package org.kuali.student.common.ui.client.configurable.mvc.sections;
   
   import java.util.ArrayList;
   import java.util.HashMap;
   import java.util.Iterator;
   import java.util.List;
   
   import org.kuali.student.common.ui.client.application.Application;
   import org.kuali.student.common.ui.client.widgets.dialog.ConfirmationDialog;
  import org.kuali.student.common.ui.client.widgets.field.layout.layouts.VerticalFieldLayout;
  import org.kuali.student.common.ui.client.widgets.list.KSSelectItemWidgetAbstract;
  import org.kuali.student.common.ui.client.widgets.list.SelectionChangeEvent;
  import org.kuali.student.common.ui.client.widgets.list.SelectionChangeHandler;
  
  import com.google.gwt.event.dom.client.ClickEvent;
  import com.google.gwt.event.dom.client.ClickHandler;
  
  /**
   * A section that contains sections that can be swapped in based on user selection on a KSSelectItemWidgetAbstract
   * 
   * 
   * @author Kuali Student Team
   *
   */
  public class SwapSection extends BaseSection implements HasSectionDeletion{
  	
  	private HashMap<String, Section> swapSectionMap = new HashMap<String, Section>();
  	private KSSelectItemWidgetAbstract selectableWidget;
  	private List<Section> deleted = new ArrayList<Section>();
  	private ConfirmationDialog dialog; 
  	private boolean showConfirmation = true;
  	private List<String> lastSelection = new ArrayList<String>();
  	private List<String> deletionParentKeys;
  	private SwapEventHandler swapEventHandler;
  	protected List<String> prevSelection = new ArrayList<String>();
  	
  	/**
  	 * Constructor for SwapSection, note that the SelectableWidget passed in is not added to the
  	 * UI but is instead used as reference to show different sections.  The widget must still be added
  	 * to a layout as a field or a widget to show in the UI.  A default confirmation dialog will be used.
  	 * @param selectableWidget
  	 */
  	public SwapSection(KSSelectItemWidgetAbstract selectableWidget){
  		this.init(selectableWidget);
  	}
  	
  	public SwapSection(KSSelectItemWidgetAbstract selectableWidget, ConfirmationDialog dialog){
          this.dialog = dialog;
  		this.init(selectableWidget);
  	}
  	
  	private void init(KSSelectItemWidgetAbstract selectableWidget){
  		this.selectableWidget = selectableWidget;
  		
  		if(dialog == null){
  			dialog = 
  				new ConfirmationDialog(Application.getApplicationContext().getMessage("fieldDeletionTitle"),  
  						Application.getApplicationContext().getMessage("fieldDeletionConfirmMessage"));
  		}
  		dialog.getConfirmButton().addClickHandler(new ClickHandler(){
  
  			@Override
  			public void onClick(ClickEvent event) {
  				handleUserSelection();
  				dialog.hide();
  			}
  		});
  		
          dialog.getCancelButton().addClickHandler(new ClickHandler() {
  
              @Override
              public void onClick(ClickEvent event) {
                  for (int i = 0; i < prevSelection.size(); i++) {
                      SwapSection.this.selectableWidget.selectItem(prevSelection.get(i));
                  }
              }
          });
  		
  		selectableWidget.addSelectionChangeHandler(new SelectionChangeHandler(){
  
  			@Override
  			public void onSelectionChange(SelectionChangeEvent event) {
  				if(event.isUserInitiated() && showConfirmation){
  					if(SwapSection.this.selectableWidget.getSelectedItems().size() < lastSelection.size()){
  						dialog.show();
  					}
  					else if(!SwapSection.this.selectableWidget.getSelectedItems().containsAll(lastSelection)){
  //						List<String> selected  = SwapSection.this.selectableWidget.getSelectedItems();
  //						for(int i = 0; i < selected.size(); i++){
  //							String key = selected.get(i);
  //							Section section = swapSectionMap.get(key);
  //							if(section!=null){
  //								if(section.getLayout().isVisible()){
  //									dialog.show();
  //								}
  //							}
  //						}
  						dialog.show();
  					}
 					else{
 						handleUserSelection();
 					}
 				}
 				else if(event.isUserInitiated()){
 					handleUserSelection();
 				}
 				else{
 					handleSelection();
 				}
 				prevSelection.clear();				
 				prevSelection.addAll(lastSelection);
 				lastSelection.clear();
 				lastSelection.addAll(SwapSection.this.selectableWidget.getSelectedItems());
 			}
 		});
 		layout = new VerticalFieldLayout();
 		this.add(layout);
 	}
 	
 	private void handleUserSelection(){
 		List<String> selected  = SwapSection.this.selectableWidget.getSelectedItems();
 		for(int i = 0; i < selected.size(); i++){
 			String key = selected.get(i);
 			showSwappableSection(key);
 		}
 		
