/* Open Log Viewer
    *
    * Copyright 2011
    *
    * This file is part of the OpenLogViewer project.
    *
    * OpenLogViewer software is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * OpenLogViewer software 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 General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with any OpenLogViewer software.  If not, see http://www.gnu.org/licenses/
   *
   * I ask that if you make any changes to this file you fork the code on github.com!
   *
   */
  package org.diyefi.openlogviewer.coloring;
  
  import java.awt.Color;
  import java.util.List;
  import java.util.LinkedList;
  import java.util.ListIterator;
  
  /**
   * InitialLineColoring is used to provide the coloring for the GenericDataElements.
   * The colors provided should be the most contrasting colors possible.
   * @author Ben Fenner
   */
  public enum InitialLineColoring {
  
  	INSTANCE;
  	// ALMOST_ONE is used to seed colorList with a red that will stay at the end of
  	// the list. If you create a Color with a hue of 1F then it actually gets
  	// created as a Color with a hue of 0F which is identical to the red at the
  	// beginning of the list, which prevents it working as a good book-end.
  	// 0.999F must be used instead of 0.9999F or more because it will get rounded
  	// by the Color constructor to 1F.
  	private static final float ALMOST_ONE = 0.999F;
  	private static final float THREE = 3F;
  	private static final float ONE_THIRD = 1F / THREE;
  	private static final float TWO_THIRDS = 2F / THREE;
  
  	private final List<Color> colorList;
  	private final Color bookEndRed = Color.getHSBColor(ALMOST_ONE, 1.0F, 1.0F);
  
  	private InitialLineColoring() {
  		colorList = new LinkedList<Color>();
  		colorList.add(0, bookEndRed); // Seed with high value red
  	}
  
  	public Color getBestAvailableColor() {
  		Color newColor;
  		int index = 0;
  
  		final Color seedRed = Color.getHSBColor(0.0F, 1.0F, 1.0F);
  		final Color seedGreen = Color.getHSBColor(ONE_THIRD, 1.0F, 1.0F);
  		final Color seedBlue = Color.getHSBColor(TWO_THIRDS, 1.0F, 1.0F);
  		if (!colorList.contains(seedRed)) { // Seed with low value red
  			newColor = seedRed;
  			index = 0;
  		} else if (!colorList.contains(seedGreen)) { // Seed with green
  			newColor = seedGreen;
  			index = 1;
  		} else if (!colorList.contains(seedBlue)) { // Seed with blue
  			newColor = seedBlue;
  			index = 2;
  		} else {
  
  			float hue = 0.0F;
  			float maxDistance = 0.0F;
  			final ListIterator<Color> i = colorList.listIterator();
  			Color c2;
  
  			while (i.hasNext()) {
  				final Color c1 = i.next();
  
  				if (i.hasNext()) {
  					c2 = i.next();
  					i.previous();
  				} else {
  					c2 = colorList.get(colorList.size() - 1);
  				}
  				final float[] hsbValues1 = Color.RGBtoHSB(c1.getRed(), c1.getGreen(), c1.getBlue(), null);
  				final float[] hsbValues2 = Color.RGBtoHSB(c2.getRed(), c2.getGreen(), c2.getBlue(), null);
  				final float distance = hsbValues2[0] - hsbValues1[0];
  				if (distance > maxDistance) {
  					maxDistance = distance;
  					index = colorList.indexOf(c2);
  					hue = hsbValues1[0] + (distance / 2.0F);
  				}
  			}
  			newColor = Color.getHSBColor(hue, 1.0F, 1.0F);
  		}
 		colorList.add(index, newColor);
 		return newColor;
 	}
 
 	public boolean giveBackColor(final Color c) {
 		return colorList.remove(c);
 	}
 
 	public void giveBackAllColors() {
 		while (!colorList.isEmpty()) {
 			colorList.remove(0);
 		}
 		colorList.add(0, bookEndRed);
 	}
 }