@file:OptIn(ExperimentalContracts::class)

package ru.landrafhomyak.utility.reference_counter

import kotlin.contracts.ExperimentalContracts
import kotlin.contracts.InvocationKind
import kotlin.contracts.contract
import kotlin.jvm.JvmName
import ru.landgrafhomyak.utility.highlevel_try_finally.safeAutoClose1
import ru.landgrafhomyak.utility.highlevel_try_finally.safeAutoClose2

public sealed class MayBeClosedReferenceCounter {
	private val _value: _AtomicLong
	private val _errMessageClosed: String

	protected constructor(errMessageClosed: String) {
		_Platform.jvm_assertNotNull(errMessageClosed, "param: errMessageClosed")
		this._errMessageClosed = errMessageClosed
		this._value = _AtomicLong(0L)
	}

	@JvmName("throwClosed")
	public fun throwClosed() {
		throw IllegalStateException(this._errMessageClosed)
	}

	@JvmName("incref")
	public fun incref() {
		this._value.update { o ->
			if (o < 0) this.throwClosed()
			return@update o + 1
		}
	}

	@JvmName("tryIncref\$kt")
	public inline fun <R> tryIncref(block: () -> R): R {
		contract {
			callsInPlace(block, InvocationKind.EXACTLY_ONCE)
		}
		this.incref()
		return safeAutoClose2(onError = this::decref, action = block)
	}

	@JvmName("assertNotClosed")
	public fun assertNotClosed() {
		if (this._value.get() < 0) this.throwClosed()
	}

	@JvmName("decref")
	public fun decref() {
		this._value.update(Long::dec)
	}

	@JvmName("tryDecref\$kt")
	public inline fun <R> tryDecref(block: () -> R): R {
		contract {
			callsInPlace(block, InvocationKind.EXACTLY_ONCE)
		}
		this.assertNotClosed()
		return safeAutoClose2(onSuccess = this::decref, action = block)
	}

	@get:JvmName("isClosed")
	public val isClosed: Boolean get() = this._value.get() < 0

	@Suppress("INAPPLICABLE_JVM_NAME")
	@JvmName("close")
	protected open fun close(errExistRefs: String) {
		_Platform.jvm_assertNotNull(errExistRefs, "param: errExistRefs")
		val state = this._value.compareAndExchange(0, _Misc.CLOSED_STATE_VALUE)
		when {
			state > 0 -> throw IllegalStateException(errExistRefs)
			state < 0 -> this.throwClosed()
		}
	}

	@JvmName("withRef\$kt")
	public inline fun <R> withRef(protected: () -> R): R {
		this.incref()
		return safeAutoClose1(finally = this::decref, action = protected)
	}

	override fun toString(): String {
		val refcntCached = this._value.get()
		@Suppress("LiftReturnOrAssignment")
		if (refcntCached < 0)
			return "<ref counter [closed]>"
		else
			return "<ref counter [${refcntCached}]>"
	}
}