/*******************************************************************************
 * Copyright (c) 2006 Sybase, Inc. 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:
 *     Sybase, Inc. - initial API and implementation
 *******************************************************************************/
package org.eclipse.jst.pagedesigner.dnd.internal;

import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.gef.EditPartViewer;
import org.eclipse.gef.Request;
import org.eclipse.gef.dnd.AbstractTransferDropTargetListener;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jst.jsf.common.ui.internal.guiutils.Alerts;
import org.eclipse.jst.pagedesigner.PDPlugin;
import org.eclipse.jst.pagedesigner.dnd.LocalDropRequest;
import org.eclipse.jst.pagedesigner.viewer.IHTMLGraphicalViewer;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.DropTargetEvent;
import org.eclipse.ui.views.navigator.LocalSelectionTransfer;

/**
 * @author mengbo
 */
public class LocalSelectionDropTargetListener extends
		AbstractTransferDropTargetListener {
	/**
	 * @param viewer
	 */
	public LocalSelectionDropTargetListener(EditPartViewer viewer) {
		super(viewer, LocalSelectionTransfer.getInstance());
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.gef.dnd.AbstractTransferDropTargetListener#createTargetRequest()
	 */
	protected Request createTargetRequest() {
		LocalDropRequest request = new LocalDropRequest();
		request.setLocation(getDropLocation());
		request.setLocalObject(getCurrentLocalObject());
		return request;
	}

	/**
	 * @return the current local object
	 */
	private Object getCurrentLocalObject() {
		ISelection sel = LocalSelectionTransfer.getInstance().getSelection();
		if (sel instanceof IStructuredSelection) {
			return ((IStructuredSelection) sel).getFirstElement();
		}
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.gef.dnd.AbstractTransferDropTargetListener#updateTargetRequest()
	 */
	protected void updateTargetRequest() {
		LocalDropRequest dropRequest = (LocalDropRequest) getTargetRequest();
		dropRequest.setLocation(getDropLocation());
		dropRequest.setLocalObject(getCurrentLocalObject());
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.gef.dnd.AbstractTransferDropTargetListener#setCurrentEvent(org.eclipse.swt.dnd.DropTargetEvent)
	 */
	public void setCurrentEvent(DropTargetEvent currentEvent) {
		super.setCurrentEvent(currentEvent);
		if (currentEvent != null) {
			if (currentEvent.detail != DND.DROP_NONE) {
				currentEvent.detail = DND.DROP_COPY;
			}
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.dnd.DropTargetListener#dragOperationChanged(org.eclipse.swt.dnd.DropTargetEvent)
	 */
	public void dragOperationChanged(DropTargetEvent event) {
		// switch the insert or update
		if ((event.detail & (DND.DROP_COPY)) != 0) {
			LocalDropEditPolicy.setCheckUpdate(false);
		} else {
			LocalDropEditPolicy.setCheckUpdate(true);
		}
		super.dragOperationChanged(event);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.dnd.DropTargetListener#drop(org.eclipse.swt.dnd.DropTargetEvent)
	 */
	public void drop(DropTargetEvent event) {
		String path = ((IHTMLGraphicalViewer) getViewer()).getModel()
				.getBaseLocation();
		IWorkspace workspace = ResourcesPlugin.getWorkspace();
		IWorkspaceRoot root = workspace.getRoot();
		IPath filePath = new Path(path);
		if (root.getFile(filePath).exists()) {
			getViewer().getControl().setFocus();
			super.drop(event);
			LocalDropEditPolicy.setCheckUpdate(true);
		} else {
			Alerts alert = PDPlugin.getAlerts();
			alert.info("LocalSelectionDropTargetListener.MessageDialog.Title",
					"LocalSelectionDropTargetListener.MessageDialog.Message");
		}
	}
}