package nl.astraeus.nl.astraeus.persistence.reference

import nl.astraeus.nl.astraeus.persistence.Persistable
import nl.astraeus.nl.astraeus.persistence.currentTransaction
import java.io.Serializable
import kotlin.reflect.KProperty

inline fun <reified T : Persistable> reference(
  initialValue:T
) = Reference(T::class.java, initialValue)

inline fun <reified T : Persistable> nullableReference(
  initialValue:T? = null
) = NullableReference(T::class.java, initialValue)

class Reference<S : Persistable>(
  val cls: Class<S>,
  initialValue: S
) : Serializable {
  var id: Long = initialValue.id

  operator fun getValue(thisRef: Persistable, property: KProperty<*>): S {
    return currentTransaction()?.find(cls.kotlin, id) ?: throw IllegalStateException("Reference not found")
  }

  operator fun setValue(thisRef: Persistable, property: KProperty<*>, value: S) {
    currentTransaction()?.store(value)
    id = value.id
  }

  companion object {
    private const val serialVersionUID: Long = 1L
  }
}

class NullableReference<S : Persistable>(
  val cls: Class<S>,
  initialValue: S? = null
) : Serializable {
  var id: Long? = initialValue?.id

  operator fun getValue(thisRef: Persistable, property: KProperty<*>): S? {
    return currentTransaction()?.find(cls.kotlin, id ?: 0L)
  }

  operator fun setValue(thisRef: Persistable, property: KProperty<*>, value: S?) {
    if (value != null) {
      // todo: only store if not already stored?
      currentTransaction()?.store(value)
    }
    id = value?.id
  }

  companion object {
    private const val serialVersionUID: Long = 1L
  }
}