//::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
/** @author  John Miller
 *  @version 2.0
 *  @date    Sun Sep 26 15:00:24 EDT 2021
 *  @see     LICENSE (MIT style license file).
 *
 *  @note    Example Model: Call Center for Process-Interaction Simulation
 */

package scalation
package simulation
package process
package example_1                                     // One-Shot

import scalation.random.{Exponential, Uniform}

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/** The `runCallCenter` function is used to launch the `CallCenterModel` class.
 *  > runMain scalation.simulation.process.example_1.runCallCenter
 */
@main def runCallCenter (): Unit = new CallCenterModel ()


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/** The `CallCenterModel` class defines a simple process-interaction model of a call
 *  center where service is provided by one or more tele-service representatives.
 *  Simulates calls coming into a call center where phones have no call waiting.
 *  Caveat: must add 'from' and 'to' components before transport!!
 *  @param name       the name of the simulation model
 *  @param reps       the number of independent replications to run
 *  @param animating  whether to animate the model
 *  @param aniRatio   the ratio of simulation speed vs. animation speed
 *  @param nStop      the number arrivals before stopping
 *  @param stream     the base random number stream (0 to 999)
 */
class CallCenterModel (name: String = "CallCenter", reps: Int = 1, animating: Boolean = true,
                       aniRatio: Double = 8.0, nStop: Int = 100, stream: Int = 0)
      extends Model (name, reps, animating, aniRatio):

    //--------------------------------------------------
    // Intialize Model Constants

    val lambda  = 6.0                                   // customer arrival rate (per hour)
    val mu      = 7.5                                   // customer service rate (per hour)
    val nPhones = 1                                     // the number of Phones (servers)

    //--------------------------------------------------
    // Create Random Variables (RVs)

    val iArrivalRV = Exponential (HOUR / lambda, stream)    // use different random number streams for independence
    val serviceRV  = Exponential (HOUR / mu, stream + 1)
    val moveRV     = Uniform (0.4 * MINUTE, 0.6 * MINUTE, stream + 2)

    //--------------------------------------------------
    // Create Model Components

    val entry    = Source ("entry", this, () => Call (), 0, nStop, iArrivalRV, (200, 290))
    val phone    = Resource ("phone", null, nPhones, serviceRV, (350, 285))
    val hangUp   = Sink ("hangUp", (500, 290))
    val drop     = Sink ("drop", (360, 440))
    val toPhone  = Transport ("toPhone", entry, phone, moveRV)
    val toHangUp = Transport ("toHangUp", phone, hangUp, moveRV)
    val toDrop   = Transport ("toDrop", phone, drop, moveRV)

    addComponent (entry, phone, hangUp, drop, toPhone, toHangUp, toDrop)

    //--------------------------------------------------
    // Specify Scripts for each Type of Simulation Actor

    case class Call () extends SimActor ("c", this):

        override def act (): Unit =
            toPhone.jump ()                              // access (jump to) phone
            if phone.busy then                           // busy => end/drop the call
                toDrop.jump ()                           // indicate the call is dropped
                drop.leave ()                            // end unsuccessful call
            else
                phone.utilize ()                         // successful call => talk
                phone.release ()                         // release the call
                toHangUp.jump ()                         // indicate normal hang up
                hangUp.leave ()                          // normal end call
            end if
        end act

    end Call

    simulate ()
    waitFinished ()
    Model.shutdown ()

end CallCenterModel