using System;
using System.Windows;
using System.Windows.Controls;
using Prism.Events;
using Prism.Ioc;
using XP.Hardware.Detector.Abstractions;
using XP.Hardware.Detector.Abstractions.Events;

namespace XP.Hardware.Detector.Views
{
    /// <summary>
    /// 面阵探测器配置视图 | Area detector configuration view
    /// 订阅探测器图像采集事件，将图像数据传递给直方图控件
    /// </summary>
    public partial class DetectorConfigView : UserControl
    {
        private IEventAggregator _eventAggregator;
        private SubscriptionToken _imageSubscriptionToken;

        public DetectorConfigView()
        {
            InitializeComponent();
            Loaded += OnLoaded;
            Unloaded += OnUnloaded;
        }

        /// <summary>
        /// 加载时订阅图像采集事件 | Subscribe to image captured event on load
        /// </summary>
        private void OnLoaded(object sender, RoutedEventArgs e)
        {
            try
            {
                _eventAggregator = ContainerLocator.Current?.Resolve<IEventAggregator>();
                if (_eventAggregator != null)
                {
                    _imageSubscriptionToken = _eventAggregator.GetEvent<ImageCapturedEvent>()
                        .Subscribe(OnImageCaptured, ThreadOption.BackgroundThread);
                }
            }
            catch
            {
                // 事件聚合器不可用时静默降级 | Silent degradation when event aggregator unavailable
            }
        }

        /// <summary>
        /// 卸载时取消订阅 | Unsubscribe on unload
        /// </summary>
        private void OnUnloaded(object sender, RoutedEventArgs e)
        {
            if (_eventAggregator != null && _imageSubscriptionToken != null)
            {
                _eventAggregator.GetEvent<ImageCapturedEvent>().Unsubscribe(_imageSubscriptionToken);
                _imageSubscriptionToken = null;
            }
        }

        /// <summary>
        /// 图像采集回调：将 ushort[] 转为 byte[] 后传给直方图控件 | Image captured callback
        /// </summary>
        private void OnImageCaptured(ImageCapturedEventArgs args)
        {
            if (args?.ImageData == null || args.Width == 0 || args.Height == 0)
                return;

            try
            {
                // 将 ushort[] 转换为 little-endian byte[] | Convert ushort[] to little-endian byte[]
                var rawBytes = new byte[args.ImageData.Length * 2];
                Buffer.BlockCopy(args.ImageData, 0, rawBytes, 0, rawBytes.Length);

                // 调用直方图控件更新（控件内部支持从非 UI 线程调用）| Update histogram control (supports non-UI thread calls)
                HistogramControl?.UpdateImage(rawBytes, (int)args.Width, (int)args.Height, 16);
            }
            catch
            {
                // 异常不影响主流程 | Exception does not affect main flow
            }
        }
    }
}