version of showView, no callback

      * @param <V>

      *                         view enum type

      * @param viewType

      *                         enum value representing the view to show

      */

     public <V extends Enum<?>> void showView(final V viewType){

             this.showView(viewType, NO_OP_CALLBACK);

     }

     /**

      * Directs the controller to display the specified view. The parameter must be an enum value, based on an enum defined in

      * the controller implementation. For example, a "Search" controller might have an enumeration of: <code>

      *  public enum SearchViews {

      *      SIMPLE_SEARCH,

      *      ADVANCED_SEARCH,

      *      SEARCH_RESULTS

      *  }

      * </code> The implementing class must define a getView(V viewType) method that will cast the generic enum to the view

      * specific enum.

      * 

      * @param <V>

      *            view enum type

      * @param viewType

      *            enum value representing the view to show

      * @param onReadyCallback the callback to invoke when the method has completed execution

      * @return false if the current view cancels the operation

      */

     public <V extends Enum<?>> void showView(final V viewType, final Callback<Boolean> onReadyCallback) {

         GWT.log("showView " + viewType.toString(), null);

         getView(viewType, new Callback<View>(){

                         @Override

                         public void exec(View result) {

                                 View view = result;

                                 if (view == null) {

                                 onReadyCallback.exec(false);

                             //throw new ControllerException("View not registered: " + viewType.toString());

                         }

                         beginShowView(view, viewType, onReadyCallback);

                         }});

     }

     private <V extends Enum<?>> void beginShowView(final View view, final V viewType, final Callback<Boolean> onReadyCallback){

             beforeViewChange(viewType, new Callback<Boolean>(){

                         @Override

                         public void exec(Boolean result) {

                                 if(result){

                                          boolean requiresAuthz = (view instanceof RequiresAuthorization) && ((RequiresAuthorization)view).isAuthorizationRequired(); 

                                         if (requiresAuthz){

                                                 ViewContext tempContext = new ViewContext();

                                                 if(view instanceof LayoutController){

                                                         tempContext = ((LayoutController) view).getViewContext();

                                                 }                 

                                                 else{

                                                         tempContext = view.getController().getViewContext();

                                                 }

                                                 PermissionType permType = (tempContext != null) ? tempContext.getPermissionType() : null;

                                                 if (permType != null) {

                                                         GWT.log("Checking permission type '" + permType.getPermissionTemplateName() + "' for view '" + view.toString() + "'", null);

                                                     //A callback is required if async rpc call is required for authz check

                                                         ((RequiresAuthorization)view).checkAuthorization(permType, new AuthorizationCallback(){

                                                                         public void isAuthorized() {

                                                                                 finalizeShowView(view, viewType, onReadyCallback);

                                                                         }

                                                                         public void isNotAuthorized(String msg) {

                                                                                 Window.alert(msg);

                                                                                 onReadyCallback.exec(false);                                        

                                                                         }                        

                                                         });

                                                 }

                                                 else {

                                                         GWT.log("Cannot find PermissionType for view '" + view.toString() + "' which requires authorization", null);

                                                     finalizeShowView(view, viewType, onReadyCallback);

                                                 }

                                         } else {

                                                     GWT.log("Not Requiring Auth.", null);

                                                 finalizeShowView(view, viewType, onReadyCallback);

                                         }

                                 }

                                 else{

                                         onReadyCallback.exec(false);

                                 }

                         }

                 });

     }

     private <V extends Enum<?>> void finalizeShowView(final View view, final V viewType, final Callback<Boolean> onReadyCallback){

         if ((currentView == null) || currentView.beforeHide()) {

                         view.beforeShow(new Callback<Boolean>() {

                                 @Override

                                 public void exec(Boolean result) {

                                         if (!result) {

                                                 GWT.log("showView: beforeShow yielded false " + viewType, null);

                                         onReadyCallback.exec(false);

                                         } else {

                                         if (currentView != null) {

                                         hideView(currentView);

                                     }

                                     currentViewEnum = viewType;

                                     currentView = view;

                                     GWT.log("renderView " + viewType.toString(), null);

                                     if(fireNavEvents){

                                             fireNavigationEvent();

                                     }

                                     renderView(view);

                                         onReadyCallback.exec(true);

                                         }

                                 }

                         });

         } else {

                 onReadyCallback.exec(false);

             GWT.log("Current view canceled hide action", null);

         }            

     }

     protected void fireNavigationEvent() {

         //DeferredCommand.addCommand(new Command() {

            // @Override

             //public void execute() {

                 fireApplicationEvent(new NavigationEvent(Controller.this));

             //}

         //});

