/*******************************************************************************
 * Copyright (c) 2012, 2013 Association for Decentralized Information Management in
 * Industry THTH ry.
 * 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.g3d.vtk.handlers;

import javax.vecmath.Vector3d;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.Command;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.handlers.HandlerUtil;
import org.simantics.g3d.math.MathTools;
import org.simantics.g3d.vtk.common.VtkView;
import org.simantics.utils.threads.AWTThread;
import org.simantics.utils.threads.ThreadUtils;

import vtk.vtkCamera;
import vtk.vtkRenderer;

public class ParallelPerspectiveHandler extends AbstractHandler {

	
	@Override
	public Object execute(ExecutionEvent event) throws ExecutionException {
		Command command = event.getCommand();
		boolean oldValue = HandlerUtil.toggleCommandState(command);
		final boolean activate = !oldValue;

		final IWorkbenchPart ap = HandlerUtil.getActiveEditor(event);
		final VtkView panel = (VtkView)ap.getAdapter(VtkView.class);

		ThreadUtils.asyncExec(AWTThread.getThreadAccess(), new Runnable() {

			@Override
			public void run() {
			    vtkRenderer ren = panel.getRenderer();
			    vtkCamera cam = ren.GetActiveCamera();
				if (activate){

					Vector3d focal = new Vector3d(panel.getRenderer().GetActiveCamera().GetFocalPoint());
					Vector3d pos = new Vector3d(panel.getRenderer().GetActiveCamera().GetPosition());
					double dist = MathTools.distance(pos, focal);
					cam.SetParallelScale(dist/4.0);
					// camera must be moved backwards, or graphics get clipped when parallel view is zoomed out
					// TODO : is there a better way to do this?
					Vector3d dir = new Vector3d(pos);
					dir.sub(focal);
					dir.normalize();
					dir.scale(100);
					dir.add(focal);
					cam.SetPosition(dir.x, dir.y, dir.z);

					cam.SetParallelProjection(1);
					ren.ResetCameraClippingRange();
				} else {
				    
				    double scale = cam.GetParallelScale();
					cam.SetParallelProjection(0);
					
					Vector3d focal = new Vector3d(panel.getRenderer().GetActiveCamera().GetFocalPoint());
                    Vector3d pos = new Vector3d(panel.getRenderer().GetActiveCamera().GetPosition());
                    Vector3d dir = new Vector3d(pos);
                    dir.sub(focal);
                    dir.normalize();
                    dir.scale(scale*4.0);
                    dir.add(focal);
                    cam.SetPosition(dir.x, dir.y, dir.z);
					ren.ResetCameraClippingRange();

				}
				panel.refresh();

			}
		});

		return null;

	}
	
	
	
}