Number of base generic delegates to construct custom delegates

delegates.kt

typealias ExtensionItemDelegate<T> = ItemDelegate<T, ExtensionViewHolder<T>>

class LayoutItemDelegate<I>(
        private val type: Class<out I>,
        @LayoutRes private val layoutId: Int
) : ExtensionItemDelegate<I> {

    override fun itemType() = type

    override fun createVewHolder(parent: ViewGroup) = ExtensionViewHolder<I>(parent.inflate(layoutId))

    override fun bindView(position: Int, item: I, holder: ExtensionViewHolder<I>) {
        holder.holdItem = item
    }

    override fun bindView(position: Int, item: I, holder: ExtensionViewHolder<I>, payloads: List<Any>) {
        holder.holdItem = item
    }
}

class CreateItemDelegate<I>(
        private val origin: ExtensionItemDelegate<I>,
        private val createBlock: ExtensionViewHolder<I>.() -> Unit
) : ExtensionItemDelegate<I> by origin {
    override fun createVewHolder(parent: ViewGroup) = origin.createVewHolder(parent).apply(createBlock)
}

class BindItemDelegate<I>(
        private val origin: ExtensionItemDelegate<I>,
        private val bindBlock: ExtensionViewHolder<I>.(I) -> Unit
) : ExtensionItemDelegate<I> by origin {
    override fun bindView(position: Int, item: I, holder: ExtensionViewHolder<I>) {
        origin.bindView(position, item, holder)
        holder.holdItem?.let { holder.bindBlock(it) }
    }
}

class BindPayloadsItemDelegate<I>(
        private val origin: ExtensionItemDelegate<I>,
        private val bindBlock: ExtensionViewHolder<I>.(I, List<Any>) -> Unit
) : ExtensionItemDelegate<I> by origin {

    override fun bindView(position: Int, item: I, holder: ExtensionViewHolder<I>, payloads: List<Any>) {
        origin.bindView(position, item, holder, payloads)
        holder.holdItem?.let { holder.bindBlock(it, payloads) }
    }
}

class ClickableItemDelegate<I>(
        private val origin: ExtensionItemDelegate<I>,
        private val onClick: (I) -> Unit
) : ExtensionItemDelegate<I> by origin {
    override fun createVewHolder(parent: ViewGroup) =
            origin.createVewHolder(parent).apply {
                itemView bindClick onClick
            }
}

class ClickableWithPosItemDelegate<I>(
        private val origin: ExtensionItemDelegate<I>,
        private val clickListener: (I, Int) -> Unit
) : ExtensionItemDelegate<I> by origin {
    override fun createVewHolder(parent: ViewGroup) = origin.createVewHolder(parent).apply {
        itemView.setSafeOnClickListener { holdItem?.let { clickListener(it, adapterPosition) } }
    }
}

inline fun <reified T> itemDelegate(@LayoutRes layoutId: Int) = LayoutItemDelegate(T::class.java, layoutId)

fun <T> ExtensionItemDelegate<T>.create(block: ExtensionViewHolder<T>.() -> Unit) = CreateItemDelegate(this, block)

fun <T> ExtensionItemDelegate<T>.bind(block: ExtensionViewHolder<T>.(item: T) -> Unit) = BindItemDelegate(this, block)

fun <T> ExtensionItemDelegate<T>.bindPayloads(block: ExtensionViewHolder<T>.(item: T, payloads: List<Any>) -> Unit) = BindPayloadsItemDelegate(this, block)

fun <T> ExtensionItemDelegate<T>.click(clickListener: (T) -> Unit) = ClickableItemDelegate(this, clickListener)

fun <T> ExtensionItemDelegate<T>.clickWithPos(clickListener: (T, Int) -> Unit) = ClickableWithPosItemDelegate(this, clickListener)