package org.opentrafficsim.core.animation.gtu.colorer;
   
   import java.awt.Color;
   import java.io.Serializable;
   import java.util.ArrayList;
   import java.util.Collections;
   import java.util.List;
   
   import org.djunits.value.vdouble.scalar.Acceleration;
  import org.opentrafficsim.core.animation.ColorInterpolator;
  import org.opentrafficsim.core.gtu.GTU;
  
  /**
   * Color GTUs based on their current acceleration.
   * <p>
   * Copyright (c) 2013-2019 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="http://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
   * <p>
   * @version $Revision: 4763 $, $LastChangedDate: 2018-11-19 11:04:56 +0100 (Mon, 19 Nov 2018) $, by $Author: averbraeck $,
   *          initial version 29 mei 2015 <br>
   * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
   */
  public class AccelerationGTUColorer implements GTUColorer, Serializable
  {
      /** */
      private static final long serialVersionUID = 201500001L;
  
      /** The legend. */
      private final ArrayList<LegendEntry> legend;
  
      /** The deceleration that corresponds to the first entry in the legend. */
      private final Acceleration maximumDeceleration;
  
      /** The deceleration that corresponds to the last entry in the legend. */
      private final Acceleration maximumAcceleration;
  
      /** Negative scale part of the range of colors (excluding the zero value). */
      private static Color[] decelerationColors = { Color.MAGENTA, Color.RED, Color.ORANGE, Color.YELLOW };
  
      /** Positive scale part of the range of colors (including the zero value). */
      private static Color[] accelerationColors = { Color.YELLOW, Color.GREEN, Color.BLUE };
  
      /**
       * Construct a new AccelerationGTUColorer.
       * @param maximumDeceleration Acceleration; the deceleration (negative acceleration) that corresponds to the first (red)
       *            legend entry
       * @param maximumAcceleration Acceleration; the deceleration that corresponds to the last (blue) legend entry
       */
      public AccelerationGTUColorer(final Acceleration maximumDeceleration, final Acceleration maximumAcceleration)
      {
          this.maximumDeceleration = maximumDeceleration;
          this.maximumAcceleration = maximumAcceleration;
          this.legend = new ArrayList<>(6);
          for (int index = 0; index < decelerationColors.length - 1; index++)
          {
              double ratio = index * 1.0 / (decelerationColors.length - 1);
              Acceleration acceleration = Acceleration.interpolate(this.maximumDeceleration, Acceleration.ZERO, ratio);
              String label = acceleration.toString().replaceFirst("\\.0*", ".0");
              this.legend.add(new LegendEntry(decelerationColors[index], label, "deceleration" + label));
          }
          for (int index = 0; index < accelerationColors.length; index++)
          {
              double ratio = index * 1.0 / (accelerationColors.length - 1);
              Acceleration acceleration = Acceleration.interpolate(Acceleration.ZERO, this.maximumAcceleration, ratio);
              String label = acceleration.toString().replaceFirst("\\.0*", ".0");
              this.legend.add(new LegendEntry(accelerationColors[index], label, "acceleration" + label));
          }
      }
  
      /** {@inheritDoc} */
      @Override
      public final Color getColor(final GTU gtu)
      {
          Acceleration acceleration = gtu.getAcceleration();
          double ratio;
          if (acceleration.getSI() < 0)
          {
              ratio = decelerationColors.length - 1
                      - acceleration.getSI() / this.maximumDeceleration.getSI() * (decelerationColors.length - 1);
          }
          else
          {
              ratio = acceleration.getSI() / this.maximumAcceleration.getSI() * (accelerationColors.length - 1)
                      + decelerationColors.length - 1;
          }
          if (ratio <= 0)
          {
              return this.legend.get(0).getColor();
          }
          if (ratio >= this.legend.size() - 1)
          {
              return this.legend.get(this.legend.size() - 1).getColor();
          }
          // Interpolate
          int floor = (int) Math.floor(ratio);
          return ColorInterpolator.interpolateColor(this.legend.get(floor).getColor(), this.legend.get(floor + 1).getColor(),
                  ratio - floor);
      }
 
     /** {@inheritDoc} */
     @Override
     public final List<LegendEntry> getLegend()
     {
         return Collections.unmodifiableList(this.legend);
     }
 
     /** {@inheritDoc} */
     @Override
     public final String toString()
     {
         return "Acceleration";
     }
 
 }