Display_D_HP/TeamAAS-VM/DxfModule/InteractionController.cs

using CSScripting;
using OxyPlot.Utilities;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using WpfShapes = System.Windows.Shapes;
using WpfPoint = System.Windows.Point;
using netDxf.Entities;

namespace TeamAAS_VP.DxfModule
{
    public class InteractionController
    {
        private readonly Canvas _canvas;
        private readonly HashSet<UIElement> _selectedElements = new HashSet<UIElement>();
        private WpfPoint _selectionStartPoint;
        private WpfShapes.Rectangle _selectionRectangle;
        private bool _isSelecting = false;

        public event EventHandler<SelectionChangedEventArgs> SelectionChanged;

        public InteractionController(Canvas canvas)
        {
            _canvas = canvas;
            AttachEvents();
        }

        private void AttachEvents()
        {
            _canvas.MouseLeftButtonDown += Canvas_MouseLeftButtonDown;
            _canvas.MouseLeftButtonUp += Canvas_MouseLeftButtonUp;
            _canvas.MouseMove += Canvas_MouseMove;
            _canvas.MouseRightButtonDown += Canvas_MouseRightButtonDown;
        }

        private void Canvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            _selectionStartPoint = e.GetPosition(_canvas);
            _isSelecting = true;

            // Check if clicking on an element
            var hitElement = GetElementAtPoint(_selectionStartPoint);

            if (hitElement != null)
            {
                // Single selection
                if (!Keyboard.IsKeyDown(Key.LeftCtrl) && !Keyboard.IsKeyDown(Key.RightCtrl))
                {
                    ClearSelection();
                }

                ToggleSelection(hitElement);
            }
            else
            {
                // Start box selection
                if (!Keyboard.IsKeyDown(Key.LeftCtrl) && !Keyboard.IsKeyDown(Key.RightCtrl))
                {
                    ClearSelection();
                }

                _selectionRectangle = new WpfShapes.Rectangle
                {
                    Stroke = Brushes.Blue,
                    StrokeThickness = 1,
                    StrokeDashArray = new DoubleCollection { 4, 2 },
                    Fill = new SolidColorBrush(Color.FromArgb(30, 0, 0, 255))
                };
                _canvas.Children.Add(_selectionRectangle);
            }
        }

        private void Canvas_MouseMove(object sender, MouseEventArgs e)
        {
            if (_isSelecting && _selectionRectangle != null)
            {
                var currentPoint = e.GetPosition(_canvas);

                var x = Math.Min(_selectionStartPoint.X, currentPoint.X);
                var y = Math.Min(_selectionStartPoint.Y, currentPoint.Y);
                var width = Math.Abs(_selectionStartPoint.X - currentPoint.X);
                var height = Math.Abs(_selectionStartPoint.Y - currentPoint.Y);

                Canvas.SetLeft(_selectionRectangle, x);
                Canvas.SetTop(_selectionRectangle, y);
                _selectionRectangle.Width = width;
                _selectionRectangle.Height = height;
            }
        }

        private void Canvas_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            if (_isSelecting && _selectionRectangle != null)
            {
                var endPoint = e.GetPosition(_canvas);
                var rect = new Rect(_selectionStartPoint, endPoint);

                // Select elements within the rectangle
                foreach (UIElement element in _canvas.Children)
                {
                    if (element == _selectionRectangle)
                        continue;

                    if (IsElementIntersecting(element, rect))
                    {
                        AddToSelection(element);
                    }
                }

                _canvas.Children.Remove(_selectionRectangle);
                _selectionRectangle = null;
            }

            _isSelecting = false;
        }

        private void Canvas_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
        {
            // Clear selection on right-click
            ClearSelection();
        }

        private UIElement GetElementAtPoint(WpfPoint point)
        {
            HitTestResult result = VisualTreeHelper.HitTest(_canvas, point);

            if (result != null && result.VisualHit is UIElement element)
            {
                // Make sure it's not the canvas itself
                if (element != _canvas && element.GetType() != typeof(WpfShapes.Rectangle))
                {
                    return element;
                }
            }

            return null;
        }

        private bool IsElementIntersecting(UIElement element, Rect selectionRect)
        {
            try
            {
                var elementBounds = GetElementBounds(element);
                return selectionRect.IntersectsWith(elementBounds);
            }
            catch
            {
                return false;
            }
        }

        private Rect GetElementBounds(UIElement element)
        {
            if (element is WpfShapes.Line line)
            {
                var x1 = line.X1;
                var y1 = line.Y1;
                var x2 = line.X2;
                var y2 = line.Y2;

                return new Rect(
                    new WpfPoint(Math.Min(x1, x2), Math.Min(y1, y2)),
                    new WpfPoint(Math.Max(x1, x2), Math.Max(y1, y2))
                );
            }
            else if (element is WpfShapes.Ellipse ellipse)
            {
                var left = Canvas.GetLeft(ellipse);
                var top = Canvas.GetTop(ellipse);
                return new Rect(left, top, ellipse.Width, ellipse.Height);
            }
            else if (element is WpfShapes.Shape shape)
            {
                return shape.RenderedGeometry.Bounds;
            }
            else if (element is FrameworkElement fe)
            {
                var left = Canvas.GetLeft(fe);
                var top = Canvas.GetTop(fe);
                return new Rect(left, top, fe.ActualWidth, fe.ActualHeight);
            }

            return Rect.Empty;
        }

        private void ToggleSelection(UIElement element)
        {
            if (_selectedElements.Contains(element))
            {
                RemoveFromSelection(element);
            }
            else
            {
                AddToSelection(element);
            }
        }

        private void AddToSelection(UIElement element)
        {
            if (element is FrameworkElement fe && fe.Tag is EntityObject)
            {
                _selectedElements.Add(element);
                GraphicsRenderer.HighlightElement(element, true);
                OnSelectionChanged();
            }
        }

        private void RemoveFromSelection(UIElement element)
        {
            if (_selectedElements.Contains(element))
            {
                _selectedElements.Remove(element);
                GraphicsRenderer.HighlightElement(element, false);
                OnSelectionChanged();
            }
        }

        public void ClearSelection()
        {
            foreach (var element in _selectedElements.ToList())
            {
                GraphicsRenderer.HighlightElement(element, false);
            }
            _selectedElements.Clear();
            OnSelectionChanged();
        }

        public List<EntityObject> GetSelectedEntities()
        {
            return _selectedElements
                .OfType<FrameworkElement>()
                .Where(e => e.Tag is EntityObject)
                .Select(e => (EntityObject)e.Tag)
                .ToList();
        }

        public int SelectedCount => _selectedElements.Count;

        private void OnSelectionChanged()
        {
            SelectionChanged?.Invoke(this, new SelectionChangedEventArgs(GetSelectedEntities()));
        }

        public void Detach()
        {
            _canvas.MouseLeftButtonDown -= Canvas_MouseLeftButtonDown;
            _canvas.MouseLeftButtonUp -= Canvas_MouseLeftButtonUp;
            _canvas.MouseMove -= Canvas_MouseMove;
            _canvas.MouseRightButtonDown -= Canvas_MouseRightButtonDown;
        }
    }

    public class SelectionChangedEventArgs : EventArgs
    {
        public List<EntityObject> SelectedEntities { get; }

        public SelectionChangedEventArgs(List<EntityObject> selectedEntities)
        {
            SelectedEntities = selectedEntities;
        }
    }
}