package org.kuali.student.lum.lu.ui.course.client.requirements;
   
   import org.kuali.student.common.ui.client.configurable.mvc.layouts.BasicLayout;
   import org.kuali.student.common.ui.client.configurable.mvc.views.SectionView;
   import org.kuali.student.common.ui.client.mvc.Callback;
   import org.kuali.student.common.ui.client.mvc.Controller;
   import org.kuali.student.common.ui.client.mvc.DataModel;
   import org.kuali.student.common.ui.client.mvc.ModelProvider;
   import org.kuali.student.common.ui.client.mvc.ModelRequestCallback;
  import org.kuali.student.common.ui.client.widgets.buttongroups.ButtonEnumerations;
  import org.kuali.student.common.ui.client.widgets.dialog.ButtonMessageDialog;
  import org.kuali.student.common.ui.client.widgets.field.layout.button.ButtonGroup;
  import org.kuali.student.common.ui.client.widgets.field.layout.button.YesNoCancelGroup;
  
  import com.google.gwt.core.client.GWT;
  
  public class CourseRequirementsViewController extends BasicLayout {
  
      public enum CourseRequirementsViews {
          PREVIEW,
          MANAGE
      }
  
      public static final String COURSE_RULES_MODEL_ID = "courseRulesModelId";
      public static final String COURSE_PROPOSAL_MODEL = "courseProposalModel";    
  
      private CourseRequirementsSummaryView preview;
  
      public CourseRequirementsViewController(Controller controller, String name, Enum<?> viewType, boolean isReadOnly, boolean showSaveButtons) {
  		super(CourseRequirementsViewController.class.getName());
  		super.setController(controller);
  		super.setName(name);
  		super.setViewEnum(viewType);
          super.setDefaultModelId(COURSE_RULES_MODEL_ID);
          super.setParentController(controller);
  
  		this.setDefaultView(CourseRequirementsViews.PREVIEW);
  
          //not used
          super.registerModel(COURSE_RULES_MODEL_ID, new ModelProvider<DataModel>() {
              @Override
              public void requestModel(final ModelRequestCallback<DataModel> callback) {
                  callback.onModelReady(new DataModel());
              }
          });
  
          //no name for the view so that breadcrumbs do not extra link
          preview = GWT.create(CourseRequirementsSummaryView.class);
          preview.init(
                  this,
                  CourseRequirementsViews.PREVIEW,
                  (isReadOnly ? "Course Requirements" : ""),
                  COURSE_PROPOSAL_MODEL,
                  (controller instanceof HasRequirements ? ((HasRequirements) controller).getReqDataModel()
                          : new CourseRequirementsDataModel(this)),
                  isReadOnly, showSaveButtons);
          super.addView(preview);
  
          if (!isReadOnly) {
              CourseRequirementsManageView manageView = GWT.create(CourseRequirementsManageView.class);
              manageView.init(this, CourseRequirementsViews.MANAGE, "Add and Combine Rules", COURSE_RULES_MODEL_ID);
              super.addView(manageView);
          }
      }
  
      @Override
      public void updateModel() {
          preview.updateModel();    
      }
  
      @Override
      public void beforeViewChange(final Enum<?> viewChangingTo, final Callback<Boolean> okToChange) {
  
          if (getCurrentView() == null) {
              okToChange.exec(true);
              return;
          }
  
          super.beforeViewChange(viewChangingTo, new Callback<Boolean>() {
  
              @Override
              public void exec(Boolean result) {
  
                  //no dialog if user clicks on the 'Save' button on Manage Rule page
                  if (getCurrentView() instanceof CourseRequirementsManageView) {
                      okToChange.exec(true);
                      return;
                  }
  
                  //no dialog if user is going to the Manage Rule page
                  if (viewChangingTo.name().equals(CourseRequirementsViewController.CourseRequirementsViews.MANAGE.name()))
                  {
                      //TODO show dialog if user clicks on a menu from Manage Rules page
                      okToChange.exec(true);
                      return;
                  }
  
                  //user is moving to another course proposal section and no changes were made to the rules so allow it to happen
                  if (!((SectionView) getCurrentView()).isDirty()) {
                     okToChange.exec(true);
                     return;
                 }
 
                 //user is moving to another course proposal section and rules have been changed, user needs to either save rules or abondon changes before proceeding
                 ButtonGroup<ButtonEnumerations.YesNoCancelEnum> buttonGroup = new YesNoCancelGroup();
                 final ButtonMessageDialog<ButtonEnumerations.YesNoCancelEnum> dialog =
                         new ButtonMessageDialog<ButtonEnumerations.YesNoCancelEnum>("Warning", "You may have unsaved changes.  Save changes?", buttonGroup);
                 buttonGroup.addCallback(new Callback<ButtonEnumerations.YesNoCancelEnum>() {
 
                     @Override
                     public void exec(ButtonEnumerations.YesNoCancelEnum result) {
                         switch (result) {
                             case YES:
                                 dialog.hide();
                                 preview.storeRules(true, new Callback<Boolean>() {
                                     @Override
                                     public void exec(Boolean result) {
                                         okToChange.exec(result);
                                     }
                                 });
                                 break;
                             case NO:
                                 dialog.hide();
                                 preview.revertRuleChanges();                                
                                 okToChange.exec(true);
                                 break;
                             case CANCEL:
                                 okToChange.exec(false);
                                 dialog.hide();
                                 break;
                         }
                     }
                 });
                 dialog.show();
             }
         });
     }
     
     @Override
 	public void beforeShow(final Callback<Boolean> onReadyCallback){
 		showDefaultView(onReadyCallback);
 	}
     
     public void storeRules(Callback<Boolean> callback){
     	preview.storeRules(true, callback);
     }
 }