StateVO.kt

@file:Suppress("UNCHECKED_CAST", "NOTHING_TO_INLINE")

package kore.vo

import androidx.compose.runtime.*
import androidx.compose.runtime.saveable.Saver
import androidx.compose.runtime.saveable.mapSaver
import androidx.compose.runtime.saveable.rememberSaveable
import kotlin.reflect.KClass
import kotlin.reflect.KProperty1

abstract class StateVO<T:StateVO<T>>:VO(){
    companion object{
        @Composable
        inline operator fun <reified T:StateVO<T>> invoke(block:T.()->Unit):T{
            val toggle = rememberSaveable{mutableStateOf(true)}
            val modelState = rememberSaveable(stateSaver = saver(T::class)){mutableStateOf(null)}
            val model = modelState.value ?: T::class.java.getDeclaredConstructor().newInstance().init(modelState as MutableState<T?>, block)

            model.stateToggle = toggle
            toggle.value
            return model as T
        }
        @PublishedApi internal val savers = hashMapOf<KClass<out StateVO<*>>, Saver<StateVO<*>?, Any>>()
        @PublishedApi internal inline fun saver(type:KClass<out StateVO<*>>):Saver<StateVO<*>?, Any> = savers.getOrPut(type) {
            mapSaver({it?.props ?: emptyMap()}){
                type.java.getDeclaredConstructor().newInstance().apply{
                    (props as HashMap<String, Any?>).putAll(it)
                    stateToggle?.value = stateToggle?.value != true
                }
            }
        }
    }
    @PublishedApi internal var stateToggle:MutableState<Boolean>? = null
    inline fun init(model:MutableState<T?>, block:T.()->Unit = {}):T
    = (this as T).also{
        block()
        model.value = it
    }
    final override fun afterSet(key:String, value:Any){
        stateToggle?.value = stateToggle?.value != true
    }
    class StateValue<V>(private val vo:StateVO<*>, private val prop:String){
        operator fun invoke(value:V){
            vo[prop] = value as Any
        }
        operator fun invoke():V = vo[prop] as V
        @get:Composable
        val state:State<V> get() = rememberUpdatedState(vo[prop] as V)

    }
    inline fun <V> value(prop:KProperty1<T, V>):StateValue<V>
    = StateValue(this, prop.name)
    @Composable
    inline fun <V> state(prop:KProperty1<T, V>):State<V>
    = rememberUpdatedState(this[prop.name] as V)
}