package org.kuali.student.lum.program.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.*;
   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 org.kuali.student.lum.program.client.ProgramConstants;
  import org.kuali.student.lum.program.client.properties.ProgramProperties;
  import org.kuali.student.lum.program.client.widgets.EditableHeader;
  
  import com.google.gwt.event.shared.HandlerManager;
  
  public class ProgramRequirementsViewController extends BasicLayout {
  
      public enum ProgramRequirementsViews {
          PREVIEW,
          MANAGE
      }
  
      public static final String PROGRAM_RULES_MODEL_ID = "programRulesModelId";
      private ProgramRequirementsSummaryView preview;
  
      public ProgramRequirementsViewController(Controller controller, HandlerManager eventBus, String name, Enum<?> viewType, boolean isReadOnly, EditableHeader header) {
          super(ProgramRequirementsViewController.class.getName());
          super.setController(controller);
          super.setName(name);
          super.setViewEnum(viewType);
          super.setDefaultModelId(PROGRAM_RULES_MODEL_ID);
          super.setParentController(controller);
  
          this.setDefaultView(ProgramRequirementsViews.PREVIEW);
  
          //not used
          super.registerModel(PROGRAM_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
          String previewTitle = ProgramProperties.get().program_menu_sections_requirements();
          if (isReadOnly && (header != null)) {
              preview = new ProgramRequirementsSummaryView(this, eventBus, ProgramRequirementsViews.PREVIEW, "", ProgramConstants.PROGRAM_MODEL_ID, isReadOnly, header);                                                            
          } else {
              preview = new ProgramRequirementsSummaryView(this, eventBus, ProgramRequirementsViews.PREVIEW, (isReadOnly ? previewTitle : ""), ProgramConstants.PROGRAM_MODEL_ID, isReadOnly);
          }
          super.addView(preview);
  
          if (!isReadOnly) {
              ProgramRequirementsManageView manageView = new ProgramRequirementsManageView(this, ProgramRequirementsViews.MANAGE, "Add and Combine Rules", PROGRAM_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) {
  
                  //moving from PREVIEW to MANAGE page
                  //no dialog if user is going to the Manage Rule page
                  if (viewChangingTo.name().equals(ProgramRequirementsViews.MANAGE.name()))
                  {
                      okToChange.exec(true);
                      return;
                  }
  
                  //moving from MANAGE to PREVIEW page
                  //no dialog if user clicks on the 'Save' or cancel button on the Manage Rule page
                  if (getCurrentView() instanceof ProgramRequirementsManageView) {
                      okToChange.exec(true);
                      return;
                  }
  
                  //moving from MANAGE to other page
                  //TODO show dialog if user clicks on a menu from Manage Rules page                
  
                  //moving from other page to PREVIEW page
                  if (viewChangingTo.name().equals(ProgramRequirementsViews.PREVIEW.name())) {
                      preview.getRules().setupRules(ProgramRequirementsViewController.this, new Callback<Boolean>() {
                          @Override
                          public void exec(Boolean result) {
                             okToChange.exec(result);
                             return;
                         }
                     });
                     return;
                 }
 
                 //moving from PREVIEW to other page (rules have NOT changed)
                 //user is moving to another program section and no changes were made to the rules so allow it to happen
                 if (!((SectionView) getCurrentView()).isDirty()) {
                     okToChange.exec(true);
                     return;
                 }
 
                 //moving from PREVIEW to other page (rules have changed)
                 //user is moving to another program section and rules have been changed, user needs to either save rules or abandon 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(new Callback<Boolean>() {
                                     @Override
                                     public void exec(Boolean result) {
                                         okToChange.exec(true);                                        
                                     }
                                 });
                                 break;
                             case NO:
                                 dialog.hide();
                                 //preview.revertRuleChanges();     //TODO put back if we will NOT reset rules every time user comes to PREVIEW page above...
                                 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 ProgramRequirementsSummaryView getProgramRequirementsView() {
         return preview;
     }
 }