content: /*******************************************************************************
   * Copyright (c) 2000, 2008 IBM Corporation and others.
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * which accompanies this distribution, and is available at
   * http://www.eclipse.org/legal/epl-v10.html
   *
   * Contributors:
   *     IBM Corporation - initial API and implementation
   *******************************************************************************/
  package org.eclipse.wst.jsdt.internal.ui.packageview;
  
  import java.lang.reflect.InvocationTargetException;
  import java.util.List;
  
  import org.eclipse.core.resources.IResource;
  import org.eclipse.jface.util.TransferDropTargetListener;
  import org.eclipse.jface.viewers.ISelection;
  import org.eclipse.jface.viewers.IStructuredSelection;
  import org.eclipse.jface.viewers.StructuredViewer;
  import org.eclipse.swt.dnd.DND;
  import org.eclipse.swt.dnd.DropTargetEvent;
  import org.eclipse.swt.dnd.Transfer;
  import org.eclipse.swt.widgets.Shell;
  import org.eclipse.ui.views.navigator.LocalSelectionTransfer;
  import org.eclipse.wst.jsdt.core.IJavaScriptElement;
  import org.eclipse.wst.jsdt.core.JavaScriptModelException;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.reorg.JavaCopyProcessor;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.reorg.JavaMoveProcessor;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.reorg.ReorgPolicyFactory;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.reorg.ReorgUtils;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.reorg.IReorgPolicy.ICopyPolicy;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.reorg.IReorgPolicy.IMovePolicy;
  import org.eclipse.wst.jsdt.internal.ui.dnd.JdtViewerDropAdapter;
  import org.eclipse.wst.jsdt.internal.ui.refactoring.RefactoringMessages;
  import org.eclipse.wst.jsdt.internal.ui.refactoring.reorg.ReorgCopyStarter;
  import org.eclipse.wst.jsdt.internal.ui.refactoring.reorg.ReorgMoveStarter;
  import org.eclipse.wst.jsdt.internal.ui.util.ExceptionHandler;
  
  public class SelectionTransferDropAdapter extends JdtViewerDropAdapter implements TransferDropTargetListener {
  
  	private List fElements;
  	private JavaMoveProcessor fMoveProcessor;
  	private int fCanMoveElements;
  	private JavaCopyProcessor fCopyProcessor;
  	private int fCanCopyElements;
  	private ISelection fSelection;
  
  	private static final long DROP_TIME_DIFF_TRESHOLD= 150;
  
  	public SelectionTransferDropAdapter(StructuredViewer viewer) {
  		super(viewer, DND.FEEDBACK_SCROLL | DND.FEEDBACK_EXPAND);
  	}
  
  	//---- TransferDropTargetListener interface ---------------------------------------
  	
  	public Transfer getTransfer() {
  		return LocalSelectionTransfer.getInstance();
  	}
  	
  	public boolean isEnabled(DropTargetEvent event) {
  		Object target= event.item != null ? event.item.getData() : null;
  		if (target == null)
  			return false;
  		return target instanceof IJavaScriptElement || target instanceof IResource;
  	}
  
  	//---- Actual DND -----------------------------------------------------------------
  	
  	public void dragEnter(DropTargetEvent event) {
  		clear();
  		super.dragEnter(event);
  	}
  	
  	public void dragLeave(DropTargetEvent event) {
  		clear();
  		super.dragLeave(event);
  	}
  	
  	private void clear() {
  		fElements= null;
  		fSelection= null;
  		fMoveProcessor= null;
  		fCanMoveElements= 0;
  		fCopyProcessor= null;
  		fCanCopyElements= 0;
  	}
  	
  	public void validateDrop(Object target, DropTargetEvent event, int operation) {
  		event.detail= DND.DROP_NONE;
  		
  		if (tooFast(event)) 
  			return;
  		
  		initializeSelection();
  				
  		try {
  			switch(operation) {
  				case DND.DROP_DEFAULT:	event.detail= handleValidateDefault(target, event); break;
  				case DND.DROP_COPY: 	event.detail= handleValidateCopy(target, event); break;
  				case DND.DROP_MOVE: 	event.detail= handleValidateMove(target, event); break;
  			}
  		} catch (JavaScriptModelException e){
  			ExceptionHandler.handle(e, PackagesMessages.SelectionTransferDropAdapter_error_title, PackagesMessages.SelectionTransferDropAdapter_error_message); 
  			event.detail= DND.DROP_NONE;
  		}	
  	}
  
  	protected void initializeSelection(){
  		if (fElements != null)
  			return;
  		ISelection s= LocalSelectionTransfer.getInstance().getSelection();
  		if (!(s instanceof IStructuredSelection))
  			return;
  		fSelection= s;	
  		fElements= ((IStructuredSelection)s).toList();
  	}
  	
  	protected ISelection getSelection(){
  		return fSelection;
  	}
  	
  	private boolean tooFast(DropTargetEvent event) {
  		return Math.abs(LocalSelectionTransfer.getInstance().getSelectionSetTime() - (event.time & 0xFFFFFFFFL)) < DROP_TIME_DIFF_TRESHOLD;
  	}	
  
