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

import java.util.ArrayList;

import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.PlatformUI;
import org.simantics.utils.ui.ErrorLogger;


/**
 * TODO : This is a copy-paste from old proconf.utils plug-ing:
 * 		: PreferencePage is not ported,
 * 		: Using Webmon ?
 * 
 * 
 * VisualizationScheduler is singleton class that schedules
 * visualization redraws. 
 * 
 * Scheduler has three behaviour patters: 
 * 
 * ONCE : Redraws all visualizations one by one and then sleeps for
 *        a while so that visualizations won't use all available cpu-time.
 *    
 * ALWAYS : Redraws one visualization and sleeps before updating next
 *          visualization.
 *    
 * OFF : uses asyncExec busy-loop (doesn't block eclipse, but other applications may suffer) 
 * 
 * 
 * @author Marko Luukkainen
 *
 */
public class VisualizationScheduler implements Runnable{
    private static VisualizationScheduler instance;
    private Display display;
    private ArrayList<Runnable> visualizations;
    private boolean isDisposed = false;
    private boolean stateFlag = false;
    private static int sleepTime = 40;
    private int index = 0;
    
    public enum SleepType{ONCE,ALWAYS,OFF};
    
    private static SleepType sleepType = SleepType.ONCE;
    
    private VisualizationScheduler() {
        visualizations = new ArrayList<Runnable>();
        display = PlatformUI.getWorkbench().getDisplay();
        //sleepTime = UtilsPlugin.getDefault().getPreferenceStore().getInt(PreferenceConstants.SLEEP_TIME);
        //sleepType = SleepType.valueOf(UtilsPlugin.getDefault().getPreferenceStore().getString(PreferenceConstants.SLEEP_TYPE));
        run();
    }

    /**
     * Scheduler's run loop<br>
     * <br>
     * Loop contains two stages:<br>
     * In the first stage scheduler runs asyncExec for each visualization
     * and after that it runs itself with asyncExec.<br>
     * In the second stage scheduler runs itself with timerExec which allows OS to run it's own code.
     */
    public void run() {
        if (!isDisposed && !display.isDisposed() && !PlatformUI.getWorkbench().isClosing()) {
            switch(sleepType) {
            case ALWAYS:
            	stateFlag = !stateFlag;
				if (stateFlag) {
					if (visualizations.size() > 0) {
						if (index >= visualizations.size())
							index = 0;
						Runnable scene = visualizations.get(index);
						try {
							display.asyncExec(scene);
						} catch (Exception e) {
							ErrorLogger.defaultLogWarning("Scheduler exception", e);
						}
						index++;
					}
					display.asyncExec(this);
				} else {
					display.timerExec(sleepTime, this);
				}
            	break;
            case ONCE: 
            	stateFlag = !stateFlag;
            	if (stateFlag) {
                	for (Runnable scene : visualizations) {
                    	try {
                        	display.asyncExec(scene);
                    	} catch (Exception e) {
                    		ErrorLogger.defaultLogWarning("Scheduler exception",e);
                    	}
                	}
                	display.asyncExec(this);
            	} else {
              		display.timerExec(sleepTime,this);
            	}
            	break;
            case OFF: 
            	for (Runnable scene : visualizations) {
                	try {
                    	display.asyncExec(scene);
                	} catch (Exception e) {
                		ErrorLogger.defaultLogWarning("Scheduler exception",e);
                	}
            	}
            	display.asyncExec(this);
            	break;
            }
        }      
    }
    
    /**
     * Adds visualization into scheduler
     * @param scene
     */
    public void addVisualization(Runnable scene) {
        visualizations.add(scene);
    }
    
    /**
     * Removes visualization from scheduler
     * @param scene
     */
    public void removeVisualization(Runnable scene) {
        visualizations.remove(scene);
    }
    
    /**
     * disposes scheduler.
     *
     */
    public void dispose() {
        isDisposed = true;
    } 
    
    /**
     * @return scheduler's instance
     */
    public static VisualizationScheduler getInstance() {
        if (instance == null)
            instance = new VisualizationScheduler();
        
        return instance;
    }

    /**
     * @return the sleep time of the scheduler
     */
    public int getSleepTime() {
        return sleepTime;
    }

    /**
     * <p>
     * Sets scheduler's sleep time. Larger sleep time gives more
     * cpu time to other applications, but makes visualizations less
     * responsive.
     * </p>
     *  
     * @param sleepTime
     */
    public static void setSleepTime(int time) {
        sleepTime = time;
    }

//	public boolean isSleepAlways() {
//		return sleepAlways;
//	}

	/**
	 * if this flag is set scheludler gives time to other aplications
	 * between each visualization update. Otherwise all visualizations are updated in row and
	 * then priority is given to other applications.
	 * @param sleepAlways
	 */
//	public static void setSleepAlways(boolean sleep) {
//		sleepAlways = sleep;
//	}  
    
    public static SleepType getSleepType() {
    	return sleepType;
    }
    
    public static void setSleepType(SleepType s) {
    	sleepType = s;
    }
    
}