// ============================================================================
// Copyright © 2026 Hexagon Technology Center GmbH. All Rights Reserved.
// 文件名: PointToLineProcessor.cs
// 描述: 点到直线距离测量算子
// 功能:
//   - 用户定义一条直线（两个端点）和一个测量点
//   - 计算测量点到直线的垂直距离
//   - 支持像素尺寸标定输出物理距离
//   - 在图像上绘制直线、测量点、垂足和距离标注
// 算法: 点到直线距离公式
// 作者: 李伟 wei.lw.li@hexagon.com
// ============================================================================

using Emgu.CV;
using Emgu.CV.CvEnum;
using Emgu.CV.Structure;
using XP.ImageProcessing.Core;
using Serilog;
using System.Drawing;

namespace XP.ImageProcessing.Processors;

public class PointToLineProcessor : ImageProcessorBase
{
    private static readonly ILogger _logger = Log.ForContext<PointToLineProcessor>();

    public PointToLineProcessor()
    {
        Name = LocalizationHelper.GetString("PointToLineProcessor_Name");
        Description = LocalizationHelper.GetString("PointToLineProcessor_Description");
    }

    protected override void InitializeParameters()
    {
        // 直线两端点 + 测量点（由交互控件注入）
        Parameters.Add("L1X", new ProcessorParameter("L1X", "L1X", typeof(int), 100, null, null, "") { IsVisible = false });
        Parameters.Add("L1Y", new ProcessorParameter("L1Y", "L1Y", typeof(int), 200, null, null, "") { IsVisible = false });
        Parameters.Add("L2X", new ProcessorParameter("L2X", "L2X", typeof(int), 400, null, null, "") { IsVisible = false });
        Parameters.Add("L2Y", new ProcessorParameter("L2Y", "L2Y", typeof(int), 200, null, null, "") { IsVisible = false });
        Parameters.Add("PX", new ProcessorParameter("PX", "PX", typeof(int), 250, null, null, "") { IsVisible = false });
        Parameters.Add("PY", new ProcessorParameter("PY", "PY", typeof(int), 100, null, null, "") { IsVisible = false });

        Parameters.Add("PixelSize", new ProcessorParameter(
            "PixelSize",
            LocalizationHelper.GetString("PointToLineProcessor_PixelSize"),
            typeof(double), 1.0, null, null,
            LocalizationHelper.GetString("PointToLineProcessor_PixelSize_Desc")));

        Parameters.Add("Unit", new ProcessorParameter(
            "Unit",
            LocalizationHelper.GetString("PointToLineProcessor_Unit"),
            typeof(string), "px", null, null,
            LocalizationHelper.GetString("PointToLineProcessor_Unit_Desc"),
            new string[] { "px", "mm", "μm", "cm" }));

        Parameters.Add("Thickness", new ProcessorParameter(
            "Thickness",
            LocalizationHelper.GetString("PointToLineProcessor_Thickness"),
            typeof(int), 2, 1, 10,
            LocalizationHelper.GetString("PointToLineProcessor_Thickness_Desc")));
    }

    public override Image<Gray, byte> Process(Image<Gray, byte> inputImage)
    {
        int l1x = GetParameter<int>("L1X"), l1y = GetParameter<int>("L1Y");
        int l2x = GetParameter<int>("L2X"), l2y = GetParameter<int>("L2Y");
        int px = GetParameter<int>("PX"), py = GetParameter<int>("PY");
        double pixelSize = GetParameter<double>("PixelSize");
        string unit = GetParameter<string>("Unit");
        int thickness = GetParameter<int>("Thickness");

        OutputData.Clear();

        // 点到直线距离公式: |AB × AP| / |AB|
        double abx = l2x - l1x, aby = l2y - l1y;
        double abLen = Math.Sqrt(abx * abx + aby * aby);

        double pixelDistance = 0;
        int footX = px, footY = py;

        if (abLen > 0.001)
        {
            // 叉积求距离
            double cross = Math.Abs(abx * (l1y - py) - aby * (l1x - px));
            pixelDistance = cross / abLen;

            // 垂足: 投影参数 t = AP·AB / |AB|²
            double apx = px - l1x, apy = py - l1y;
            double t = (apx * abx + apy * aby) / (abLen * abLen);
            footX = (int)(l1x + t * abx);
            footY = (int)(l1y + t * aby);
            OutputData["ProjectionT"] = t;
        }

        double actualDistance = pixelDistance * pixelSize;

        string distanceText = unit == "px"
            ? $"{pixelDistance:F2} px"
            : $"{actualDistance:F4} {unit} ({pixelDistance:F2} px)";

        OutputData["PointToLineResult"] = true;
        OutputData["Line1"] = new Point(l1x, l1y);
        OutputData["Line2"] = new Point(l2x, l2y);
        OutputData["MeasurePoint"] = new Point(px, py);
        OutputData["FootPoint"] = new Point(footX, footY);
        OutputData["PixelDistance"] = pixelDistance;
        OutputData["ActualDistance"] = actualDistance;
        OutputData["Unit"] = unit;
        OutputData["Thickness"] = thickness;
        OutputData["DistanceText"] = distanceText;

        _logger.Information("PointToLine: Distance={Dist}, Foot=({FX},{FY})", distanceText, footX, footY);

        return inputImage.Clone();
    }
}