class Configurator {
    fun addOperation(triggerOnEvent: Lifecycle.Event, operation: (LifecycleOwner) -> Unit)
    fun manageBy(lifecycleOwner: LifecycleOwner)
}

fun <T, R: Any?> Configurator.bind(
    target: T,
    bindAction: (LifecycleOwner, T) -> R,
    bindOnEvent: Lifecycle.Event,
    unbindAction: (LifecycleOwner, T, R) -> Unit,
    unbindOnEvent: Lifecycle.Event = bindOnEvent.oppositeEvent()
) {
    var result: R? = null
    addOperation(bindOnEvent) { result = bindAction(it, target) }
    addOperation(unbindOnEvent) { unbindAction(it, target, result!!) }
}

fun <T> Configurator.Builder.bindObservable(
    observable: Observable<T>,
    action: (Observable<T>) -> Disposable,
    bindOnEvent: Lifecycle.Event = Lifecycle.Event.ON_CREATE,
    unbindOnEvent: Lifecycle.Event = bindOnEvent.oppositeEvent()
) {
    bind(
        target = observable to action,
        bindAction = { _, (stream, act) ->
            act(stream)
        },
        bindOnEvent = bindOnEvent,
        unbindAction = { _, _, subscription ->
            subscription.dispose()
        },
        unbindOnEvent
    )
}

class Configurator {
    fun manageBy(lifecycleOwner: LifecycleOwner)
    class Builder {
        fun addOperation(triggerOnEvent: Lifecycle.Event, operation: Operation)
        fun build(): Configurator
    }
}

fun LifecycleOwner.configure(block: Configurator.Builder.() -> Unit) {
    Configurator.Builder()
        .apply(block)
        .build()
        .manageBy(this)
}

class TimeWastingFragment : Fragment() {
    private val timeSpent = MutableLiveData<Long>()
    private val color = MutableLiveData<Int>()
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val binding = FragmentTimeWastingBinding.inflate(inflater, container, false)
        viewLifecycleOwner.configure {
            bindState(timeSpent, binding.txtTime) { txtView, time ->
                txtView.text = "$time"
            }
            bindState(color, binding.root) { view, color ->
                view.setBackgroundColor(color)
            }
            bindObservable(
                observable = Observable.interval(1, TimeUnit.SECONDS),
                action = { source ->
                  source
                    .observeOn(AndroidSchedulers.mainThread())
                    .subscribe(
                      {
                        timeSpent.value = timeSpent.value!! + 1
                      },
                      Throwable::printStackTrace
                    )
                },
                bindOnEvent = Lifecycle.Event.ON_START
            )
            val colorChangeStream = PublishSubject.create<Unit>()
            bindClicks(
                view = binding.root,
                clickListener = {
                  color.value = generateRandomColor()
                  colorChangeStream.onNext(Unit)
                }
            )
            bindObservable(
                observable = colorChangeStream
                  .startWith(Unit)
                  .switchMap { Observable.interval(5,5, TimeUnit.SECONDS) },
                action = { source ->
                  source
                    .observeOn(AndroidSchedulers.mainThread())
                    .subscribe(
                      {
                        color.value = generateRandomColor()
                      },
                      Throwable::printStackTrace
                    )
                },
                bindOnEvent = Lifecycle.Event.ON_RESUME
            )
        }
        return binding.root
    }
}