//
//  ArpServer.swift
//  sdlan
//
//  Created by 安礼成 on 2025/7/14.
//
import Foundation
import Darwin

final class ArpServer {
    private var known_macs: [UInt32:Data] = [:]
    private var lock = os_unfair_lock()
    
    init(known_macs: [UInt32:Data]) {
        self.known_macs = known_macs
    }
    
    func query(ip: UInt32) -> Data? {
        return withLock {
            return self.known_macs[ip]
        }
    }
    
    func append(ip: UInt32, mac: Data) {
        withLock {
            self.known_macs[ip] = mac
        }
    }
    
    func remove(ip: UInt32) {
        withLock {
            _ = self.known_macs.removeValue(forKey: ip)
        }
    }
    
    func clear() {
        withLock {
            self.known_macs = [:]
        }
    }
    
    private func withLock<T>(_ body: () throws -> T) rethrows -> T {
        os_unfair_lock_lock(&lock)
        defer{
            os_unfair_lock_unlock(&lock)
        }
        
        return try body()
    }
    
}