using DrawFigureLibrary.Figures;
using System.Globalization;
using System.Windows;
using System.Windows.Media;

namespace DrawFigureLibrary
{
    public class TerrainPointSunPointHumanPointText : Figure
    {
        private const    double          ReferenceWidth    = 800.0 ;
        private const    double          ReferenceHeight   = 400.0 ;
        private const    double          SunCenterX        = 90    ;
        private const    double          SunCenterY        = 70    ;
        private const    double          SunRadius         = 28    ;
        private const    double          SunRayLength      = 26    ;
        private const    double          SunRayBase        = 24    ;
        private const    double          GreetingFontBase  = 28    ;
        private const    double          GreetingFontScale = 0.9   ;
        private const    double          GreetingTextX     = 330   ;
        private const    double          GreetingTextY     = 20    ;
        private const    double          FieldBaseY        = 400   ;
        private const    double          FieldCenterX      = 400   ;
        private const    double          FieldRadiusX      = 400   ;
        private const    double          FieldRadiusY      = 150   ;
        private const    double          PersonCenterX     = 400   ;
        private const    double          PersonScale       = 0.80  ;
        private const    double          HeadRadius        = 18    ;
        private const    double          BodyWidth         = 46    ;
        private const    double          BodyHeight        = 72    ;
        private const    double          ArmWidth          = 78    ;
        private const    double          ArmHeight         = 12    ;
        private const    double          LegWidth          = 12    ;
        private const    double          LegHeight         = 56    ;
        private const    double          LegGap            = 8     ;
        private readonly int             _sceneX                   ;
        private readonly int             _sceneY                   ;
        private          int             _humanDx                  ;
        private          int             _humanDy                  ;
        private readonly CircleFigure    _sunCore                  ;
        private readonly Triangle        _rayUp                    ;
        private readonly Triangle        _rayRight                 ;
        private readonly Triangle        _rayDown                  ;
        private readonly Triangle        _rayLeft                  ;
        private readonly CircleFigure    _head                     ;
        private readonly RectangleFigure _body                     ;
        private readonly RectangleFigure _leftArm                  ;
        private readonly RectangleFigure _rightArm                 ;
        private readonly RectangleFigure _leftLeg                  ;
        private readonly RectangleFigure _rightLeg                 ;

        public TerrainPointSunPointHumanPointText(string name, int x, int y, int sceneWidth, int sceneHeight)
            : base(name, x, y, sceneWidth, sceneHeight)
        {
            if (sceneWidth <= 0 || sceneHeight <= 0) throw new ArgumentException("sceneWidth/sceneHeight должны быть > 0");

            _sceneX = x;
            _sceneY = y;

            _sunCore  = new CircleFigure    ( name + "_sun",      0, 0, 1                                                       );
            _rayUp    = new Triangle        ( name + "_rayUp",                new Point(0, 0), new Point(0, 0), new Point(0, 0) );
            _rayRight = new Triangle        ( name + "_rayRight",             new Point(0, 0), new Point(0, 0), new Point(0, 0) );
            _rayDown  = new Triangle        ( name + "_rayDown",              new Point(0, 0), new Point(0, 0), new Point(0, 0) );
            _rayLeft  = new Triangle        ( name + "_rayLeft",              new Point(0, 0), new Point(0, 0), new Point(0, 0) );
            _head     = new CircleFigure    ( name + "_head",     0, 0, 1                                                       );
            _body     = new RectangleFigure ( name + "_body",     0, 0, 1, 1                                                    );
            _leftArm  = new RectangleFigure ( name + "_armL",     0, 0, 1, 1                                                    );
            _rightArm = new RectangleFigure ( name + "_armR",     0, 0, 1, 1                                                    );
            _leftLeg  = new RectangleFigure ( name + "_legL",     0, 0, 1, 1                                                    );
            _rightLeg = new RectangleFigure ( name + "_legR",     0, 0, 1, 1                                                    );
        }

        public override void Draw(DrawingContext dc)
        {
            double scaleX = w / ReferenceWidth;
            double scaleY = h / ReferenceHeight;

            UpdateSunPrimitives(scaleX, scaleY);
            _sunCore  .Draw(dc);
            _rayUp    .Draw(dc);
            _rayRight .Draw(dc);
            _rayDown  .Draw(dc);
            _rayLeft  .Draw(dc);

            DrawGreeting(dc, scaleX, scaleY);

            DrawFieldArc(dc, scaleX, scaleY);

            double groundYRef =
                GetTopEllipseYAtX(
                    PersonCenterX,
                    FieldCenterX,
                    FieldBaseY,
                    FieldRadiusX,
                    FieldRadiusY
                );

