ResourceSOLID.kt

sealed class Resource<out T> {
    
    data class Success<out T>(val data: T) : Resource<T>()
    data class Loading<out T>(val partialData: T? = null) : Resource<T>()
    data class Failure<out T>(val throwable: Throwable? = null) : Resource<T>()

}
 
val Resource<T>.extractData: T? get() = when (this) {
    is Success -> data
    is Loading -> partialData
    is Failure -> null
}
    
inline fun <Y> Resource<T>.mapResource(crossinline transform: (T) -> Y): Resource<Y> = try {
    when (this) {
        is Success<T> -> Success<Y>(transform(data))
        is Loading<T> -> Loading<Y>(partialData?.let { transform(it) })
        is Failure<T> -> Failure<Y>(throwable)
    }
} catch (e: Throwable) {
    Resource.Failure<Y>(e)
}

fun Resource<T>.onSuccess(onSuccess: (data: T) -> Unit): Resource<T> {
    if (this is Success)
        onSuccess(data)

    return this
}

fun Resource<T>.onLoading(onLoading: (partialData: T?) -> Unit): Resource<T> {
    if (this is Loading)
        onLoading(partialData)

    return this
}

fun Resource<T>.onFailure(onFailure: (throwable: Throwable?) -> Unit): Resource<T> {
    if (this is Failure)
        onFailure(throwable)

    return this
}