namespace SHH.CameraSdk;

/// <summary>
/// [管理层] 视频源总控管理器 (V3.5 持久化集成版)
/// 核心职责：统一管理所有相机设备的生命周期、状态监控与资源清理，对接协调器实现自动自愈
/// </summary>
public class CameraManager : IDisposable, IAsyncDisposable
{
    #region --- 1. 核心资源与状态 (Fields & States) ---

    /// <summary> 全局设备实例池（线程安全），Key = 设备唯一标识 </summary>
    private readonly ConcurrentDictionary<long, BaseVideoSource> _cameraPool = new();

    /// <summary> 后台协调器实例：负责心跳检测、断线重连、僵尸流恢复 </summary>
    private readonly CameraCoordinator _coordinator = new();

    /// <summary> 全局取消令牌源：用于销毁时瞬间关停所有异步扫描任务 </summary>
    private readonly CancellationTokenSource _globalCts = new();

    /// <summary> 销毁状态标记：防止重复销毁或销毁过程中执行操作 </summary>
    private volatile bool _isDisposed;

    /// <summary> 
    /// 协调器引擎运行状态标记
    /// 使用 volatile 关键字确保多线程环境下的内存可见性
    /// </summary>
    private volatile bool _isEngineStarted = false;

    // [新增] 存储服务引用
    private readonly IStorageService _storage;

    #endregion

    #region --- 构造函数 (Constructor) ---

    // [修改] 注入 IStorageService
    public CameraManager(IStorageService storage)
    {
        _storage = storage;
    }

    #endregion

    #region --- 2. 设备管理 (Device Management) ---

    /// <summary>
    /// 向管理池添加新相机设备
    /// </summary>
    /// <param name="config">相机设备配置信息</param>
    public void AddDevice(VideoSourceConfig config)
    {
        // [安全防护] 销毁过程中禁止添加新设备
        if (_isDisposed) return;

        // 使用工厂方法创建
        var device = CreateDeviceInstance(config);

        if (!_cameraPool.TryAdd(config.Id, device))
        {
            // 如果添加失败（ID冲突），由于 device 还没被使用，直接释放掉
            device.DisposeAsync().AsTask().Wait();
            throw new InvalidOperationException($"设备 ID {config.Id} 已存在");
        }

        // 动态激活逻辑：引擎已启动时，新设备直接标记为运行状态
        if (_isEngineStarted)
        {
            device.IsRunning = true;
        }

        // [新增] 自动保存到文件
        SaveChanges();
    }

    /// <summary>
    /// 根据设备ID获取指定的视频源实例
    /// </summary>
    public BaseVideoSource? GetDevice(long id)
        => _cameraPool.TryGetValue(id, out var source) ? source : null;

    /// <summary>
    /// 获取当前管理的所有相机设备
    /// </summary>
    public IEnumerable<BaseVideoSource> GetAllDevices()
    {
        return _cameraPool.Values.ToList();
    }

    /// <summary>
    /// [修改] 异步移除设备 (从 RemoveDevice 改为 RemoveDeviceAsync)
    /// </summary>
    public async Task RemoveDeviceAsync(long id)
    {
        if (_cameraPool.TryRemove(id, out var device))
        {
            // 记录日志
            Console.WriteLine($"[Manager] 正在移除设备 {id}...");

            // 1. 停止物理连接
            await device.StopAsync();

            // 2. 释放资源
            await device.DisposeAsync();

            Console.WriteLine($"[Manager] 设备 {id} 已彻底移除");

            // [新增] 自动保存到文件
            SaveChanges();
        }
    }

    // 为了兼容旧代码保留同步方法，但不推荐使用
    public void RemoveDevice(long id) => RemoveDeviceAsync(id).Wait();

    #endregion

    #region --- 3. 生命周期控制 (Engine Lifecycle) ---

    /// <summary>
    /// 启动视频管理引擎，加载配置，初始化SDK并启动协调器自愈循环
    /// </summary>
    public async Task StartAsync()
    {
        if (_isDisposed) throw new ObjectDisposedException(nameof(CameraManager));
        if (_isEngineStarted) return;

        // =========================================================
        // 1. [新增] 从文件加载设备配置
        // =========================================================
        try
        {
            Console.WriteLine("[Manager] 正在检查本地配置文件...");
            var savedConfigs = await _storage.LoadDevicesAsync();

            int loadedCount = 0;
            foreach (var config in savedConfigs)
            {
                // 防止ID冲突（虽然文件里理论上不重复）
                if (!_cameraPool.ContainsKey(config.Id))
                {
                    var device = CreateDeviceInstance(config);
                    // 默认设为运行状态，让协调器稍后去连接
                    device.IsRunning = true;
                    _cameraPool.TryAdd(config.Id, device);
                    loadedCount++;
                }
            }
            if (loadedCount > 0)
                Console.WriteLine($"[Manager] 已从文件恢复 {loadedCount} 台设备配置");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"[Manager] 加载配置文件警告: {ex.Message}");
        }

