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.util.ArrayList;
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import org.eclipse.core.resources.IResource;
  import org.eclipse.core.runtime.IAdaptable;
  import org.eclipse.jface.util.TransferDropTargetListener;
  import org.eclipse.jface.viewers.ISelection;
  import org.eclipse.jface.viewers.IStructuredSelection;
  import org.eclipse.jface.viewers.ITreeSelection;
  import org.eclipse.jface.viewers.TreePath;
  import org.eclipse.swt.dnd.DND;
  import org.eclipse.swt.dnd.DropTargetEvent;
  import org.eclipse.swt.dnd.Transfer;
  import org.eclipse.ui.IWorkingSet;
  import org.eclipse.ui.views.navigator.LocalSelectionTransfer;
  import org.eclipse.wst.jsdt.core.IJavaScriptElement;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.reorg.ReorgUtils;
  import org.eclipse.wst.jsdt.internal.ui.dnd.JdtViewerDropAdapter;
  import org.eclipse.wst.jsdt.internal.ui.workingsets.OthersWorkingSetUpdater;
  import org.eclipse.wst.jsdt.internal.ui.workingsets.WorkingSetModel;
  
  public class WorkingSetDropAdapter extends JdtViewerDropAdapter implements TransferDropTargetListener {
  	
  	private PackageExplorerPart fPackageExplorer;
  	
  	private IStructuredSelection fSelection;
  	private Object[] fElementsToAdds;
  	private Set fCurrentElements;
  	private IWorkingSet fWorkingSet;
  
  	public WorkingSetDropAdapter(PackageExplorerPart part) {
  		super(part.getTreeViewer(), DND.FEEDBACK_SCROLL | DND.FEEDBACK_EXPAND);
  		fPackageExplorer= part;
  	}
  
  	//---- 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;
  		ISelection selection= LocalSelectionTransfer.getInstance().getSelection();
  		if (!isValidSelection(selection)) {
  			return false;
  		}
  		if (!isValidTarget(target))
  			return false;
  		
  		initializeState(target, selection);
  		return true;
  	}
  
  	//---- Actual DND -----------------------------------------------------------------
  	
  	public void validateDrop(Object target, DropTargetEvent event, int operation) {
  		event.detail= DND.DROP_NONE;
  		switch(operation) {
  			case DND.DROP_DEFAULT:
  			case DND.DROP_COPY:
  			case DND.DROP_MOVE:
  				event.detail= validateTarget(target, operation); 
  				break;
  			case DND.DROP_LINK:
  				event.detail= DND.DROP_NONE; 
  				break;
  		}
  	}
  	
  	private int validateTarget(Object target, int operation) {
  		showInsertionFeedback(false);
  		setDefaultFeedback(DND.FEEDBACK_SCROLL | DND.FEEDBACK_EXPAND);
  		if (!isValidTarget(target))
  			return DND.DROP_NONE;
  		ISelection s= LocalSelectionTransfer.getInstance().getSelection();
  		if (!isValidSelection(s)) {
  			return DND.DROP_NONE;
  		}
  		
  		initializeState(target, s);
  		
  		if (isWorkingSetSelection()) {
  			setDefaultFeedback(DND.FEEDBACK_SCROLL);
  			if (fLocation == LOCATION_BEFORE || fLocation == LOCATION_AFTER) {
  				showInsertionFeedback(true);
  				return DND.DROP_MOVE;
  			}
  			return DND.DROP_NONE;
  		} else {
  			if (isOthersWorkingSet(fWorkingSet) && operation == DND.DROP_COPY)
  				return DND.DROP_NONE;
  			
  			List realJavaElements= new ArrayList();
  			List realResource= new ArrayList();
  			ReorgUtils.splitIntoJavaElementsAndResources(fElementsToAdds, realJavaElements, realResource);
  			if (fElementsToAdds.length != realJavaElements.size() + realResource.size())
  				return DND.DROP_NONE;
  			for (Iterator iter= realJavaElements.iterator(); iter.hasNext();) {
  				IJavaScriptElement element= (IJavaScriptElement)iter.next();
  				if (ReorgUtils.containsElementOrParent(fCurrentElements, element))
  					return DND.DROP_NONE;
  			}
  			for (Iterator iter= realResource.iterator(); iter.hasNext();) {
  				IResource element= (IResource)iter.next();
  				if (ReorgUtils.containsElementOrParent(fCurrentElements, element))
  					return DND.DROP_NONE;
  			}
  			if (!(fSelection instanceof ITreeSelection)) {
  				return DND.DROP_COPY;
  			}
  			ITreeSelection treeSelection= (ITreeSelection)fSelection;
  			TreePath[] paths= treeSelection.getPaths();
  			for (int i= 0; i < paths.length; i++) {
  				TreePath path= paths[i];
  				if (path.getSegmentCount() != 2)
  					return DND.DROP_COPY;
  				if (!(path.getSegment(0) instanceof IWorkingSet))
  					return DND.DROP_COPY;
  				if (paths.length == 1) {
  					IWorkingSet ws= (IWorkingSet)path.getSegment(0);
  					if (OthersWorkingSetUpdater.ID.equals(ws.getId()))
  						return DND.DROP_MOVE;
  				}
  			}
  		}
  		if (operation == DND.DROP_DEFAULT)
  			return DND.DROP_MOVE;
  		return operation;
  	}
  