            UpdatePersonPrimitives(PersonCenterX, groundYRef, scaleX, scaleY, _humanDx, _humanDy);

            _leftLeg  .Draw(dc);
            _rightLeg .Draw(dc);
            _body     .Draw(dc);
            _leftArm  .Draw(dc);
            _rightArm .Draw(dc);
            _head     .Draw(dc);

            DrawCap(
                dc,
                PersonCenterX                                + _humanDx,
                GetHeadCenterYRef(PersonCenterX, groundYRef) + _humanDy,
                HeadRadius                                   * PersonScale,
                scaleX,
                scaleY
            );
        }

        public override void MoveBy(int deltaX, int deltaY)
        {
            if (Init.DrawingImage == null) return;

            double scaleX = w / ReferenceWidth;
            double scaleY = h / ReferenceHeight;

            var bbox = GetPersonBoundingBox(scaleX, scaleY, _humanDx + deltaX, _humanDy + deltaY);

            double maxW = Init.DrawingImage.ActualWidth;
            double maxH = Init.DrawingImage.ActualHeight;

            if (bbox.Left >= 0 &&
                bbox.Top >= 0 &&
                bbox.Right <= maxW &&
                bbox.Bottom <= maxH)
            {
                _humanDx += deltaX;
                _humanDy += deltaY;
            }
        }

        private void UpdateSunPrimitives(double scaleX, double scaleY)
        {
            double cx = _sceneX + SunCenterX * scaleX;
            double cy = _sceneY + SunCenterY * scaleY;
            double rX = SunRadius * scaleX;
            double rY = SunRadius * scaleY;

            _sunCore.x = (int)Math.Round(cx - rX);
            _sunCore.y = (int)Math.Round(cy - rY);
            _sunCore.w = (int)Math.Round(2 * rX);
            _sunCore.h = (int)Math.Round(2 * rY);

            SetTrianglePoints(_rayUp,
                ToScenePoint( SunCenterX,                  SunCenterY - SunRadius - SunRayLength, scaleX, scaleY ),
                ToScenePoint( SunCenterX - SunRayBase / 2, SunCenterY - SunRadius,                scaleX, scaleY ),
                ToScenePoint( SunCenterX + SunRayBase / 2, SunCenterY - SunRadius,                scaleX, scaleY )
            );

            SetTrianglePoints(_rayRight,
                ToScenePoint( SunCenterX + SunRadius + SunRayLength, SunCenterY,                  scaleX, scaleY ),
                ToScenePoint( SunCenterX + SunRadius,                SunCenterY - SunRayBase / 2, scaleX, scaleY ),
                ToScenePoint( SunCenterX + SunRadius,                SunCenterY + SunRayBase / 2, scaleX, scaleY )
            );

            SetTrianglePoints(_rayDown,
                ToScenePoint( SunCenterX,                  SunCenterY + SunRadius + SunRayLength, scaleX, scaleY ),
                ToScenePoint( SunCenterX - SunRayBase / 2, SunCenterY + SunRadius,                scaleX, scaleY ),
                ToScenePoint( SunCenterX + SunRayBase / 2, SunCenterY + SunRadius,                scaleX, scaleY )
            );

            SetTrianglePoints(_rayLeft,
                ToScenePoint( SunCenterX - SunRadius - SunRayLength, SunCenterY,                  scaleX, scaleY ),
                ToScenePoint( SunCenterX - SunRadius,                SunCenterY - SunRayBase / 2, scaleX, scaleY ),
                ToScenePoint( SunCenterX - SunRadius,                SunCenterY + SunRayBase / 2, scaleX, scaleY )
            );
        }

        private void UpdatePersonPrimitives(double centerXRef, double groundYRef, double scaleX, double scaleY, int dx, int dy)
        {
            double k = PersonScale;

            double headRadius = HeadRadius * k;

            double bodyWidth = BodyWidth * k;
            double bodyHeight = BodyHeight * k;

            double armWidth = ArmWidth * k;
            double armHeight = ArmHeight * k;

            double legWidth = LegWidth * k;
            double legHeight = LegHeight * k;
            double legGap = LegGap * k;

            double gapFromGround = 4 / k;
            double feetY = groundYRef - gapFromGround;

            double legsTopY = feetY - legHeight;

            SetRect(_leftLeg,
                centerXRef - legGap / 2 - legWidth + dx,
                legsTopY + dy,
                legWidth,
                legHeight,
                scaleX, scaleY
            );