        // =========================================================
        // 2. 全局驱动环境预初始化
        // =========================================================
        HikSdkManager.Initialize();

        // 标记引擎启动状态
        _isEngineStarted = true;

        // =========================================================
        // 3. 启动协调器后台自愈循环
        // =========================================================
        _ = Task.Factory.StartNew(
            () => _coordinator.RunCoordinationLoopAsync(_globalCts.Token),
            _globalCts.Token,
            TaskCreationOptions.LongRunning,
            TaskScheduler.Default);

        // 这里传递 _cameraPool 给协调器（如果协调器是独立引用的，可能需要 Register 逻辑，
        // 但根据您的代码，协调器似乎是依赖外部注册或共享引用的。
        // *注意*：如果 Coordinator 需要显式注册，请在这里补上：
        foreach (var dev in _cameraPool.Values) _coordinator.Register(dev);

        Console.WriteLine($"[CameraManager] 引擎启动成功，当前管理 {_cameraPool.Count} 路相机设备。");
        await Task.CompletedTask;
    }

    /// <summary>
    /// 获取当前所有相机的全局状态简报
    /// </summary>
    public IEnumerable<(long Id, string Ip, VideoSourceStatus Status)> GetGlobalStatus()
    {
        return _cameraPool.Values.Select(v => (v.Id, v.Config.IpAddress, v.Status));
    }

    #endregion

    #region --- 4. 监控数据采集 (Telemetry Collection) ---

    /// <summary>
    /// 获取所有相机的健康度报告
    /// </summary>
    public IEnumerable<CameraHealthReport> GetDetailedTelemetry()
    {
        return _cameraPool.Values.Select(cam => new CameraHealthReport
        {
            DeviceId = cam.Id,
            Ip = cam.Config.IpAddress,
            Status = cam.Status.ToString(),
            LastError = cam.Status == VideoSourceStatus.Faulted ? "设备故障或网络中断" : "运行正常"
        });
    }

    /// <summary>
    /// 获取全量相机实时遥测数据快照 (MonitorController 使用)
    /// </summary>
    public IEnumerable<CameraTelemetryInfo> GetTelemetrySnapshot()
    {
        return _cameraPool.Values.Select(cam =>
        {
            // 健康度评分算法
            int healthScore = 100;
            if (cam.Status == VideoSourceStatus.Faulted)
                healthScore = 0;
            else if (cam.Status == VideoSourceStatus.Reconnecting)
                healthScore = 60;
            else if (cam.RealFps < 1.0 && cam.Status == VideoSourceStatus.Playing)
                healthScore = 40;

            return new CameraTelemetryInfo
            {
                DeviceId = cam.Id,
                Name = cam.Config.Name,
                IpAddress = cam.Config.IpAddress,
                Status = cam.Status.ToString(),
                IsOnline = cam.IsPhysicalOnline,
                Fps = cam.RealFps,
                Bitrate = cam.RealBitrate,
                TotalFrames = cam.TotalFrames,
                HealthScore = healthScore,
                LastErrorMessage = cam.Status == VideoSourceStatus.Faulted ? "设备故障或网络中断" : null,
                Timestamp = DateTime.Now,
                Width = cam.Width,
                Height = cam.Height,
            };
        }).ToList();
    }

    #endregion

    #region --- 5. 配置热更新 (Config Hot Update) ---

    /// <summary>
    /// 智能更新设备配置 (含冷热分离逻辑)
    /// </summary>
    public async Task UpdateDeviceConfigAsync(long deviceId, DeviceUpdateDto dto)
    {
        if (!_cameraPool.TryGetValue(deviceId, out var device))
            throw new KeyNotFoundException($"设备 {deviceId} 不存在");

        // 1. 审计
        device.AddAuditLog("收到配置更新请求");

        // 2. 创建副本进行对比
        var oldConfig = device.Config;
        var newConfig = oldConfig.DeepCopy();

        // 3. 映射 DTO 值
        if (dto.IpAddress != null) newConfig.IpAddress = dto.IpAddress;
        if (dto.Port != null) newConfig.Port = dto.Port.Value;
        if (dto.Username != null) newConfig.Username = dto.Username;
        if (dto.Password != null) newConfig.Password = dto.Password;
        if (dto.ChannelIndex != null) newConfig.ChannelIndex = dto.ChannelIndex.Value;
        if (dto.StreamType != null) newConfig.StreamType = dto.StreamType.Value;
        if (dto.Name != null) newConfig.Name = dto.Name;
        if (dto.RenderHandle != null) newConfig.RenderHandle = (IntPtr)dto.RenderHandle.Value;
        if (dto.Brand != null) newConfig.Brand = (DeviceBrand)dto.Brand;