  	private boolean isValidTarget(Object target) {
  		return target instanceof IWorkingSet;
  	}
  	
  	private boolean isValidSelection(ISelection selection) {
  		return selection instanceof IStructuredSelection;
  	}
  	
  	private boolean isOthersWorkingSet(IWorkingSet ws) {
  		return OthersWorkingSetUpdater.ID.equals(ws.getId());
  	}
  	
  	private void initializeState(Object target, ISelection s) {
  		fWorkingSet= (IWorkingSet)target;
  		fSelection= (IStructuredSelection)s;
  		fElementsToAdds= fSelection.toArray();
  		fCurrentElements= new HashSet(Arrays.asList(fWorkingSet.getElements()));
  	}
  	
  	private boolean isWorkingSetSelection() {
  		for (int i= 0; i < fElementsToAdds.length; i++) {
  			if (!(fElementsToAdds[i] instanceof IWorkingSet))
  				return false;
  		}
  		return true;
  	}
  
  	public void drop(Object target, final DropTargetEvent event) {
  		if (isWorkingSetSelection()) {
  			performWorkingSetReordering();
  		} else {
  			performElementRearrange(event.detail);
  		}
  		// drag adapter has nothing to do, even on move.
  		event.detail= DND.DROP_NONE;
  	}
  
  	private void performWorkingSetReordering() {
  		WorkingSetModel model= fPackageExplorer.getWorkingSetModel();
  		List activeWorkingSets= new ArrayList(Arrays.asList(model.getActiveWorkingSets()));
  		int index= activeWorkingSets.indexOf(fWorkingSet);
  		if (index != -1) {
  			if (fLocation == LOCATION_AFTER)
  				index++;
  			List result= new ArrayList(activeWorkingSets.size());
  			List selected= new ArrayList(Arrays.asList(fElementsToAdds));
  			for (int i= 0; i < activeWorkingSets.size(); i++) {
  				if (i == index) {
  					result.addAll(selected);
  				}
  				Object element= activeWorkingSets.get(i);
  				if (!selected.contains(element)) {
  					result.add(element);
  				}
  			}
  			if (index == activeWorkingSets.size())
  				result.addAll(selected);
  			model.setActiveWorkingSets((IWorkingSet[])result.toArray(new IWorkingSet[result.size()]));
  		}
  	}
  	
  	private void performElementRearrange(int eventDetail) {
  		// only move if target isn't the other working set. If this is the case
  		// the move will happenn automatically by refreshing the other working set
  		if (!isOthersWorkingSet(fWorkingSet)) {
  			List elements= new ArrayList(Arrays.asList(fWorkingSet.getElements()));
  			elements.addAll(Arrays.asList(fElementsToAdds));
  			fWorkingSet.setElements((IAdaptable[])elements.toArray(new IAdaptable[elements.size()]));
  		}
  		if (eventDetail == DND.DROP_MOVE) {
  			ITreeSelection treeSelection= (ITreeSelection)fSelection;
  			Map workingSets= groupByWorkingSets(treeSelection.getPaths());
  			for (Iterator iter= workingSets.keySet().iterator(); iter.hasNext();) {
  				IWorkingSet ws= (IWorkingSet)iter.next();
  				List toRemove= (List)workingSets.get(ws);
  				List currentElements= new ArrayList(Arrays.asList(ws.getElements()));
  				currentElements.removeAll(toRemove);
  				ws.setElements((IAdaptable[])currentElements.toArray(new IAdaptable[currentElements.size()]));
  			}
  		}
  	}
  
  	private Map/*<List<IWorkingSet>>*/ groupByWorkingSets(TreePath[] paths) {
  		Map result= new HashMap();
  		for (int i= 0; i < paths.length; i++) {
  			TreePath path= paths[i];
  			IWorkingSet ws= (IWorkingSet)path.getSegment(0);
  			List l= (List)result.get(ws);
  			if (l == null) {
  				l= new ArrayList();
  				result.put(ws, l);
  			}
  			l.add(path.getSegment(1));
  		}
  		return result;
  	}
  	
  	//---- test methods for JUnit test since DnD is hard to simulate
  	
  	public int internalTestValidateTarget(Object target, int operation) {
  		return validateTarget(target, operation);
  	}
  	
  	public void internalTestDrop(Object target, int eventDetail) {
  		if (isWorkingSetSelection()) {
  			performWorkingSetReordering();
  		} else {
  			performElementRearrange(eventDetail);
  		}
  	}
  }
  