using System.Windows;
using System.Windows.Media.Imaging;
using SHH.CameraDashboard.Services; // 引用服务命名空间

namespace SHH.CameraDashboard;

public class VideoTileViewModel : ViewModelBase
{
    private readonly string _boundCameraId;

    // --- 属性定义 ---
    private string _cameraName;
    public string CameraName
    {
        get => _cameraName;
        set { _cameraName = value; OnPropertyChanged(); }
    }

    private string _statusInfo;
    public string StatusInfo
    {
        get => _statusInfo;
        set { _statusInfo = value; OnPropertyChanged(); }
    }

    private BitmapImage _videoSource;
    public BitmapImage VideoSource
    {
        get => _videoSource;
        set { _videoSource = value; OnPropertyChanged(); }
    }

    // --- 构造函数 ---
    public VideoTileViewModel(string cameraId, string name)
    {
        _boundCameraId = cameraId;
        CameraName = name;
        StatusInfo = "等待信号...";

        // 【修正 1】直接订阅单例服务
        // 不需要判断 null，因为 Instance 是静态初始化的，永远存在
        StreamReceiverService.Instance.OnFrameReceived += OnGlobalFrameReceived;
    }

    // --- 事件回调 (后台线程) ---
    private void OnGlobalFrameReceived(string cameraId, byte[] jpgData)
    {
        // 1. 过滤：不是我的画面，直接忽略
        if (cameraId != _boundCameraId) return;

        // 2. 解码：耗时操作在后台完成
        var bitmap = BitmapHelper.ToBitmapImage(jpgData);
        if (bitmap == null) return;

        // 3. 【修正 2】恢复 UI 更新逻辑
        // 必须使用 Dispatcher，因为 VideoSource 绑定在界面上，只能在主线程修改
        Application.Current.Dispatcher.InvokeAsync(() =>
        {
            VideoSource = bitmap;

            // 更新状态信息 (例如显示当前时间和数据大小)
            StatusInfo = $"{DateTime.Now:HH:mm:ss} | {jpgData.Length / 1024} KB";
        });
    }

    // --- 资源清理 ---
    public void Unload()
    {
        // 【修正 3】从单例服务取消订阅
        // 这一步至关重要，否则切换页面时会内存泄漏
        StreamReceiverService.Instance.OnFrameReceived -= OnGlobalFrameReceived;

        // 清空图片引用，帮助 GC 回收内存
        VideoSource = null;
    }
}