/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2014 by RapidMiner and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapidminer.com
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package com.rapidminer.gui.flow;

import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.swing.Timer;

import com.rapidminer.operator.Operator;

/** Timer used to roll out names of operators.
 * 
 *  @author Simon Fischer*/
public class InterpolationMap {

	private static final long DELAY = 300;
	private static final long INTERVAL = 500;
	private static final int REPAINT_DELAY = 50;

	/** This component will be repainted regularly if there are pending rollouts. */
	private final Component component;
	private final Map<Operator,InterpolatedValue> map = new HashMap<Operator,InterpolatedValue>();
	
	private final Timer timer = new Timer(REPAINT_DELAY,new ActionListener() {
		@Override
		public void actionPerformed(ActionEvent e) {
			fireRepaint();
		}
	});
	
	private static class InterpolatedValue {
		private final long startTime = System.currentTimeMillis();
		/** True if interpolating from 0 to {@link #extensionValue} and false
		 *  if interpolating from {@link #extensionValue} to 0. */
		private final boolean up;
		private double extensionValue = 1d;
		private InterpolatedValue(boolean up, double extensionValue) {
			this.up = up;
			this.extensionValue = extensionValue;
		}
		/** Returns the interpolated value at this point of time. */
		private double getValue() {
			long now = System.currentTimeMillis();
			if (up) {
				if (now < startTime + DELAY) {
					return 0d;
				} else if (now > startTime + DELAY + INTERVAL){
					return extensionValue;
				} else {
					return extensionValue*damp(((double)now - (double)startTime - DELAY) / INTERVAL); 
				}
			} else {
				if (now < startTime) {
					return extensionValue;
				} else if (now > startTime + INTERVAL) {
					return 0d;
				} else {
					return extensionValue - extensionValue*damp(((double)now - (double)startTime) / INTERVAL);
				}
			}
		}
		
		/** Returns true iff time is up. */
		private boolean isDone(long now) {
			return //(up && (now > startTime + DELAY + INTERVAL)) ||
				(!up && (now > startTime + INTERVAL));
		}
		
		/** Rescales the interpolated value to make it smoother. */
		private double damp(double value) {
			return Math.sqrt(value);
		}
	}
	
	public InterpolationMap(Component component) {
		this.component = component;
		timer.setRepeats(false);		
	}
	
	protected void fireRepaint() {
		component.repaint();
		cleanUp();
		if (!map.isEmpty() && !timer.isRunning()) {
			timer.start();
		}		
	}

	/** Starts interpolating the extension value for the given operator. */
	public void rollOut(Operator operator) {
		map.put(operator, new InterpolatedValue(true, 1d));
		if (!timer.isRunning()) {
			timer.start();
		}
	}
	
	/** Starts interpolating the extension value for the given operator in the opposite direction,
	 *  starting with the current value. */
	public void rollIn(Operator operator) {
		map.put(operator, new InterpolatedValue(false, getValue(operator)));		
		if (!timer.isRunning()) {
			timer.start();
		}
	}
	
	/** Returns the current interpolated value for the given operator. */
	public double getValue(Operator op) {
		InterpolatedValue val = map.get(op);
		if (val == null) {
			return 0d;
		} else {
			double value = val.getValue();
			return value;
		}
	}
 
	/** Removes unused ({@link InterpolatedValue#isDone(long)}) values. */
	private void cleanUp() {
		long now = System.currentTimeMillis();
		Iterator<Map.Entry<Operator, InterpolatedValue>> i = map.entrySet().iterator();
		while (i.hasNext()) {
			Map.Entry<Operator, InterpolatedValue> entry = i.next();
			if (entry.getValue().isDone(now)) {
				i.remove();
			}
		}
	}
	
	public void clear() {
		map.clear();
	}
}