ValueChangeDelegate.kt

/*
 * Copyright (c) 2021 JayaKrishnan Nair K
 * All rights reserved.
 */

package tech.jknair.uibase.utils

import kotlin.properties.ObservableProperty
import kotlin.properties.ReadWriteProperty
import kotlin.reflect.KProperty

abstract class ValueChangeDelegate<V>(
    initialValue: V,
    private val distinct: Boolean = false
) : ObservableProperty<V>(initialValue) {

    override fun beforeChange(property: KProperty<*>, oldValue: V, newValue: V): Boolean {
        return !distinct || oldValue != newValue
    }

}

inline fun <V> valueChange(
    distinct: Boolean = false,
    initialValue: V,
    crossinline onChangeCallback: (newValue: V) -> Unit
): ReadWriteProperty<Nothing, V> {
    return object: ValueChangeDelegate<V>(initialValue) {

        override fun afterChange(property: KProperty<*>, oldValue: V, newValue: V) {
            onChangeCallback(newValue)
        }

    }
}

inline fun <V> valueChange(
    initialValue: V,
    crossinline onChangeCallback: (newValue: V) -> Unit
): ReadWriteProperty<Nothing, V> {
    return object: ValueChangeDelegate<V>(initialValue) {

        override fun afterChange(property: KProperty<*>, oldValue: V, newValue: V) {
            onChangeCallback(newValue)
        }

    }
}