How i get the last one click button player1 or player2

1

class MainActivity : AppCompatActivity() {

enum class PLAYINGPLAYER {
    FIRST_PLAYER,
    SECOND_PLAYER
}

var playingplayer: PLAYINGPLAYER? = null

var buttonClicked:ArrayList<Int> = ArrayList()

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    playingplayer = PLAYINGPLAYER.FIRST_PLAYER


}

fun imgButtonClicked(v: View) {
    val btnselected = v as Button
    var optionNumber = 0

    when (btnselected.id) {
        R.id.btn1 -> optionNumber = 1
        R.id.btn2 -> optionNumber = 2
        R.id.btn3 -> optionNumber = 3
        R.id.btn4 -> optionNumber = 4
        R.id.btn5 -> optionNumber = 5
        R.id.btn6 -> optionNumber = 6
    }

    action(optionNumber, btnselected)
}


var button1Click = ArrayList<Button>()
var button2Click = ArrayList<Button>()



fun action(optionNumber: Int, btnselected: Button) {
    if (playingplayer == PLAYINGPLAYER.FIRST_PLAYER) {
        btnselected.setBackgroundColor(Color.GREEN)
        buttonClicked.add(optionNumber)
        btnselected.isEnabled = false
        button1Click.add(btnselected)
        playingplayer = PLAYINGPLAYER.SECOND_PLAYER
    }else if (playingplayer == PLAYINGPLAYER.SECOND_PLAYER) {
        btnselected.setBackgroundColor(Color.RED)
        buttonClicked.add(optionNumber)
        btnselected.isEnabled = false
        button2Click.add(btnselected)
        playingplayer = PLAYINGPLAYER.FIRST_PLAYER
    }
    imagebtnState()
}


fun imagebtnState() {


    val btnLast = buttonClicked.get(buttonClicked.size - 1)



    if (buttonClicked.contains(1) && buttonClicked.contains(2)) {
        if ( btnLast == ??? player1 ) {
            imgbBtnBackground.setImageResource(R.drawable.rca)
        }


    } else if (buttonClicked.contains(1) && buttonClicked.contains(2)) {
        if ( btnLast == ??? player2 ) {

            imgbBtnBackground.setImageResource(R.drawable.wac)
        }
    }

}

}

I have 2 player and several buttons , player1 click button player2 click another button when the players press several specific i want change imageButton background.

In (btnLast = ???) what i have put to get last one click in (buttonClicked.contains(1) && buttonClicked.contains(2)) is player 1 or player 2.