            SetRect(_rightLeg,
                centerXRef + legGap / 2 + dx,
                legsTopY + dy,
                legWidth,
                legHeight,
                scaleX, scaleY
            );

            double bodyX = centerXRef - bodyWidth / 2;
            double bodyY = legsTopY - bodyHeight;

            SetRect(_body,
                bodyX + dx,
                bodyY + dy,
                bodyWidth,
                bodyHeight,
                scaleX, scaleY
            );

            double armY = bodyY + bodyHeight * 0.30;

            SetRect(_leftArm,
                bodyX - armWidth + dx,
                armY + dy,
                armWidth,
                armHeight,
                scaleX, scaleY
            );

            SetRect(_rightArm,
                bodyX + bodyWidth + dx,
                armY + dy,
                armWidth,
                armHeight,
                scaleX, scaleY
            );

            double headCenterY = bodyY - headRadius * 1.05;

            SetCircle(_head,
                centerXRef + dx,
                headCenterY + dy,
                headRadius,
                scaleX, scaleY
            );
        }

        private void DrawGreeting(DrawingContext dc, double scaleX, double scaleY)
        {
            string text = GetGreetingByTime();

            double pixelsPerDip = 1.0;
            try
            {
                if (Application.Current?.MainWindow != null) pixelsPerDip = VisualTreeHelper.GetDpi(Application.Current.MainWindow).PixelsPerDip;
            }
            catch { }

            var formattedText = new FormattedText(
                text,
                CultureInfo.GetCultureInfo("ru-RU"),
                FlowDirection.LeftToRight,
                new Typeface("Segoe UI"),
                (GreetingFontBase * GreetingFontScale) * scaleY,
                Brushes.Black,
                pixelsPerDip
             );

            dc.DrawText(formattedText, ToScenePoint(GreetingTextX, GreetingTextY, scaleX, scaleY));
        }

        private void DrawFieldArc(DrawingContext dc, double scaleX, double scaleY)
        {
            DrawTopHalfEllipseArc(dc, FieldCenterX, FieldBaseY, FieldRadiusX, FieldRadiusY, scaleX, scaleY);
        }

        private void DrawCap(DrawingContext dc, double headCenterXRef, double headCenterYRef, double headRadiusRef, double scaleX, double scaleY)
        {
            double capBaseY = headCenterYRef - headRadiusRef;

            double capRadiusX = headRadiusRef * 1.10;
            double capRadiusY = headRadiusRef * 0.85;

            double leftX = headCenterXRef - capRadiusX;
            double rightX = headCenterXRef + capRadiusX;

            var geometry = new StreamGeometry();
            using (var ctx = geometry.Open())
            {
                ctx.BeginFigure(ToScenePoint(leftX, capBaseY, scaleX, scaleY), isFilled: false, isClosed: false);
                ctx.ArcTo(
                    ToScenePoint(rightX, capBaseY, scaleX, scaleY),
                    new Size(capRadiusX * scaleX, capRadiusY * scaleY),
                    rotationAngle: 0,
                    isLargeArc: false,
                    sweepDirection: SweepDirection.Clockwise,
                    isStroked: true,
                    isSmoothJoin: false
                );
            }

            dc.DrawGeometry(null, Init.pen, geometry);

            double brimLength = headRadiusRef * 3;
            double brimStartX = headCenterXRef - capRadiusX;

            dc.DrawLine(Init.pen,
                ToScenePoint(brimStartX, capBaseY, scaleX, scaleY),
                ToScenePoint(brimStartX + brimLength, capBaseY + headRadiusRef * 0.05, scaleX, scaleY)
            );
        }


        private Rect GetPersonBoundingBox(double scaleX, double scaleY, int dx, int dy)
        {
            double k = PersonScale;

            double headRadius = HeadRadius * k;
            double bodyWidth = BodyWidth * k;
            double bodyHeight = BodyHeight * k;
            double armWidth = ArmWidth * k;
            double legWidth = LegWidth * k;
            double legHeight = LegHeight * k;
            double legGap = LegGap * k;

            double groundYRef = GetTopEllipseYAtX(PersonCenterX, FieldCenterX, FieldBaseY, FieldRadiusX, FieldRadiusY);

            double gapFromGround = 4 / k;
            double feetY = groundYRef - gapFromGround;

            double legsTopY = feetY - legHeight;
            double bodyY = legsTopY - bodyHeight;

            double headCenterY = bodyY - headRadius * 1.05;
            double capTopY = (headCenterY - headRadius) - (headRadius * 0.85);

            double left = PersonCenterX - (bodyWidth / 2 + armWidth);
            double right = PersonCenterX + (bodyWidth / 2 + armWidth);
            double top = capTopY;
            double bottom = feetY;

