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

namespace SHH.CameraService
{
    /// <summary>
    /// [二合一] 设备状态聚合与上报服务
    /// </summary>
    public class DeviceStateMonitorWorker : BackgroundService
    {
        private readonly CameraManager _manager;
        private readonly ServiceConfig _config;

        // ★ 2. 注入拦截器管道
        private readonly InterceptorPipeline _pipeline;

        // 本地状态全集缓存
        private readonly ConcurrentDictionary<string, StatusEventPayload> _stateStore = new();

        // 标记是否有新变更
        private volatile bool _isDirty = false;
        private long _lastSendTick = 0;

        // ★ 3. 构造函数增加 InterceptorPipeline 参数
        public DeviceStateMonitorWorker(
            CameraManager manager,
            ServiceConfig config,
            InterceptorPipeline pipeline) // <--- 注入点
        {
            _manager = manager;
            _config = config;
            _pipeline = pipeline;
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            // 1. 初始化缓存 (默认离线)
            foreach (var dev in _manager.GetAllDevices())
            {
                UpdateLocalState(dev.Id, false, "Init");
            }

            // 2. 挂载 SDK 事件
            _manager.OnDeviceStatusChanged += OnSdkStatusChanged;

            // 3. 建立连接
            var cmdEndpoint = _config.CommandEndpoints.FirstOrDefault()?.Uri;
            if (string.IsNullOrEmpty(cmdEndpoint))
            {
                Console.WriteLine("[StatusWorker] 警告: 未配置 Command 端点，状态上报无法启动。");
                return;
            }

            Console.WriteLine($"[StatusWorker] 启动状态上报，直连服务端: {cmdEndpoint}");

            using var socket = new DealerSocket();
            socket.Options.SendHighWatermark = 1000;
            // 设置 Identity 是个好习惯，虽然这里只发不收
            // socket.Options.Identity = ... 
            socket.Connect(cmdEndpoint);

            // 4. 定时循环 (1秒1次)
            var timer = new PeriodicTimer(TimeSpan.FromSeconds(1));
            try
            {
                while (await timer.WaitForNextTickAsync(stoppingToken))
                {
                    // ★ 4. 关键修正：必须使用 await 调用新的异步方法
                    await CheckAndDirectSendAsync(socket);
                }
            }
            finally
            {
                _manager.OnDeviceStatusChanged -= OnSdkStatusChanged;
                socket.Dispose();
            }
        }

        private void OnSdkStatusChanged(long deviceId, bool isOnline, string reason)
        {
            UpdateLocalState(deviceId, isOnline, reason);
            _isDirty = true;
        }

        private void UpdateLocalState(long deviceId, bool isOnline, string reason)
        {
            var evt = new StatusEventPayload
            {
                CameraId = deviceId.ToString(),
                IsOnline = isOnline,
                Reason = reason,
                Timestamp = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds()
            };
            _stateStore[deviceId.ToString()] = evt;
        }

        /// <summary>
        /// 检查并在当前线程直接发送 (已改为异步 Task)
        /// </summary>
        // ★ 5. 关键修正：void -> async Task
        private async Task CheckAndDirectSendAsync(NetMQSocket socket)
        {
            long now = Environment.TickCount64;
            // 策略: 有变更 或 超过5秒(心跳)
            bool shouldSend = _isDirty || (now - _lastSendTick > 5000);

            if (shouldSend)
            {
                try
                {
                    // A. 组包 (全量)
                    var snapshot = _stateStore.Values.ToList();
                    var batch = new StatusBatchPayload
                    {
                        Items = snapshot,
                        Timestamp = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds()
                    };

                    // B. 序列化
                    byte[] data = MessagePackSerializer.Serialize(batch);

                    // =========================================================
                    // ★ 6. 拦截器调用
                    // =========================================================
                    // 这里的 "STATUS_BATCH" 是协议头，你可以替换为 ProtocolHeaders.StatusBatch (如果定义了的话)
                    var ctx = await _pipeline.ExecuteSendAsync("STATUS_BATCH", data);

                    if (ctx != null) // 如果没被拦截
                    {
                        // C. 直接发送
                        socket.SendMoreFrame(ctx.Protocol)
                              .SendFrame(ctx.Data);

                        // D. 重置标记
                        _isDirty = false;
                        _lastSendTick = now;
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"[StatusWorker] 发送失败: {ex.Message}");
                }
            }
        }
    }
}