     }

     /**

      * Returns the currently displayed view

      * 

      * @return the currently displayed view

      */

     public View getCurrentView() {

         return currentView;

     }

     public Enum<?> getCurrentViewEnum() {

         return currentViewEnum;

     }

     public void setCurrentViewEnum(Enum<?> currentViewEnum) {

         this.currentViewEnum = currentViewEnum;

     }

     /**

      * Sets the controller's parent controller. In most cases, this can be omitted as the controller will be automatically

      * detected via the DOM in cases where it is not specified. The only time that the controller needs to be manually set is

      * in cases where the logical controller hierarchy differs from the physical DOM hierarchy. For example, if a nested

      * controller is rendered in a PopupPanel, then the parent controller must be set manually using this method

      * 

      * @param controller

      *            the parent controller

      */

     public void setParentController(Controller controller) {

         parentController = controller;

     }

     /**

      * Returns the parent controller. If the current parent controller is not set, then the controller will attempt to

      * automatically locate the parent controller via the DOM.

      * 

      * @return

      */

     public Controller getParentController() {

         if (parentController == null) {

             parentController = Controller.findController(this);

         }

         return parentController;

     }

     /**

      * Attempts to find the parent controller of a given widget via the DOM

      * 

      * @param w

      *            the widget for which to find the parent controller

      * @return the controller, or null if not found

      */

     public static Controller findController(Widget w) {

         Controller result = null;

         while (true) {

             w = w.getParent();

             if (w == null) {

                 break;

             } else if (w instanceof Controller) {

                 result = (Controller) w;

                 break;

             } else if (w instanceof View) {

                 // this is in the event that a parent/child relationship is broken by a view being rendered in a lightbox,

                 // etc

                 result = ((View) w).getController();

                 break;

             }

         }

         return result;

     }

     /**

      * Called by child views and controllers to request a model reference. By default it delegates calls to the parent

      * controller if one is found. Override this method to declare a model local to the controller. Always make sure to

      * delegate the call to the superclass if the requested type is not one which is defined locally. For example: <code>

      * 

      * @Override

      * @SuppressWarnings("unchecked") public void requestModel(Class<? extends Idable> modelType, ModelRequestCallback

      *                                callback) { if (modelType.equals(Address.class)) { callback.onModelReady(addresses); }

      *                                else { super.requestModel(modelType, callback); } } </code>

      * @param modelType

      * @param callback

      */

     @SuppressWarnings("unchecked")

     public void requestModel(final Class modelType, final ModelRequestCallback callback) {

         requestModel((modelType == null) ? null : modelType.getName(), callback);

     }

     @SuppressWarnings("unchecked")

     public void requestModel(final String modelId, final ModelRequestCallback callback) {

         String id = (modelId == null) ? defaultModelId : modelId;

         ModelProvider<? extends Model> p = models.get(id);

         if (p != null) {

             p.requestModel(callback);

         } else if (getParentController() != null) {

             parentController.requestModel(modelId, callback);

         } else {

             if (callback != null) {

                 callback.onRequestFail(new RuntimeException("The requested model was not found: " + modelId));

             }

         }

     }

     @SuppressWarnings("unchecked")

     public void requestModel(final ModelRequestCallback callback) {

         requestModel((String)null, callback);

     }

     public <T extends Model> void registerModel(String modelId, ModelProvider<T> provider) {

         models.put(modelId, provider);

     }

     public String getDefaultModelId() {

         return defaultModelId;

     }

     public void setDefaultModelId(String defaultModelId) {

         this.defaultModelId = defaultModelId;

     }

     /**

      * Registers an application eventhandler. The controller will try to propagate "unchecked" handlers to the parent

      * controller if a parent controller exists. This method can be overridden to handle unchecked locally if they are fired

      * locally.

      * 

      * @param type

      * @param handler

      * @return

      */

     @SuppressWarnings("unchecked")

     public HandlerRegistration addApplicationEventHandler(Type type, ApplicationEventHandler handler) {

         if ((handler instanceof UncheckedApplicationEventHandler) && (getParentController() != null)) {

             return parentController.addApplicationEventHandler(type, handler);

         }

         return applicationEventHandlers.addHandler(type, handler);

     }

     /**

      * Fires an application event.

      * 

      * @param event

      */

     @SuppressWarnings("unchecked")

     public void fireApplicationEvent(ApplicationEvent event) {

         // TODO this logic needs to be reworked a bit... if an unchecked event has been bound locally, do we want to still

         // fire it externally as well?

         if ((event instanceof UncheckedApplicationEvent) && (getParentController() != null)) {

             parentController.fireApplicationEvent(event);

         }

         // dispatch to local "checked" handlers, and to any unchecked handlers that have been bound to local

         applicationEventHandlers.fireEvent(event);

     }

     /**

      * Must be implemented by the subclass to render the view.

