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

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

import scalation.random.Uniform

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


//::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
/** The `EmerDeptModel` class defines a simple process-interaction model of an
 *  Emergency Department (ED) model where service is provided by one or more nurses
 *  and one or more doctors.   A patient will first see a nurse and then a doctor.
 *  @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 EmerDeptModel (name: String = "EmerDept", reps: Int = 1, animating: Boolean = true,
                     aniRatio: Double = 2.0, nStop: Int = 100, stream: Int = 0)
      extends Model (name, reps, animating, aniRatio):

    //--------------------------------------------------
    // Initialize Model Constants

    val ia_time    = (2000.0, 4000.0)                   // patient inter-arrival time range
    val nurse_ser  = (7000.0, 9000.0)                   // nurse service time range
    val doctor_ser = (5000.0, 7000.0)                   // doctor service time range
    val mv_time    = (900.0, 1100.0)                    // move time range
    val nurses     = 3                                  // number of nurses
    val doctors    = 2                                  // number of doctors

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

    val iArrivalRV = Uniform (ia_time, stream)          // use different random number streams for independence
    val nurseRV    = Uniform (nurse_ser, stream + 1)
    val doctorRV   = Uniform (doctor_ser, stream + 2)
    val moveRV     = Uniform (mv_time, stream + 3)

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

    val entry     = Source ("entry", this, () => Patient (), 0, nStop, iArrivalRV, (70, 340))
    val nurseQ    = WaitQueue ("nurseQ", (230, 340))
    val nurse     = Resource ("nurse", nurseQ, nurses, nurseRV, (250, 335))
    val doctorQ   = WaitQueue ("doctorQ", (440, 340))
    val doctor    = Resource ("doctor", doctorQ, doctors, doctorRV, (460, 335))
    val door      = Sink ("door", (640, 340))
    val toNurseQ  = Transport ("toNurseQ", entry, nurseQ, moveRV)
    val toDoctorQ = Transport ("toDoctorQ", nurse, doctorQ, moveRV)
    val toDoor    = Transport ("toDoor", doctor, door, moveRV)

    addComponent (entry, nurseQ, nurse, doctorQ, doctor, door, toNurseQ, toDoctorQ, toDoor)

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

    case class Patient () extends SimActor ("p", this):

        override def act (): Unit =
            toNurseQ.move ()                            // move to queue to see a nurse
            if nurse.busy then nurseQ.waitIn ()         // wait if all nurses are busy
            else nurseQ.noWait ()                       // record no waiting
            nurse.utilize ()                            // nurse's examination
            nurse.release ()                            // relaase nurse

            toDoctorQ.move ()                           // move to queue to see a doctor
            if doctor.busy then doctorQ.waitIn ()       // wait if all doctors are busy
            else nurseQ.noWait ()                       // record no waiting
            doctor.utilize ()                           // doctor's examination
            doctor.release ()                           // relaase doctor
            toDoor.move ()                              // move to door
            door.leave ()                               // exit the ED
        end act

    end Patient

    simulate ()
    waitFinished ()
    Model.shutdown ()

end EmerDeptModel