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.unit.SpeedUnit;
  import org.djunits.value.vdouble.scalar.Speed;
  import org.opentrafficsim.core.animation.ColorInterpolator;
  import org.opentrafficsim.core.gtu.GTU;
  
  /**
   * Color GTU depending on their speed.
   * <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 27 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 SpeedGTUColorer implements GTUColorer, Serializable
  {
      /** */
      private static final long serialVersionUID = 20150000L;
  
      /** The legend. */
      private final ArrayList<LegendEntry> legend;
  
      /** The speed that corresponds to the last entry in the legend. */
      private final Speed maximumSpeed;
  
      /**
       * Construct a new SpeedGTUColorer.
       * @param maximumSpeed Speed; the speed at (and above) which the returned color will be green
       */
      public SpeedGTUColorer(final Speed maximumSpeed)
      {
          this.maximumSpeed = maximumSpeed;
          this.legend = new ArrayList<>(4);
          Color[] colorTable = {Color.RED, Color.YELLOW, Color.GREEN};
          Speed zeroSpeed = new Speed(0.0, SpeedUnit.KM_PER_HOUR);
          for (int index = 0; index < colorTable.length; index++)
          {
              double ratio = index * 1.0 / (colorTable.length - 1);
              Speed speed = Speed.interpolate(zeroSpeed, maximumSpeed, ratio);
              String label = speed.toString().replaceFirst("\\.0*|,0*", ".0");
              this.legend.add(new LegendEntry(colorTable[index], label, index == 0 ? "stationary" : "driving " + label));
          }
      }
  
      /** {@inheritDoc} */
      @Override
      public final Color getColor(final GTU gtu)
      {
          Speed speed = gtu.getSpeed();
          double ratio = speed.getSI() / this.maximumSpeed.getSI() * (this.legend.size() - 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 "Speed";
      }
  
  }