/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.views.navigator;

import java.util.*;

import org.eclipse.core.resources.*;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.jface.viewers.*;
import org.eclipse.swt.dnd.*;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.actions.ReadOnlyStateChecker;
import org.eclipse.ui.part.ResourceTransfer;

/**
 * Implements drag behaviour when items are dragged out of the
 * resource navigator.
 * 
 * @since 2.0
 */
public class NavigatorDragAdapter extends DragSourceAdapter {
	private static final String CHECK_MOVE_TITLE = ResourceNavigatorMessages.getString("DragAdapter.title"); //$NON-NLS-1$
	private static final String CHECK_DELETE_MESSAGE = ResourceNavigatorMessages.getString("DragAdapter.checkDeleteMessage"); //$NON-NLS-1$

	ISelectionProvider selectionProvider;

	private TransferData lastDataType; 	

	/**
	 * Constructs a new drag adapter.
	 */
	public NavigatorDragAdapter(ISelectionProvider provider) {
		selectionProvider = provider;
	}
	/*
	 * @see DragSourceListener#dragFinished(org.eclipse.swt.dnd.DragSourceEvent)
	 */
	public void dragFinished(DragSourceEvent event) {
		LocalSelectionTransfer.getInstance().setSelection(null);

		if (event.doit == false)
			return;

		final int typeMask = IResource.FOLDER | IResource.FILE;
		if (event.detail == DND.DROP_MOVE) {
			//never delete resources when dragging outside Eclipse. 
			//workaround for bug 30543.
			if (lastDataType != null && FileTransfer.getInstance().isSupportedType(lastDataType))
				return;
			
			IResource[] resources = getSelectedResources(typeMask);	
			DragSource dragSource = (DragSource) event.widget;
			Control control = dragSource.getControl();
			Shell shell = control.getShell();
			ReadOnlyStateChecker checker;
			
			if (resources == null || resources.length == 0)
				return;
			
			checker = new ReadOnlyStateChecker(shell, CHECK_MOVE_TITLE, CHECK_DELETE_MESSAGE);
			resources = checker.checkReadOnlyResources(resources);		
			//delete the old elements
			for (int i = 0; i < resources.length; i++) {
				try {
					resources[i].delete(IResource.KEEP_HISTORY | IResource.FORCE, null);
				} catch (CoreException e) {
					e.printStackTrace();
				}
			}
		} else if (event.detail == DND.DROP_TARGET_MOVE) {
			IResource[] resources = getSelectedResources(typeMask);

			// file moved for us by OS, no need to delete the resources, just
			// update the view
			if (resources == null)
				return;
			for (int i = 0; i < resources.length; i++) {
				try {
					resources[i].refreshLocal(IResource.DEPTH_INFINITE, null);
				} catch (CoreException e) {
					e.printStackTrace();
				}
			}
		}
	}
	/*
	 * @see DragSourceListener#dragSetData(org.eclipse.swt.dnd.DragSourceEvent)
	 */
	public void dragSetData(DragSourceEvent event) {
		final int typeMask = IResource.FILE | IResource.FOLDER;
		IResource[] resources = getSelectedResources(typeMask);
		
		if (resources == null || resources.length == 0)
			return;

		lastDataType = event.dataType;
		//use local selection transfer if possible
		if (LocalSelectionTransfer.getInstance().isSupportedType(event.dataType)) {
			event.data = LocalSelectionTransfer.getInstance().getSelection();
			return;
		}
		//use resource transfer if possible
		if (ResourceTransfer.getInstance().isSupportedType(event.dataType)) {
			event.data = resources;
			return;
		}
		//resort to a file transfer
		if (!FileTransfer.getInstance().isSupportedType(event.dataType))
			return;

		// Get the path of each file and set as the drag data
		final int length = resources.length;
		int actualLength = 0; 
		String[] fileNames = new String[length];
		for (int i = 0; i < length; i++) {
			IPath location = resources[i].getLocation();
			// location may be null. See bug 29491.
			if (location != null) 
				fileNames[actualLength++] = location.toOSString();
		}
		if (actualLength == 0)
			return;
		// was one or more of the locations null?
		if (actualLength < length) {
			String[] tempFileNames = fileNames;
			fileNames = new String[actualLength];
			for (int i = 0; i < actualLength; i++)
				fileNames[i] = tempFileNames[i];
		}
		event.data = fileNames;
	}

	/*
	 * @see DragSourceListener#dragStart(org.eclipse.swt.dnd.DragSourceEvent)
	 */
	public void dragStart(DragSourceEvent event) {
		lastDataType = null;
		// Workaround for 1GEUS9V
		DragSource dragSource = (DragSource) event.widget;
		Control control = dragSource.getControl();
		if (control != control.getDisplay().getFocusControl()) {
			event.doit = false;
			return;
		}

		IStructuredSelection selection =
			(IStructuredSelection) selectionProvider.getSelection();
		for (Iterator i = selection.iterator(); i.hasNext();) {
			Object next = i.next();
			if (!(next instanceof IFile || next instanceof IFolder)) {
				event.doit = false;
				return;
			}
		}
		if (selection.isEmpty()) {
			event.doit = false;
			return;
		}
		LocalSelectionTransfer.getInstance().setSelection(selection);
		event.doit = true;
	}
	
	private IResource[] getSelectedResources(int resourceTypes) {
		List resources = new ArrayList();
		IResource[] result = new IResource[0];

		ISelection selection = selectionProvider.getSelection();
		if (!(selection instanceof IStructuredSelection) || selection.isEmpty()) {
			return null;
		}
		IStructuredSelection structuredSelection = (IStructuredSelection) selection;
		if (structuredSelection == null)
			return null;

		// loop through list and look for matching items
		Iterator enum = structuredSelection.iterator();
		while (enum.hasNext()) {
			Object obj = enum.next();
			if (obj instanceof IResource) {
				IResource res = (IResource) obj;
				if ((res.getType() & resourceTypes) == res.getType()) {
					resources.add(res);
				}
			}
		}
		result = new IResource[resources.size()];
		resources.toArray(result);
		return result;
	}
}