Rizalt.kt

/**
 * This interface marks the class for use of `Rizalt` library.
 */
interface Rizalt<P: Parcelable>

/**
 * Creates a unique request key for given Fragment class. Key can be left empty
 * to create a default instance.
 */
fun <T, P: Parcelable> KClass<T>.getRequestKeyNameFor(key: String): String where T: Fragment, T: Rizalt<P> {
    return "${this.simpleName}_${key}_REQUEST_KEY"
}

/**
 * Adds the request key in arguments for given Fragment. When this fragment calls
 * [setFragmentRizalt], it will simply use the given request key.
 */
inline fun <reified T, P: Parcelable> T.addRizaltKey(key: String): T where T: Fragment, T: Rizalt<P> {
    arguments?.putString(RIZALT_REQUEST_KEY, T::class.getRequestKeyNameFor(key))
    return this
}

/**
 * Creates a unique result key for the given Fragment class.
 * `Rizalt` API assumes that each Fragment has single result which is [Parcelable].
 * This result is put in a Bundle with the generated key from this method and easily
 * read by `rizalt listener`s.
 */
inline fun <T, reified P: Parcelable> KClass<T>.getResultKeyNameFor(): String where T: Fragment, T: Rizalt<P> {
    return "${this.simpleName}_${P::class.simpleName}_RESULT_KEY"
}

/**
 * Set the result for this Fragment. Request Key is either read from arguments or
 * assumed to be default, and result key is created by the default [getResultKeyNameFor] method.
 *
 * returns; if setting result operation was successful.
 */
inline fun <reified T, reified P: Parcelable> T.setFragmentRizalt(result: P) where T: Fragment, T: Rizalt<P> {
    val key = arguments?.getString(RIZALT_REQUEST_KEY) ?: T::class.getRequestKeyNameFor("")

    setFragmentResult(key, Bundle().apply {
        putParcelable(T::class.getResultKeyNameFor(), result)
    })
}

/**
 * Register a rizalt listener in a fragment. This listens to child fragment manager.
 *
 * @param clazz: Fragment class that should be listened to for results.
 * @param key: Optional key to differentiate between multiple results from the same Fragment type.
 * @param callback: A listener to call when result is received.
 */
inline fun <HostFragment: Fragment, reified T, reified P: Parcelable> HostFragment.setFragmentRizaltListener(
    clazz: KClass<T>,
    key: String = "",
    crossinline callback: (P) -> Unit
) where T: Fragment, T: Rizalt<P> {
    childFragmentManager.setFragmentResultListener(
        clazz.getRequestKeyNameFor(key),
        this
    ) { _, bundle ->
        bundle
            .getParcelable<P>(clazz.getResultKeyNameFor())
            ?.let {
                callback(it)
            }
    }
}

/**
 * Register a rizalt listener in an Activity. This listens to support fragment manager.
 *
 * @param clazz: Fragment class that should be listened to for results.
 * @param key: Optional key to differentiate between multiple results from the same Fragment type.
 * @param callback: A listener to call when result is received.
 */
inline fun <A: AppCompatActivity, T, reified P: Parcelable> A.setFragmentRizaltListener(
    clazz: KClass<T>,
    key: String = "",
    crossinline callback: (P) -> Unit
) where T: Fragment, T: Rizalt<P> {
    supportFragmentManager.setFragmentResultListener(
        clazz.getRequestKeyNameFor(key),
        this
    ) { _, bundle ->
        bundle
            .getParcelable<P>(clazz.getResultKeyNameFor())
            ?.let {
                callback(it)
            }
    }
}

const val RIZALT_REQUEST_KEY = "RIZALT_REQUEST_KEY"