 		Iterator<String> it = swapSectionMap.keySet().iterator();
 		while(it.hasNext()){
 			String key = it.next();
 			if(!selected.contains(key)){
 				removeSwappableSection(key);
 			}
 		}
 		//SectionUpdateEvent e = new SectionUpdateEvent();
 		//e.setSection(this);
 		//LayoutController.findParentLayout(layout).fireApplicationEvent(e);
 	}
 	
 	/**
 	 * This is handled differently than handleUserSelection because it is assumed that the client
 	 * is setting the correct values into the widgets, therefore no need to delete sections
 	 * (also reduces chance of actually deleting data before it is even shown)
 	 */
 	private void handleSelection(){
 		List<String> selected  = SwapSection.this.selectableWidget.getSelectedItems();
 		for(int i = 0; i < selected.size(); i++){
 			String key = selected.get(i);
 			showSwappableSection(key);
 		}
 		
 		Iterator<String> it = swapSectionMap.keySet().iterator();
 		while(it.hasNext()){
 			String key = it.next();
 			if(!selected.contains(key)){
 				removeSwappableSection(key);
 			}
 		}
 	}
 	
 	private void showSwappableSection(String key){
 		Section section = swapSectionMap.get(key);
 		if(section != null){
 			if(deleted.contains(section)){
 				deleted.remove(section);
 			}
 			if(!section.getLayout().isVisible()){
 				section.enableValidation(true);
 				section.getLayout().setVisible(true);
 			}
 		}
 		if (swapEventHandler != null){
 		    swapEventHandler.onShowSwappableSection(key, section);
 		}
 	}
 	
 	private void removeSwappableSection(String key){
 		Section section = swapSectionMap.get(key);
 		if(section != null){
 			if(!deleted.contains(section)){
 				deleted.add(section);
 			}
 			if(section.getLayout().isVisible()){
 				section.enableValidation(false);
 				section.getLayout().setVisible(false);
 			}
 
 		}
 		if (swapEventHandler != null){
             swapEventHandler.onRemoveSwappableSection(key, section);
         }
 	}
 	
 	public void enableConfirmation(boolean enable){
 		showConfirmation = enable;
 	}
 	
 	public String addSection(Section section, String swapKey){
 		swapSectionMap.put(swapKey, section);
 		String key = layout.addLayout(section.getLayout());
 		section.getLayout().setVisible(false);
 		if(selectableWidget.getSelectedItems().contains(swapKey)){
 			handleSelection();
 		}
 		sections.add(section);
 		return key;
 	}
 	
 	public String addSection(String key, Section section, String swapKey){
 		swapSectionMap.put(swapKey, section);
 		section.getLayout().setKey(key);
 		String rkey = layout.addLayout(section.getLayout());
 		section.getLayout().setVisible(false);
 		if(selectableWidget.getSelectedItems().contains(swapKey)){
 			handleSelection();
 		}
 		sections.add(section);
 		return rkey;
 	}
 	
 	
 	@Override
 	public String addSection(Section section) {
 		throw new UnsupportedOperationException("Sections can be added to swappable section only through " +
 				"the addSection(Section section, String swapKey) method");
 		
 	}
 
 	@Override
 	public String addSection(String key, Section section) {
 		throw new UnsupportedOperationException("Sections can be added to swappable section only through " +
 				"the addSection(Section section, String swapKey) method");
 	}
 
 	@Override
 	public List<Section> getDeletedSections() {
 		return deleted;
 	}
 
     @Override
     public List<String> getDeletionParentKeys() {
         return deletionParentKeys;
     }
 
     /**
      * deletionParentKeys is optional and is only needed when you want to delete the
      * entire structure in addition to individual fields with in deleted sections.
      * 
      * @see SectionBinding#setModelValue(Section, org.kuali.student.common.ui.client.mvc.DataModel, String)
      */
     @Override
     public void setDeletionParentKey(List<String> deletionParentKeys) {
         this.deletionParentKeys = deletionParentKeys;
     }
 
     public SwapEventHandler getSwapEventHandler() {
         return swapEventHandler;
     }
 
     public void setSwapEventHandler(SwapEventHandler swapEventHandler) {
         this.swapEventHandler = swapEventHandler;
     }
     
 }