import android.content.SharedPreferences
import kotlin.properties.ReadWriteProperty
import kotlin.reflect.KFunction3
import kotlin.reflect.KProperty

@Suppress("UNCHECKED_CAST")
fun <T> sharedPreferences(sharedPreferences: SharedPreferences, key: String, defaultValue: T): SharedPreferencesProperty<T> =
        when (defaultValue) {
            is Boolean -> SharedPreferencesProperty(sharedPreferences, key, defaultValue,
                    SharedPreferences::getBoolean, SharedPreferences.Editor::putBoolean)
                    as SharedPreferencesProperty<T>

            is Float -> SharedPreferencesProperty(sharedPreferences, key, defaultValue,
                    SharedPreferences::getFloat, SharedPreferences.Editor::putFloat)
                    as SharedPreferencesProperty<T>

            is Int -> SharedPreferencesProperty(sharedPreferences, key, defaultValue,
                    SharedPreferences::getInt, SharedPreferences.Editor::putInt)
                    as SharedPreferencesProperty<T>

            is Long -> SharedPreferencesProperty(sharedPreferences, key, defaultValue,
                    SharedPreferences::getLong, SharedPreferences.Editor::putLong)
                    as SharedPreferencesProperty<T>

            is String -> SharedPreferencesProperty(sharedPreferences, key, defaultValue,
                    SharedPreferences::getString, SharedPreferences.Editor::putString)
                    as SharedPreferencesProperty<T>

            is Set<*> -> SharedPreferencesProperty(sharedPreferences, key, defaultValue as Set<String>,
                    SharedPreferences::getStringSet, SharedPreferences.Editor::putStringSet)
                    as SharedPreferencesProperty<T>

            else -> throw IllegalStateException("Illegal property type: ${(defaultValue as Any).javaClass}")
        }

open class SharedPreferencesProperty<T>(
        private val sharedPreferences: SharedPreferences,
        val key: String,
        val defaultValue: T,
        val getValue: KFunction3<SharedPreferences, String, T, T>,
        val setValue: KFunction3<SharedPreferences.Editor, String, T, SharedPreferences.Editor>)
    : ReadWriteProperty<Any, T> {

    override fun getValue(thisRef: Any, property: KProperty<*>): T =
            getValue(sharedPreferences, key, defaultValue)

    override fun setValue(thisRef: Any, property: KProperty<*>, value: T) =
            setValue(sharedPreferences.edit(), key, value).apply()
}