using MessagePack;
using Microsoft.Extensions.Hosting;
using NetMQ;
using NetMQ.Sockets;
using SHH.CameraSdk;
using SHH.Contracts;
using System.Text;

namespace SHH.CameraService;

public class CommandClientWorker : BackgroundService
{
    private readonly ServiceConfig _config;
    private readonly CommandDispatcher _dispatcher;
    private readonly InterceptorPipeline _pipeline;

    // 管理多个 Socket
    private readonly List<DealerSocket> _sockets = new();
    private NetMQPoller? _poller;

    public CommandClientWorker(
        ServiceConfig config,
        CommandDispatcher dispatcher,
        InterceptorPipeline pipeline)
    {
        _config = config;
        _dispatcher = dispatcher;
        _pipeline = pipeline;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        await Task.Yield();

        if (!_config.ShouldConnect || _config.CommandEndpoints.Count == 0) return;

        // 1. 建立连接 (但不立即启动 Poller)
        _poller = new NetMQPoller();

        foreach (var ep in _config.CommandEndpoints)
        {
            try
            {
                var socket = new DealerSocket();
                // 建议加上 Socket 索引或 UUID 以防服务端认为 Identity 冲突
                // 或者保持原样，取决于服务端逻辑。通常同一个 AppId 连不同 Server 是没问题的。
                socket.Options.Identity = Encoding.UTF8.GetBytes(_config.AppId);
                socket.Connect(ep.Uri);

                socket.ReceiveReady += OnSocketReceiveReady;

                _sockets.Add(socket);
                _poller.Add(socket);

                Console.WriteLine($"[指令] 建立通道: {ep.Uri}");
            }
            catch (Exception ex) { Console.WriteLine($"[指令] 连接异常: {ex.Message}"); }
        }

        if (_sockets.Count == 0) return;

        // =================================================================
        // 2. 发送注册包 (在 Poller 启动前发送，绝对线程安全)
        // =================================================================
        var registerPayload = new RegisterPayload
        {
            Protocol = ProtocolHeaders.ServerRegister,
            InstanceId = _config.AppId,
            ProcessId = Environment.ProcessId,
            Version = "1.0.0",
            ServerIp = "127.0.0.1",
            WebApiPort = _config.BasePort,
            StartTime = DateTime.Now
        };

        try
        {
            byte[] regData = MessagePackSerializer.Serialize(registerPayload);
            var ctx = await _pipeline.ExecuteSendAsync(ProtocolHeaders.ServerRegister, regData);

            if (ctx != null)
            {
                foreach (var socket in _sockets)
                {
                    // 此时 Poller 还没跑，主线程发送是安全的
                    socket.SendMoreFrame(ctx.Protocol).SendFrame(ctx.Data);
                }
                Console.WriteLine($"[指令] 注册包已广播至 {_sockets.Count} 个目标");
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"[指令] 注册失败: {ex.Message}");
        }

        // =================================================================
        // 3. 绑定 ACK 逻辑
        // =================================================================
        // 关键修正：直接使用 async void，不要包裹在 Task.Run 中！
        // 因为 OnResponseReady 是由 Dispatcher 触发的，而 Dispatcher 是由 Poller 线程触发的。
        // 所以这里就在 Poller 线程内，可以直接操作 Socket。
        _dispatcher.OnResponseReady += async (result) =>
        {
            try
            {
                byte[] resultBytes = MessagePackSerializer.Serialize(result);
                var ctx = await _pipeline.ExecuteSendAsync(ProtocolHeaders.CommandResult, resultBytes);

                if (ctx != null)
                {
                    foreach (var socket in _sockets)
                    {
                        socket.SendMoreFrame(ctx.Protocol).SendFrame(ctx.Data);
                    }
                    Console.WriteLine($"[指令] ACK 已广播 (ID: {result.RequestId})");
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"[ACK] 发送失败: {ex.Message}");
            }
        };

        // =================================================================
        // 4. 启动 Poller (开始监听接收)
        // =================================================================
        _poller.RunAsync();

        // 阻塞直到取消
        while (!stoppingToken.IsCancellationRequested)
        {
            await Task.Delay(1000, stoppingToken);
        }

        // 清理
        _poller.Stop();
        _poller.Dispose();
        foreach (var s in _sockets) s.Dispose();
    }

    private async void OnSocketReceiveReady(object? sender, NetMQSocketEventArgs e)
    {
        // 这里的代码运行在 Poller 线程
        NetMQMessage incomingMsg = new NetMQMessage();
        if (e.Socket.TryReceiveMultipartMessage(ref incomingMsg))
        {
            if (incomingMsg.FrameCount >= 2)
            {
                try
                {
                    string rawProtocol = incomingMsg[0].ConvertToString();
                    byte[] rawData = incomingMsg[1].ToByteArray();

                    var ctx = await _pipeline.ExecuteReceiveAsync(rawProtocol, rawData);
                    if (ctx != null)
                    {
                        // DispatchAsync 会同步触发 OnResponseReady，
                        // 从而在同一个线程内完成 ACK 发送，线程安全且高效。
                        await _dispatcher.DispatchAsync(ctx.Protocol, ctx.Data);
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"[指令] 处理异常: {ex.Message}");
                }
            }
        }
    }
}