package org.opentrafficsim.road.gtu.lane.perception.mental.ar;
   
   import org.djunits.value.vdouble.scalar.Duration;
   import org.opentrafficsim.base.parameters.ParameterException;
   import org.opentrafficsim.core.dsol.OtsSimulatorInterface;
   import org.opentrafficsim.road.gtu.lane.perception.LanePerception;
   
   /**
    * Class for exponential demand.
   * <p>
   * Copyright (c) 2024-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
   * </p>
   * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
   */
  public class ArTaskExponential extends AbstractArTask
  {
  
      /** Initial level of task demand. */
      private final double initialTaskDemand;
  
      /** Additional task demand. */
      private final double additionalTaskDemand;
  
      /** Time scale at which task demand changes from the initial to the final value. */
      private final Duration tau;
  
      /** Start time of the distraction. */
      private final double start;
  
      /**
       * Constructor.
       * @param id id
       * @param initialTaskDemand initial level of task demand
       * @param finalTaskDemand final level of task demand
       * @param tau time scale at which task demand changes from the initial to the final value
       * @param simulator simulator
       */
      public ArTaskExponential(final String id, final double initialTaskDemand, final double finalTaskDemand, final Duration tau,
              final OtsSimulatorInterface simulator)
      {
          super(id);
          this.initialTaskDemand = initialTaskDemand;
          this.additionalTaskDemand = finalTaskDemand - initialTaskDemand;
          this.tau = tau;
          this.start = simulator.getSimulatorTime().si;
      }
  
      @Override
      public double calculateTaskDemand(final LanePerception perception) throws ParameterException
      {
          double t = perception.getGtu().getSimulator().getSimulatorTime().si - this.start;
          return this.initialTaskDemand + this.additionalTaskDemand * (1.0 - Math.exp(-t / this.tau.si));
      }
  
  }