//
//  SDLContext.swift
//  Tun
//
//  Created by 安礼成 on 2024/2/29.
//

import Foundation
import NetworkExtension
import NIOCore
import Combine

// 上下文环境变量，全局共享
/*
1. 处理rsa的加解密逻辑
 */

actor SDLTunnelProviderActor {
    
    // 路由信息
    struct Route {
        let dstAddress: String
        let subnetMask: String
        
        var debugInfo: String {
            return "\(dstAddress):\(subnetMask)"
        }
    }
    
    // 数据包读取任务
    private var readTask: Task<(), Never>?
    
    let provider: NEPacketTunnelProvider
    let logger: SDLLogger
    
    public init(provider: NEPacketTunnelProvider, logger: SDLLogger) {
        self.logger = logger
        self.provider = provider
    }
    
    func writePackets(packets: [NEPacket]) {
        //let packet = NEPacket(data: ipPacket.data, protocolFamily: 2)
        self.provider.packetFlow.writePacketObjects(packets)
    }
    
    // 网络改变时需要重新配置网络信息
    func setNetworkSettings(devAddr: SDLDevAddr, dnsServer: String) async throws {
        let netAddress = SDLNetAddress(ip: devAddr.netAddr, maskLen: UInt8(devAddr.netBitLen))
        let routes = [
            Route(dstAddress: netAddress.networkAddress, subnetMask: netAddress.maskAddress),
            Route(dstAddress: dnsServer, subnetMask: "255.255.255.255")
        ]
        
        // Add code here to start the process of connecting the tunnel.
        let networkSettings = NEPacketTunnelNetworkSettings(tunnelRemoteAddress: "8.8.8.8")
        networkSettings.mtu = 1460
        
        // 设置网卡的DNS解析
        
        let networkDomain = devAddr.networkDomain
        let dnsSettings = NEDNSSettings(servers: [dnsServer])
        dnsSettings.searchDomains = [networkDomain]
        dnsSettings.matchDomains = [networkDomain]
        dnsSettings.matchDomainsNoSearch = false
        networkSettings.dnsSettings = dnsSettings
        self.logger.log("[SDLContext] Tun started at network ip: \(netAddress.ipAddress), mask: \(netAddress.maskAddress)", level: .info)
        
        let ipv4Settings = NEIPv4Settings(addresses: [netAddress.ipAddress], subnetMasks: [netAddress.maskAddress])
        // 设置路由表
        //NEIPv4Route.default()
        ipv4Settings.includedRoutes = routes.map { route in
            NEIPv4Route(destinationAddress: route.dstAddress, subnetMask: route.subnetMask)
        }
        networkSettings.ipv4Settings = ipv4Settings
        // 网卡配置设置必须成功
        try await self.provider.setTunnelNetworkSettings(networkSettings)
    }
    
    // 开始读取数据, 用单独的线程处理packetFlow
    func readPackets() async -> [Data] {
        let (packets, numbers) = await self.provider.packetFlow.readPackets()
        return zip(packets, numbers).compactMap { (data, number) in
            return number == 2 ? data : nil
        }
    }
    
}