            Point tl = ToScenePoint(left + dx, top + dy, scaleX, scaleY);
            Point br = ToScenePoint(right + dx, bottom + dy, scaleX, scaleY);

            return new Rect(tl, br);
        }

        private static double GetHeadCenterYRef(double centerXRef, double groundYRef)
        {
            double k = PersonScale;
            double headRadius = HeadRadius * k;
            double bodyHeight = BodyHeight * k;
            double legHeight = LegHeight * k;

            double gapFromGround = 4 / k;
            double feetY = groundYRef - gapFromGround;
            double legsTopY = feetY - legHeight;
            double bodyY = legsTopY - bodyHeight;

            return bodyY - headRadius * 1.05;
        }

        private void DrawTopHalfEllipseArc(DrawingContext dc, double centerX, double centerY, double radiusX, double radiusY, double scaleX, double scaleY)
        {
            Point start = ToScenePoint(centerX - radiusX, centerY, scaleX, scaleY);
            Point end = ToScenePoint(centerX + radiusX, centerY, scaleX, scaleY);

            var geometry = new StreamGeometry();
            using (var ctx = geometry.Open())
            {
                ctx.BeginFigure(start, isFilled: false, isClosed: false);
                ctx.ArcTo(
                    end,
                    new Size(radiusX * scaleX, radiusY * scaleY),
                    rotationAngle: 0,
                    isLargeArc: false,
                    sweepDirection: SweepDirection.Clockwise,
                    isStroked: true,
                    isSmoothJoin: false
                );
            }

            dc.DrawGeometry(null, Init.pen, geometry);
        }

        private static double GetTopEllipseYAtX(double x, double centerX, double centerY, double radiusX, double radiusY)
        {
            double dx = (x - centerX) / radiusX;
            double inside = 1.0 - dx * dx;
            if (inside < 0) inside = 0;
            return centerY - radiusY * Math.Sqrt(inside);
        }

        private Point ToScenePoint(double localX, double localY, double scaleX, double scaleY)
            => new Point(_sceneX + localX * scaleX, _sceneY + localY * scaleY);

        private void SetRect(RectangleFigure rect, double localX, double localY, double localW, double localH, double scaleX, double scaleY)
        {
            rect.x = (int)Math.Round(_sceneX + localX * scaleX);
            rect.y = (int)Math.Round(_sceneY + localY * scaleY);
            rect.w = (int)Math.Round(localW * scaleX);
            rect.h = (int)Math.Round(localH * scaleY);
        }

        private void SetCircle(CircleFigure circle, double centerXRef, double centerYRef, double radiusRef, double scaleX, double scaleY)
        {
            double cx = _sceneX + centerXRef * scaleX;
            double cy = _sceneY + centerYRef * scaleY;
            double rx = radiusRef * scaleX;
            double ry = radiusRef * scaleY;

            circle.x = (int)Math.Round(cx - rx);
            circle.y = (int)Math.Round(cy - ry);
            circle.w = (int)Math.Round(2 * rx);
            circle.h = (int)Math.Round(2 * ry);
        }

        private static void SetTrianglePoints(Triangle t, Point a, Point b, Point c)
        {
            t.Points[0] = a;
            t.Points[1] = b;
            t.Points[2] = c;
        }

        private static string GetGreetingByTime()
        {
            int hour = DateTime.Now.Hour;
            if (hour >= 5 && hour <= 11) return "Доброе утро!";
            if (hour >= 12 && hour <= 17) return "Добрый день!";
            return "Добрый вечер!";
        }

        public override bool MoveByChecked(int deltaX, int deltaY)
        {
            if (Init.DrawingImage == null) return false;

            double scaleX = w / ReferenceWidth;
            double scaleY = h / ReferenceHeight;

            var bbox = GetPersonBoundingBox(scaleX, scaleY, _humanDx + deltaX, _humanDy + deltaY);

            double maxW = Init.DrawingImage.ActualWidth;
            double maxH = Init.DrawingImage.ActualHeight;

            if (bbox.Left >= 0 &&
                bbox.Top >= 0 &&
                bbox.Right <= maxW &&
                bbox.Bottom <= maxH)
            {
                _humanDx += deltaX;
                _humanDy += deltaY;
                return true;
            }

            return false;
        }

        public override bool HitTest(Point p)
        {
            double scaleX = w / ReferenceWidth;
            double scaleY = h / ReferenceHeight;

            Rect bbox = GetPersonBoundingBox(scaleX, scaleY, _humanDx, _humanDy);

            return bbox.Contains(p);
        }
    }
}