//
//  PolicySnapshot.swift
//  Tun
//
//  Created by Codex on 2026/5/20.
//

import Foundation

final class PolicySnapshot: Snapshot {
    private let policyRuleSnapshot: PolicyRuleSnapshot

    init(policyRuleSnapshot: PolicyRuleSnapshot) {
        self.policyRuleSnapshot = policyRuleSnapshot
    }

    func allows(srcIdentityID: UInt32, ipPacket: IPPacket) -> Bool {
        let ruleMap = self.policyRuleSnapshot.lookup(srcIdentityID)
        let proto = ipPacket.header.proto

        switch ipPacket.transportPacket {
        case .tcp(let tcpPacket):
            return ruleMap?.isAllow(proto: proto, port: tcpPacket.header.dstPort) ?? false
        case .udp(let udpPacket):
            return ruleMap?.isAllow(proto: proto, port: udpPacket.dstPort) ?? false
        case .icmp:
            return true
        default:
            return false
        }
    }

    static func empty() -> PolicySnapshot {
        return PolicySnapshot(policyRuleSnapshot: .empty())
    }
}