slap__one_level.kt

class CreateTask(
    private val clock: Clock,
    private val localStorage: LocalStorage,
    private val observers: List<TaskObserver>
) {

    fun invoke(description: String) {
        val newTask = createNewTask(description)
        localStorage.save(newTask)
        notifyAnyObservers(newTask)
    }

    private fun createNewTask(description: String): Task {
        val normalizedDescription = normalize(description)
        return Task(normalizedDescription, Status.NotStarted, clock.now())
    }

    private fun normalize(description: String): String {
        return if (description.length > MAX_DESCRIPTION_LENGTH)
            description.substring(0, MAX_DESCRIPTION_LENGTH - 1) else
            description
    }

    private fun notifyAnyObservers(newTask: Task) {
        observers
            .filter { taskObserver -> taskObserver.observedStatus == Status.NotStarted }
            .forEach { taskObserver -> taskObserver.notify(newTask) }
    }
}