namespace XP.ImageProcessing.Core.Alignment;

/// <summary>
/// 将示教图（模板坐标系）上的 ROI 点变换到运行图坐标。
/// 旋转中心与模板匹配一致：绕 <see cref="Pose2D.X"/>/<see cref="Pose2D.Y"/>（pattern 中心）。
/// </summary>
public static class RoiAlignment
{
    /// <summary>
    /// 刚体变换：示教图点 → 运行图点。
    /// <paramref name="reference"/>：示教图上的基准位姿；
    /// <paramref name="measured"/>：运行图匹配位姿。
    /// </summary>
    public static Point2D TransformPoint(Point2D point, Pose2D reference, Pose2D measured)
    {
        double dTheta = DegreesToRadians(measured.AngleDegrees - reference.AngleDegrees);
        double cos = Math.Cos(dTheta);
        double sin = Math.Sin(dTheta);
        double dx = point.X - reference.X;
        double dy = point.Y - reference.Y;
        return new Point2D(
            measured.X + cos * dx - sin * dy,
            measured.Y + sin * dx + cos * dy);
    }

    public static Point2D TransformPoint(double x, double y, Pose2D reference, Pose2D measured)
        => TransformPoint(new Point2D(x, y), reference, measured);

    /// <summary>变换多边形顶点（顺序不变）。</summary>
    public static Point2D[] TransformPolygon(IReadOnlyList<Point2D> templatePoints, Pose2D reference, Pose2D measured)
    {
        if (templatePoints == null || templatePoints.Count == 0)
            return Array.Empty<Point2D>();

        var result = new Point2D[templatePoints.Count];
        for (int i = 0; i < templatePoints.Count; i++)
            result[i] = TransformPoint(templatePoints[i], reference, measured);
        return result;
    }

    /// <summary>变换后四舍五入为整型顶点，供 BGA 等算子 PolyX/PolyY 注入。</summary>
    public static (int X, int Y)[] TransformPolygonToInt(
        IReadOnlyList<Point2D> templatePoints,
        Pose2D reference,
        Pose2D measured)
    {
        var transformed = TransformPolygon(templatePoints, reference, measured);
        var result = new (int X, int Y)[transformed.Length];
        for (int i = 0; i < transformed.Length; i++)
        {
            result[i] = (
                (int)Math.Round(transformed[i].X, MidpointRounding.AwayFromZero),
                (int)Math.Round(transformed[i].Y, MidpointRounding.AwayFromZero));
        }

        return result;
    }

    /// <summary>变换轴对齐矩形为四个顶点（左上、右上、右下、左下）。</summary>
    public static Point2D[] TransformRect(double x, double y, double width, double height, Pose2D reference, Pose2D measured)
    {
        var corners = new[]
        {
            new Point2D(x, y),
            new Point2D(x + width, y),
            new Point2D(x + width, y + height),
            new Point2D(x, y + height)
        };
        return TransformPolygon(corners, reference, measured);
    }

    /// <summary>
    /// 校验匹配结果四角质心是否与 Center 一致（用于确认库的中心/角度约定）。
    /// </summary>
    public static bool IsMatchCenterConsistentWithCorners(
        double centerX,
        double centerY,
        double ltX,
        double ltY,
        double rtX,
        double rtY,
        double rbX,
        double rbY,
        double lbX,
        double lbY,
        double tolerancePixels = 1.0)
    {
        double cx = (ltX + rtX + rbX + lbX) * 0.25;
        double cy = (ltY + rtY + rbY + lbY) * 0.25;
        double dx = cx - centerX;
        double dy = cy - centerY;
        return dx * dx + dy * dy <= tolerancePixels * tolerancePixels;
    }

    private static double DegreesToRadians(double degrees) => degrees * (Math.PI / 180.0);
}