interface Switchable {
    val isOn: Boolean
    fun turnOn()
    fun turnOff()
    fun toggle() = if (isOn) turnOff() else turnOn()
}

interface Lockable {
    val isLocked: Boolean
    fun lock()
    fun unlock()
    fun securityMessage() = if (isLocked) "secure" else "unlocked"
}

abstract class SmartDevice(
    val name: String,
    val room: String
) {
    init {
        require(name.isNotBlank()) { "Device name cannot be blank" }
        require(room.isNotBlank()) { "Room cannot be blank" }
    }

    abstract fun status(): String
    open fun description(): String = "$name in $room"
}

class SmartLight(
    name: String,
    room: String,
    initialBrightness: Int = 50
) : SmartDevice(name, room), Switchable {
    override var isOn = false
        private set

    var brightness = initialBrightness
        private set

    init {
        require(initialBrightness in 0..100) {
            "Brightness must be from 0 to 100"
        }
    }

    override fun turnOn() { isOn = true }
    override fun turnOff() { isOn = false }

    fun setBrightness(level: Int) {
        require(level in 0..100) { "Brightness must be from 0 to 100" }
        brightness = level
        if (level == 0) turnOff() else turnOn()
    }

    override fun status() = if (isOn) "ON at $brightness%" else "OFF"

    override fun description() =
        "${super.description()} — dimmable light"
}

class SmartFan(
    name: String,
    room: String,
    initialSpeed: Int = 1
) : SmartDevice(name, room), Switchable {
    override var isOn = false
        private set

    var speed = initialSpeed
        private set

    init { require(initialSpeed in 1..3) { "Speed must be from 1 to 3" } }

    override fun turnOn() { isOn = true }
    override fun turnOff() { isOn = false }

    fun setSpeed(newSpeed: Int) {
        require(newSpeed in 1..3) { "Speed must be from 1 to 3" }
        speed = newSpeed
    }

    override fun status() = if (isOn) "ON at speed $speed" else "OFF"
    override fun description() = "${super.description()} — three-speed fan"
}

class SmartDoorLock(
    name: String,
    room: String
) : SmartDevice(name, room), Lockable {
    override var isLocked = true
        private set

    override fun lock() { isLocked = true }
    override fun unlock() { isLocked = false }

    override fun status() = if (isLocked) "LOCKED" else "UNLOCKED"
    override fun description() = "${super.description()} — smart lock"
}

class SmartHome(private val homeName: String) {
    private val devices = mutableListOf<SmartDevice>()

    fun add(device: SmartDevice) {
        devices += device
    }

    fun dashboard() {
        println("== $homeName ==")
        devices.forEach { device ->
            println("${device.description()}: ${device.status()}")
        }
    }

    fun goodNight() {
        devices.filterIsInstance<Switchable>().forEach { it.turnOff() }
        devices.filterIsInstance<Lockable>().forEach { it.lock() }
    }
}

fun main() {
    val lamp = SmartLight("Desk lamp", "Bedroom", 70)
    val fan = SmartFan("Ceiling fan", "Living room", 2)
    val door = SmartDoorLock("Front door", "Entrance")

    val home = SmartHome("Oak House")
    home.add(lamp)
    home.add(fan)
    home.add(door)

    val switchableDevices: List<Switchable> = listOf(lamp, fan)
    switchableDevices.forEach { it.turnOn() }
    lamp.setBrightness(40)
    fan.setSpeed(3)
    door.unlock()

    home.dashboard()

    println("\nGood-night routine...")
    home.goodNight()
    home.dashboard()
}