import kotlin.reflect.KClass

interface Singleton
abstract class UIComponent
abstract class View : Singleton, UIComponent()
abstract class Fragment : UIComponent()

val injectionContext = mutableMapOf<KClass<out Singleton>, Singleton>()

fun <T : Singleton> findSingleton(type: KClass<T>): T {
    if (!injectionContext.containsKey(type))
        injectionContext[type] = type.java.newInstance()
    return injectionContext[type] as T
}

fun <T: Fragment> findFragment(type: KClass<T>): T = type.java.newInstance()

inline fun <reified T : UIComponent> findUIComponent(type: KClass<T>): T? {
    if (T::class is View) {
        return findSingleton<T>(type)
    }
    if (T::class is Fragment) {
        return findFragment<T>(type)
    }
    return null
}