using System;
using System.Runtime.InteropServices;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using Emgu.CV;
using Emgu.CV.CvEnum;

namespace XP.Common.Converters
{
    /// <summary>
    /// 图像数据转换工具类，基于 Emgu CV 实现
    /// </summary>
    public static class ImageConverter
    {
        /// <summary>
        /// 将 16 位无符号灰度数据转换为 RGB BitmapSource
        /// 使用 Emgu CV 的 Normalize 进行线性拉伸，CvtColor 转 BGR
        /// </summary>
        /// <param name="data">16 位灰度原始数据</param>
        /// <param name="width">图像宽度</param>
        /// <param name="height">图像高度</param>
        /// <returns>BGR24 格式的 BitmapSource</returns>
        public static BitmapSource ConvertGray16ToBitmapSource(ushort[] data, int width, int height)
        {
            if (data == null) throw new ArgumentNullException(nameof(data));
            if (width <= 0 || height <= 0) throw new ArgumentException("图像尺寸无效");

            // 从 ushort[] 按字节拷贝构建 16 位灰度 Mat
            using var mat16 = new Mat(height, width, DepthType.Cv16U, 1);
            int byteCount = data.Length * sizeof(ushort);
            unsafe
            {
                fixed (ushort* pData = data)
                {
                    Buffer.MemoryCopy(pData, mat16.DataPointer.ToPointer(), byteCount, byteCount);
                }
            }

            // 归一化到 0~255 并转为 8 位
            using var mat8 = new Mat();
            CvInvoke.Normalize(mat16, mat8, 0, 255, NormType.MinMax, DepthType.Cv8U);

            // 灰度转 BGR（立式 CT 显示需要 RGB 格式）
            using var matBgr = new Mat();
            CvInvoke.CvtColor(mat8, matBgr, ColorConversion.Gray2Bgr);

            // Mat 转 BitmapSource
            return MatToBitmapSource(matBgr);
        }

        /// <summary>
        /// 将 Emgu CV Mat 转换为 WPF BitmapSource
        /// </summary>
        private static BitmapSource MatToBitmapSource(Mat mat)
        {
            int width = mat.Width;
            int height = mat.Height;
            int channels = mat.NumberOfChannels;
            int stride = mat.Step;

            byte[] pixels = new byte[height * stride];
            Marshal.Copy(mat.DataPointer, pixels, 0, pixels.Length);

            var format = channels == 3 ? PixelFormats.Bgr24 : PixelFormats.Gray8;
            return BitmapSource.Create(width, height, 96, 96, format, null, pixels, stride);
        }
    }
}