//
//  SDLNoticeClient.swift
//  Tun
//
//  Created by 安礼成 on 2024/5/20.
//

import Foundation

//
//  SDLanServer.swift
//  Tun
//
//  Created by 安礼成 on 2024/1/31.
//

import Foundation
import NIOCore
import NIOPosix

// 处理和sn-server服务器之间的通讯
class SDLNoticeClient: ChannelInboundHandler {
    public typealias InboundIn = AddressedEnvelope<ByteBuffer>
    public typealias OutboundOut = AddressedEnvelope<ByteBuffer>
    
    private var thread: Thread?
    var context: ChannelHandlerContext?
    private let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
    private let remoteAddress: SocketAddress
    
    init() {
        self.remoteAddress = try! SocketAddress(ipAddress: "127.0.0.1", port: 50195)
    }
    
    // 启动函数
    func start() {
        self.thread = Thread {
            let bootstrap = DatagramBootstrap(group: self.group)
                .channelOption(ChannelOptions.socketOption(.so_reuseaddr), value: 1)
                .channelInitializer { channel in
                    // 接收缓冲区
                    channel.pipeline.addHandler(self)
                }
            
            let channel = try! bootstrap.bind(host: "0.0.0.0", port: 0).wait()
            SDLLogger.log("[SDLNoticeClient] started and listening on: \(channel.localAddress!)", level: .debug)
            
            // This will never unblock as we don't close the channel
            try! channel.closeFuture.wait()
        }
        self.thread?.start()
    }
    
    // -- MARK: ChannelInboundHandler Methods
    
    public func channelActive(context: ChannelHandlerContext) {
        self.context = context
    }
    
    // 接收到的消息, 消息需要根据类型分流
    public func channelRead(context: ChannelHandlerContext, data: NIOAny) {
        context.fireChannelRead(data)
    }
    
    public func errorCaught(context: ChannelHandlerContext, error: Error) {
        // As we are not really interested getting notified on success or failure we just pass nil as promise to
        // reduce allocations.
        context.close(promise: nil)
        self.context = nil
    }
    
    public func channelInactive(context: ChannelHandlerContext) {
        self.context = nil
        context.close(promise: nil)
    }
    
    // 处理写入逻辑
    func send(data: Data) {
        guard let context = self.context else {
            return
        }
        
        context.eventLoop.execute {
            let buffer = context.channel.allocator.buffer(bytes: data)
            
            let envelope = AddressedEnvelope<ByteBuffer>(remoteAddress: self.remoteAddress, data: buffer)
            context.writeAndFlush(self.wrapOutboundOut(envelope), promise: nil)
        }
    }
    
    deinit {
        self.thread?.cancel()
        try? self.group.syncShutdownGracefully()
    }
}