var
    stayLosses = 0
    stayWins = 0
    switchLosses = 0
    switchWins = 0
    tmp
        stage = 1    //The game has two basic stages, and stage 3 occurs when the game is over.
        doors[3] //A list of all doors in the world---necessary to ensure that the door with the car does not open.
        obj/Door
            carDoor
            openDoor    //The first door that the host opens.
            firstChoice //The first door that the user picks.

mob
    Login() //Assign door numbers and call new_game.
        var
            n = 1    //Assigns each door its door number.
            obj/Door
                doorOne = new(3, 3, 1)
                doorTwo = new(3, 5, 1)
                doorThree = new(3, 7, 1)
        for(var/obj/Door/D in world)
            D.doorNumber = n
            n++
        new_game()
        return ..()

    verb
        new_game()  //Set game variables to initial values.
            firstChoice = null
            carDoor = null
            openDoor = null
            var/obj/Door/D
            for(D in doors)
                doors.Remove(D)
            for(D in world)
                doors.Add(D)
            stage = 1

obj/Door
    var/doorNumber
    icon = 'door.dmi'
    
    New()
        icon_state = "closed"
        return ..()

    verb
        select()    //Pick a door.
            if(src == openDoor && stage < 3) //If it's the third stage, the game will restart anyway.
                usr << "That door is already open."
            else
                switch(stage)
                    if(1)    //Open a random door
                        src.icon_state = "selected"
                        firstChoice = src
                        carDoor = doors[rand(1, 2)]
                        doors.Remove(carDoor)   //To ensure that the car door is not opened.
                        if(src != carDoor)  //Otherwise, a runtime error could occur.
                            doors.Remove(src)   //To ensure that the door the user picked is not open.
                        openDoor = doors[rand(1, doors.len)]
                        openDoor.icon_state = "goat"
                        usr << "You pick Door [src.doorNumber]. Monty Hall opens Door [openDoor.doorNumber] to reveal a goat. Do you switch or stay?"
                        stage = 2
                    if(2)    //Open the door the user picks and see if he wins. Increment the appropriate variable.
                        carDoor.icon_state = "car"
                        usr << "You open Door [src.doorNumber] and find . . . "
                        if(src == carDoor)
                            usr << "a car! You'll be cruising in style from now on."
                            for(var/obj/Door/D in world)    //This is necessary to open the remaining door.
                                if(D.icon_state == "closed")
                                    D.icon_state = "goat"
                            if(src == firstChoice)
                                stayWins++
                            else
                                switchWins++
                        else
                            usr << "a goat! (And you don't actually get to keep it, either.)"
                            src.icon_state = "goat"
                            if(src == firstChoice)
                                stayLosses++
                            else
                                switchLosses++
                        stage = 3
                    else    //Restart.
                        usr << "Game is completed, so restarting now . . ."
                        return usr.new_game()

    Click()
        if(stage < 3)
            select()
        else
            return usr.new_game()