  	public void drop(Object target, DropTargetEvent event) {
  		try{
  			switch(event.detail) {
  				case DND.DROP_MOVE: handleDropMove(target, event); break;
  				case DND.DROP_COPY: handleDropCopy(target, event); break;
  			}
  		} catch (JavaScriptModelException e){
  			ExceptionHandler.handle(e, PackagesMessages.SelectionTransferDropAdapter_error_title, PackagesMessages.SelectionTransferDropAdapter_error_message); 
  		} catch(InvocationTargetException e) {
  			ExceptionHandler.handle(e, RefactoringMessages.OpenRefactoringWizardAction_refactoring, RefactoringMessages.OpenRefactoringWizardAction_exception); 
  		} catch (InterruptedException e) {
  			//ok
  		} finally {
  			// The drag source listener must not perform any operation
  			// since this drop adapter did the remove of the source even
  			// if we moved something.
  			event.detail= DND.DROP_NONE;
  		}
  	}
  	
  	private int handleValidateDefault(Object target, DropTargetEvent event) throws JavaScriptModelException{
  		if (target == null)
  			return DND.DROP_NONE;
  		
  		if ((event.operations & DND.DROP_MOVE) != 0) {
  			return handleValidateMove(target, event);
  		}
  		if ((event.operations & DND.DROP_COPY) != 0) {
  			return handleValidateCopy(target, event);
  		}
  		return DND.DROP_NONE;
  	}
  	
  	private int handleValidateMove(Object target, DropTargetEvent event) throws JavaScriptModelException{
  		if (target == null)
  			return DND.DROP_NONE;
  		
  		if (fMoveProcessor == null) {
  			IMovePolicy policy= ReorgPolicyFactory.createMovePolicy(ReorgUtils.getResources(fElements), ReorgUtils.getJavaElements(fElements));
  			if (policy.canEnable())
  				fMoveProcessor= new JavaMoveProcessor(policy);
  		}
  
  		if (!canMoveElements())
  			return DND.DROP_NONE;	
  
  		if (target instanceof IResource && fMoveProcessor != null && fMoveProcessor.setDestination((IResource)target).isOK())
  			return DND.DROP_MOVE;
  		else if (target instanceof IJavaScriptElement && fMoveProcessor != null && fMoveProcessor.setDestination((IJavaScriptElement)target).isOK())
  			return DND.DROP_MOVE;
  		else
  			return DND.DROP_NONE;	
  	}
  	
  	private boolean canMoveElements() {
  		if (fCanMoveElements == 0) {
  			fCanMoveElements= 2;
  			if (fMoveProcessor == null)
  				fCanMoveElements= 1;
  		}
  		return fCanMoveElements == 2;
  	}
  
  	private void handleDropMove(final Object target, DropTargetEvent event) throws JavaScriptModelException, InvocationTargetException, InterruptedException{
  		IJavaScriptElement[] javaElements= ReorgUtils.getJavaElements(fElements);
  		IResource[] resources= ReorgUtils.getResources(fElements);
  		ReorgMoveStarter starter= null;
  		if (target instanceof IResource) 
  			starter= ReorgMoveStarter.create(javaElements, resources, (IResource)target);
  		else if (target instanceof IJavaScriptElement)
  			starter= ReorgMoveStarter.create(javaElements, resources, (IJavaScriptElement)target);
  		if (starter != null)
  			starter.run(getShell());
  	}
  
  	private int handleValidateCopy(Object target, DropTargetEvent event) throws JavaScriptModelException{
  
  		if (fCopyProcessor == null) {
  			final ICopyPolicy policy= ReorgPolicyFactory.createCopyPolicy(ReorgUtils.getResources(fElements), ReorgUtils.getJavaElements(fElements));
  			fCopyProcessor= policy.canEnable() ? new JavaCopyProcessor(policy) : null;
  		}
  
  		if (!canCopyElements())
  			return DND.DROP_NONE;	
  
  		if (target instanceof IResource && fCopyProcessor != null && fCopyProcessor.setDestination((IResource)target).isOK())
  			return DND.DROP_COPY;
  		else if (target instanceof IJavaScriptElement && fCopyProcessor != null && fCopyProcessor.setDestination((IJavaScriptElement)target).isOK())
  			return DND.DROP_COPY;
  		else
  			return DND.DROP_NONE;					
  	}
  			
  	private boolean canCopyElements() {
  		if (fCanCopyElements == 0) {
  			fCanCopyElements= 2;
  			if (fCopyProcessor == null)
  				fCanCopyElements= 1;
  		}
  		return fCanCopyElements == 2;
  	}		
  	
  	private void handleDropCopy(final Object target, DropTargetEvent event) throws JavaScriptModelException, InvocationTargetException, InterruptedException{
  		IJavaScriptElement[] javaElements= ReorgUtils.getJavaElements(fElements);
  		IResource[] resources= ReorgUtils.getResources(fElements);
  		ReorgCopyStarter starter= null;
  		if (target instanceof IResource) 
  			starter= ReorgCopyStarter.create(javaElements, resources, (IResource)target);
  		else if (target instanceof IJavaScriptElement)
  			starter= ReorgCopyStarter.create(javaElements, resources, (IJavaScriptElement)target);
  		if (starter != null)
  			starter.run(getShell());
  	}
  
  	private Shell getShell() {
  		return getViewer().getControl().getShell();
  	}
  }
  