      * 

      * @param view

      */

     protected abstract void renderView(View view);

     /**

      * Must be implemented by the subclass to hide the view.

      * 

      * @param view

      */

     protected abstract void hideView(View view);

     /**

      * Returns the view associated with the specified enum value. See showView(V viewType) above for a full description

      * 

      * @param <V>

      * @param viewType

      * @return

      */

     protected abstract <V extends Enum<?>> void getView(V viewType, Callback<View> callback);

     /**

      * If a controller which extends this class must perform some action or check before a view

      * is changed, then override this method.  Do not call super() in the override, as it will

      * allow the view to continue to change.

      * @param okToChangeCallback

      */

     public void beforeViewChange(Enum<?> viewChangingTo, Callback<Boolean> okToChangeCallback) {

             okToChangeCallback.exec(true);

     }

     /**

      * Shows the default view. Must be implemented by subclass, in order to define the default view.

      */

     public abstract void showDefaultView(Callback<Boolean> onReadyCallback);

     public abstract Enum<?> getViewEnumValue(String enumValue);

     /**

      * This particular implementation appends to the history stack the name of the current view shown by

      * this controller and view context (in string format) to that historyStack and passes the stack to

      * be processed to the currentView.

      * @see org.kuali.student.common.ui.client.mvc.history.HistorySupport#collectHistory(java.lang.String)

      */

     @Override

     public String collectHistory(String historyStack) {

             String token = getHistoryToken();

             historyStack = historyStack + "/" + token;

             if(currentView != null){

                     String tempHistoryStack = historyStack;

                     historyStack = currentView.collectHistory(historyStack);

                     //Sanity check, if collectHistory returns null or empty string, restore

                     if(historyStack == null){

                             historyStack = tempHistoryStack;

                     }

                     else if(historyStack != null && historyStack.isEmpty()){

                             historyStack = tempHistoryStack;

                     }

             }

             return historyStack;

     }

     protected String getHistoryToken() {

             String historyToken = "";

         if (currentViewEnum != null) {

             historyToken = currentViewEnum.toString();

             if(currentView != null && currentView instanceof Controller 

                             && ((Controller)currentView).getViewContext() != null){

                     ViewContext context = ((Controller) currentView).getViewContext();

                     historyToken = HistoryManager.appendContext(historyToken, context);

             }

         }

         return historyToken;

     }

     /**

      * The onHistoryEvent implementation in controller reads the history stack it receives and determines

      * if the next token/view to be processed is a controller, if it is, it hands off the rest of the history stack

      * to that controller after showing it.  Otherwise, it shows the view

      * and allows that view to perform any onHistoryEvent actions it may need to take.

      * <br><br>For example the historyStack /HOME/CURRICULUM_HOME/COURSE_PROPOSAL would start at the root controller,

      * and hand it off to the home controller, then the curriculum home controller, then the course proposal controller

      * and stop there.  Along the way each of those controller would show themselves visually in the UI, 

      * if they contain any layout (some do not).

      * 

      * @see org.kuali.student.common.ui.client.mvc.history.HistorySupport#onHistoryEvent(java.lang.String)

      */

     @Override

     public void onHistoryEvent(String historyStack) {

             final String nextHistoryStack = HistoryManager.nextHistoryStack(historyStack);

         String[] tokens = HistoryManager.splitHistoryStack(nextHistoryStack);

         if (tokens.length >= 1 && tokens[0] != null && !tokens[0].isEmpty()) {

             final Map<String, String> tokenMap = HistoryManager.getTokenMap(tokens[0]);

             //TODO add some automatic view context setting here, get and set

             String viewEnumString = tokenMap.get("view");

             if (viewEnumString != null) {

                 final Enum<?> viewEnum = getViewEnumValue(viewEnumString);

                 if (viewEnum != null) {

                         getView(viewEnum, new Callback<View>(){

                                                 @Override

                                                 public void exec(View result) {

                                                         View theView = result;

                                             boolean sameContext = true;

                                         if(theView instanceof Controller){

                                                 ViewContext newContext = new ViewContext();

                                                 Iterator<String> tokenIt = tokenMap.keySet().iterator();

                                                 while(tokenIt.hasNext()){

                                                         String key = tokenIt.next();

                                                         if(key.equals(ViewContext.ID_ATR)){

                                                                 newContext.setId(tokenMap.get(ViewContext.ID_ATR));

                                                         }

                                                         else if(key.equals(ViewContext.ID_TYPE_ATR)){

                                                                 newContext.setIdType(tokenMap.get(ViewContext.ID_TYPE_ATR));