        // 4. 判定冷热更新
        bool needColdRestart =
            newConfig.IpAddress != oldConfig.IpAddress ||
            newConfig.Port != oldConfig.Port ||
            newConfig.Username != oldConfig.Username ||
            newConfig.Password != oldConfig.Password ||
            newConfig.ChannelIndex != oldConfig.ChannelIndex ||
            newConfig.Brand != oldConfig.Brand;

        if (needColdRestart)
        {
            device.AddAuditLog($"检测到核心参数变更，执行冷重启 (Reboot)");
            bool wasRunning = device.IsRunning;

            // A. 彻底停止
            if (device.IsOnline) await device.StopAsync();

            // B. 写入新配置
            device.UpdateConfig(newConfig);

            // C. 自动重启
            if (wasRunning) await device.StartAsync();
        }
        else
        {
            device.AddAuditLog($"检测到运行时参数变更，执行热更新 (HotSwap)");

            // A. 更新配置数据
            device.UpdateConfig(newConfig);

            // B. 在线应用策略
            if (device.IsOnline)
            {
                var options = new DynamicStreamOptions
                {
                    StreamType = dto.StreamType,
                    RenderHandle = dto.RenderHandle.HasValue ? (IntPtr)dto.RenderHandle : null
                };
                device.ApplyOptions(options);
            }
        }

        // [新增] 保存文件
        SaveChanges();
    }

    /// <summary>
    /// 全量替换更新 (兼容接口)
    /// </summary>
    public async Task UpdateDeviceAsync(int id, VideoSourceConfig newConfig)
    {
        if (!_cameraPool.TryGetValue(id, out var oldDevice))
            throw new KeyNotFoundException($"设备 #{id} 不存在");

        bool wasRunning = oldDevice.IsRunning ||
                          oldDevice.Status == VideoSourceStatus.Playing ||
                          oldDevice.Status == VideoSourceStatus.Connecting;

        Console.WriteLine($"[Manager] 正在更新设备 #{id}，配置变更中...");

        try
        {
            await oldDevice.StopAsync();
            await oldDevice.DisposeAsync();
        }
        catch (Exception ex)
        {
            Console.WriteLine($"[Manager] 销毁旧设备时警告: {ex.Message}");
        }

        var newDevice = CreateDeviceInstance(newConfig);
        _cameraPool[id] = newDevice;

        Console.WriteLine($"[Manager] 设备 #{id} 实例已重建。");

        if (wasRunning)
        {
            await newDevice.StartAsync();
        }

        // [新增] 保存文件
        SaveChanges();
    }

    #endregion

    #region --- 6. 资源清理 (Disposal) ---

    public void Dispose() => DisposeAsync().AsTask().GetAwaiter().GetResult();

    public async ValueTask DisposeAsync()
    {
        if (_isDisposed) return;
        _isDisposed = true;
        _isEngineStarted = false;

        try
        {
            _globalCts.Cancel();

            var devices = _cameraPool.Values.ToArray();
            _cameraPool.Clear();

            var disposeTasks = devices.Select(async device =>
            {
                try { await device.DisposeAsync(); }
                catch { }
            });
            await Task.WhenAll(disposeTasks);

            try
            {
                HikSdkManager.Uninitialize();
            }
            catch { }
        }
        finally
        {
            _globalCts.Dispose();
        }
    }

    #endregion

    #region --- 7. 内部辅助 (Helpers) ---

    private BaseVideoSource CreateDeviceInstance(VideoSourceConfig config)
    {
        return config.Brand switch
        {
            DeviceBrand.HikVision => new HikVideoSource(config),
            _ => throw new NotSupportedException($"不支持的设备品牌: {config.Brand}")
        };
    }

    /// <summary>
    /// [新增] 触发异步保存 (Fire-and-Forget)
    /// 不阻塞当前 API 线程，让后台存储服务去排队写入
    /// </summary>
    private void SaveChanges()
    {
        try
        {
            var allConfigs = _cameraPool.Values.Select(d => d.Config).ToList();
            // 异步调用存储服务，不使用 await 以免阻塞 API 响应
            _ = _storage.SaveDevicesAsync(allConfigs);
        }
        catch (Exception ex)
        {
            Console.WriteLine($"[Manager] 触发保存失败: {ex.Message}");
        }
    }

    #endregion
}