//
//  SnapshotPublisher.swift
//  punchnet
//
//  Created by 安礼成 on 2026/2/5.
//
import Atomics

final class SnapshotPublisher<S: Snapshot>: @unchecked Sendable {
    private let atomic: ManagedAtomic<Unmanaged<S>>
    
    init(initial snapshot: S) {
        self.atomic = ManagedAtomic(.passRetained(snapshot))
    }

    func publish(_ snapshot: S) {
        let newRef = Unmanaged.passRetained(snapshot)
        let oldRef = atomic.exchange(newRef, ordering: .releasing)
        oldRef.release()
    }

    @inline(__always)
    func current() -> S {
        atomic.load(ordering: .acquiring).takeUnretainedValue()
    }
    
    deinit {
        let ref = atomic.load(ordering: .acquiring)
        ref.release()
    }
    
}