                                                         }

                                                         //do not add view attribute from the token map to the context

                                                         else if(!key.equals("view")){

                                                                 newContext.setAttribute(key, tokenMap.get(key));

                                                         }

                                                 }

                                                 ViewContext viewContext = ((Controller) theView).getViewContext();

                                                 if(viewContext.compareTo(newContext) != 0){

                                                         ((Controller) theView).setViewContext(newContext);

                                                         sameContext = false;

                                                 }

                                         }

                                     if (currentViewEnum == null || !viewEnum.equals(currentViewEnum) 

                                                     || !sameContext) {

                                         beginShowView(theView, viewEnum, new Callback<Boolean>() {

                                             @Override

                                             public void exec(Boolean result) {

                                                 if (result) {

                                                     currentView.onHistoryEvent(nextHistoryStack);

                                                 }

                                             }

                                         });

                                     } else if (currentView != null) {

                                             currentView.onHistoryEvent(nextHistoryStack);

                                     }

                                                 }

                                         });

                 }

             }

         }

         else{

                     this.showDefaultView(new Callback<Boolean>(){

                                 @Override

                                 public void exec(Boolean result) {

                                         if(result){

                                                 currentView.onHistoryEvent(nextHistoryStack);

                                         }

                                 }

                         });

             }

     }

     /**

      * Sets the view context.  This is important for determining the permission for seeing views under

      * this controllers scope, what the id and id type of the model the controller handles are defined here.

      * Additional attributes that the controller and it's views need to know about are also defined in the

      * viewContext.

      * @param viewContext

      */

     public void setViewContext(ViewContext viewContext){

             this.context = viewContext;

     }

     public ViewContext getViewContext() {

             return this.context;

     }

     public void resetCurrentView(){

             currentView = null;

     }

     /**

      * 

      * This method implement the "Generic Export" of a windows content to Jasper based on the format the user selected.

      * This method can be overwritten on a subclass to do specific export to the specific view

      * 

      * @see org.kuali.student.common.ui.client.reporting.ReportExport#doReportExport(java.util.ArrayList)

      */

     @Override

     public void doReportExport(ArrayList<ExportElement> exportElements, final String format, final String reportTitle) {        

      // Service call...

             final BlockingTask loadDataTask = new BlockingTask("Generating Export File");

         DataModel dataModel = getExportDataModel();

         Data modelDataObject = null;

         if (dataModel != null) {

             modelDataObject = dataModel.getRoot();

         }   

         // we want to show that something is happening while the files are generated.

         KSBlockingProgressIndicator.addTask(loadDataTask);

         reportExportRpcService.reportExport(exportElements, modelDataObject, getExportTemplateName(), format, reportTitle, new KSAsyncCallback<String>() {

                     @Override

                     public void onSuccess(String result) {

                         // On success get documentID back from GWT Servlet//

                             // We need to get the base url and strip the gwt module name . 

                             String baseUrl = GWT.getHostPageBaseURL();

                             baseUrl = baseUrl.replaceFirst(GWT.getModuleName() + "/", "");                                                

                             KSBlockingProgressIndicator.removeTask(loadDataTask);

                         Window.open(baseUrl + "exportDownloadHTTPServlet?exportId="+result + "&format=" + format, "", "");                          

                     }

                                         @Override

                                         public void handleFailure(Throwable caught) {

                                                 KSBlockingProgressIndicator.removeTask(loadDataTask);

                                                 super.handleFailure(caught);

                                         }                                                    

                 });

     }

     // TODO Nina ??? Do we want to keep this seen in the light of the exportElements parameter

     @Override

     public DataModel getExportDataModel() {

         return null;

     }

     /**

      * 

      * @see org.kuali.student.common.ui.client.reporting.ReportExport#getExportTemplateName()

      */

     @Override

     public String getExportTemplateName() {

         return exportTemplateName;

     }

     @Override

     public ArrayList<ExportElement> getExportElementsFromView() {

         String viewName = null;

         View currentView = this.getCurrentView();

         if (currentView != null) {

             ArrayList<ExportElement> exportElements = null;

             if (currentView != null && currentView instanceof SectionView) {

                 viewName =  currentView.getName();

                 exportElements = ExportUtils.getExportElementsFromView((SectionView)currentView, exportElements, viewName, "Sectionname");

                 return exportElements;

             } else {

 //                logger.warn("ExportUtils.getExportElementsFromView not implemented for :" + this.getCurrentView());

             }

         } else {

 //            logger.warn("ExportUtils.getExportElementsFromView controller currentView is null :" + this.getClass().getName());

         }

         return null;

     }

 }