using OpenCvSharp;
using System.Drawing.Imaging;

namespace anjianjingling.Vision
{
    /// <summary>
    /// 找图：OpenCV 模板匹配（TM_CCOEFF_NORMED），支持相似度阈值。
    /// </summary>
    public sealed class ImageFinder : IDisposable
    {
        private readonly Dictionary<string, Mat> _templateCache = new(StringComparer.OrdinalIgnoreCase);

        private static Mat BitmapToMat(Bitmap bmp)
        {
            using var ms = new MemoryStream();
            bmp.Save(ms, ImageFormat.Png);
            return Cv2.ImDecode(ms.ToArray(), ImreadModes.Color);
        }

        private Mat LoadTemplate(string path)
        {
            if (_templateCache.TryGetValue(path, out var cached)) return cached;
            if (!File.Exists(path))
                throw new FileNotFoundException($"模板图片不存在：{path}");
            var mat = Cv2.ImRead(path, ImreadModes.Color);
            if (mat.Empty())
                throw new InvalidDataException($"模板图片无法读取：{path}");
            _templateCache[path] = mat;
            return mat;
        }

        /// <summary>
        /// 在 haystack 位图中查找模板。
        /// </summary>
        /// <param name="haystack">被查找的画面（通常是区域截图）</param>
        /// <param name="templatePath">模板图路径</param>
        /// <param name="threshold">相似度阈值 0~1</param>
        /// <param name="offsetX">结果坐标要加上的屏幕偏移 X</param>
        /// <param name="offsetY">结果坐标要加上的屏幕偏移 Y</param>
        /// <returns>匹配中心屏幕坐标与相似度；未达阈值返回 (-1,-1,score)</returns>
        public (int X, int Y, double Score) Find(Bitmap haystack, string templatePath,
            double threshold, int offsetX = 0, int offsetY = 0)
        {
            using var hay = BitmapToMat(haystack);
            using var tpl = LoadTemplate(templatePath);

            if (tpl.Width > hay.Width || tpl.Height > hay.Height)
                throw new ArgumentException($"模板图({tpl.Width}x{tpl.Height})大于查找区域({hay.Width}x{hay.Height})");

            using var result = new Mat();
            Cv2.MatchTemplate(hay, tpl, result, TemplateMatchModes.CCoeffNormed);
            Cv2.MinMaxLoc(result, out _, out double maxVal, out _, out OpenCvSharp.Point maxLoc);

            if (maxVal >= threshold)
            {
                int cx = offsetX + maxLoc.X + tpl.Width / 2;
                int cy = offsetY + maxLoc.Y + tpl.Height / 2;
                return (cx, cy, maxVal);
            }
            return (-1, -1, maxVal);
        }

        /// <summary>清除模板缓存（模板文件更新后调用）。</summary>
        public void ClearCache()
        {
            foreach (var m in _templateCache.Values) m.Dispose();
            _templateCache.Clear();
        }

        public void Dispose()
        {
            ClearCache();
        }
    }
}