/* 
 * Copyright (c) 2008 Stiftung Deutsches Elektronen-Synchrotron, 
 * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY.
 *
 * THIS SOFTWARE IS PROVIDED UNDER THIS LICENSE ON AN "../AS IS" BASIS. 
 * WITHOUT WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED 
 * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE AND 
 * NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE 
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. SHOULD THE SOFTWARE PROVE DEFECTIVE 
 * IN ANY RESPECT, THE USER ASSUMES THE COST OF ANY NECESSARY SERVICING, REPAIR OR 
 * CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. 
 * NO USE OF ANY SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
 * DESY HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, 
 * OR MODIFICATIONS.
 * THE FULL LICENSE SPECIFYING FOR THE SOFTWARE THE REDISTRIBUTION, MODIFICATION, 
 * USAGE AND OTHER RIGHTS AND OBLIGATIONS IS INCLUDED WITH THE DISTRIBUTION OF THIS 
 * PROJECT IN THE FILE LICENSE.HTML. IF THE LICENSE IS NOT INCLUDED YOU MAY FIND A COPY 
 * AT HTTP://WWW.DESY.DE/LEGAL/LICENSE.HTM
 */
 /**
 * 
 */
package org.csstudio.dal.ui.internal.dnd;

import org.csstudio.dal.ui.dnd.rfc.IProcessVariableAdressReceiver;
import org.csstudio.dal.ui.dnd.rfc.IShowControlSystemDialogStrategy;
import org.csstudio.dal.ui.dnd.rfc.ProcessVariableAddressTransfer;
import org.csstudio.dal.ui.dnd.rfc.ProcessVariableExchangeUtil;
import org.csstudio.platform.model.pvs.IProcessVariableAddress;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.DropTargetAdapter;
import org.eclipse.swt.dnd.DropTargetEvent;
import org.eclipse.swt.dnd.TextTransfer;

public class ProcessVariableAdressDropTargetAdapter extends DropTargetAdapter {
	private IProcessVariableAdressReceiver _receiver;

	private IShowControlSystemDialogStrategy _showControlSystemDialogStrategy;

	public ProcessVariableAdressDropTargetAdapter(
			IProcessVariableAdressReceiver pvCallback,
			IShowControlSystemDialogStrategy showControlSystemDialogStrategy) {
		assert pvCallback != null;
		assert showControlSystemDialogStrategy != null;
		_receiver = pvCallback;
		_showControlSystemDialogStrategy = showControlSystemDialogStrategy;
	}

	@Override
	public void drop(final DropTargetEvent event) {
		IProcessVariableAddress[] pvs = new IProcessVariableAddress[0];

		if (ProcessVariableAddressTransfer.getInstance().isSupportedType(event.currentDataType)) {
			pvs = (IProcessVariableAddress[]) ProcessVariableAddressTransfer.getInstance()
					.nativeToJava(event.currentDataType);
		} else if (TextTransfer.getInstance().isSupportedType(
				event.currentDataType)) {
			String rawName = (String) TextTransfer.getInstance().nativeToJava(
					event.currentDataType);

			// TODO: Strategy einbauen, an welcher sich entscheidet, ob nach dem
			// Control-Systeme gefragt wird (z.B. sollte beim Drop von Strings
			// mit Aliasen nicht
			// auf Krampf versucht werden, eine PV aufzul�sen)
			IProcessVariableAddress pv = ProcessVariableExchangeUtil
					.parseProcessVariableAdress(rawName,
							_showControlSystemDialogStrategy
									.showControlSystem(rawName));

			pvs = new IProcessVariableAddress[] { pv };
		}

		if (pvs.length > 0) {
			_receiver.receive(pvs, event);
		}
	}

	@Override
	public void dropAccept(final DropTargetEvent event) {
		if (!isSupportedType(event)) {
			event.detail = DND.DROP_NONE;
		} else {
			event.detail = DND.DROP_COPY;
		}
	}

	@Override
	public void dragEnter(final DropTargetEvent event) {
		if (!isSupportedType(event)) {
			event.detail = DND.DROP_NONE;
		} else {
			event.detail = DND.DROP_COPY;
		}
	}

	@Override
	public void dragOver(final DropTargetEvent event) {
		if (!isSupportedType(event)) {
			event.detail = DND.DROP_NONE;
		} else {
			event.detail = DND.DROP_COPY;
		}
	}

	private boolean isSupportedType(DropTargetEvent event) {
		boolean supported = (ProcessVariableAddressTransfer.getInstance().isSupportedType(
				event.currentDataType) || TextTransfer.getInstance()
				.isSupportedType(event.currentDataType));

		return supported;
	}
}