/*******************************************************************************
 * Copyright (c) 2007- VTT Technical Research Centre of Finland.
 * 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:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.proconf.g3d.dnd;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.dnd.DropTargetEvent;
import org.eclipse.swt.dnd.DropTargetListener;
import org.eclipse.swt.dnd.TextTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.dnd.TransferData;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Control;
import org.simantics.db.Resource;
import org.simantics.proconf.g3d.base.ThreeDimensionalEditorBase;
import org.simantics.proconf.g3d.common.StructuredResourceSelection;
import org.simantics.proconf.ui.dnd.ResourceReferenceTransfer;

public class ShapeDropTarget implements DropTargetListener{
	ThreeDimensionalEditorBase editor;
	List<DropListener> listeners;
	final Control control;
    private DropTarget target; 
    
	public ShapeDropTarget(ThreeDimensionalEditorBase editor) {
		this.editor = editor;
		listeners = new ArrayList<DropListener>();
		this.control = editor.getRenderingComposite();
        
        target = new DropTarget(control, DND.DROP_LINK);
        target.setTransfer(new Transfer[] { ResourceReferenceTransfer.getInstance() });
        target.addDropListener(this);  
	}
	
	public void addDropListener(DropListener listener) {
		listeners.add(listener);
	}
	
	public void removeDropListener(DropListener listener) {
		listeners.remove(listener);
	}
	
	@Override
	public void dragEnter(DropTargetEvent event) {
		event.detail = DND.DROP_LINK;
		dragOver(event);
	}
	
	public void dragOperationChanged(DropTargetEvent event) {
    }
	
	public void dropAccept(DropTargetEvent event) {
    }
	
	public void dragLeave(DropTargetEvent event) {
    }

	
	@Override
	public void dragOver(DropTargetEvent event) {
		// FIXME : a hack to get the actual data (probably works only in Windows)
		TransferData data = event.currentDataType;
		if(!TextTransfer.getInstance().isSupportedType(data))
			return;
		Object o = TextTransfer.getInstance().nativeToJava(data);
		
		Point p = getLocalCoords(event);
		editor.getInputProvider().setMouseMoved(true);
		editor.getInputProvider().setMouseX(p.x);
		editor.getInputProvider().setMouseY(p.y);
		editor.run();
		StructuredResourceSelection sel = editor.getSelectionAdapter().getHighlightSelection();
		
		event.data = o;
		Resource ids[] = parseEventData(event);
		for (DropListener l : listeners) {
			if(l.acceptDrop(sel, ids)) {
				event.detail = DND.DROP_LINK;
				return;
			}
		}
		event.detail = DND.DROP_NONE;		
	}
	
	@Override
	public void drop(DropTargetEvent event) {
		StructuredResourceSelection sel = editor.getSelectionAdapter().getHighlightSelection();
		Resource ids[] = parseEventData(event);
		for (DropListener l : listeners) {
			if(l.acceptDrop(sel, ids)) {
				l.doDrop(sel, ids);
				return;
			}
		}
	}
	
	protected Point getLocalCoords(DropTargetEvent event) {
		return editor.getRenderingComposite().toControl(event.x, event.y);
	}
	
	public void dispose()
    {
        target.removeDropListener(this);
        target = null;
    }
	
	private Resource[] parseEventData(DropTargetEvent event) {
        if (ResourceReferenceTransfer.getInstance().isSupportedType(event.currentDataType) && (event.data instanceof Resource[])) {
            return (Resource[]) event.data;
        }
        return null;
    }
}