LEA2/CheckersSpielBot/BoardRenderer.cs

using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Shapes;

namespace CheckersSpielBot
{
    public class BoardRenderer
    {
        // Frozen brushes — allocated once
        private static readonly SolidColorBrush BrushLightSquare = MakeBrush(0xEE, 0xEE, 0xEE);
        private static readonly SolidColorBrush BrushDarkSquare = MakeBrush(0x66, 0x66, 0x66);
        private static readonly SolidColorBrush BrushSelected = MakeBrush(0xFF, 0xD7, 0x00);
        private static readonly SolidColorBrush BrushValidMove = MakeBrush(0x4C, 0xAF, 0x50);
        private static readonly SolidColorBrush BrushMandatory = MakeBrush(0xFF, 0x60, 0x00);
        private static readonly SolidColorBrush BrushRedPiece = MakeBrush(0xB4, 0x1E, 0x1E);
        private static readonly SolidColorBrush BrushBluePiece = MakeBrush(0x1E, 0x1E, 0xB4);
        private static readonly SolidColorBrush BrushKingStar = new SolidColorBrush(Colors.Gold);

        private static SolidColorBrush MakeBrush(byte r, byte g, byte b)
        {
            var br = new SolidColorBrush(Color.FromRgb(r, g, b));
            br.Freeze();
            return br;
        }

        private readonly MainWindow _window;
        private readonly GameService _game;

        public BoardRenderer(MainWindow window, GameService game)
        {
            _window = window;
            _game = game;
        }

        public void RenderBoard(int selectedRow, int selectedCol,
                                bool hasPieceSelected, bool isChainJumpActive)
        {
            for (int row = 0; row < 8; row++)
                for (int col = 0; col < 8; col++)
                    RenderCell(row, col, selectedRow, selectedCol,
                               hasPieceSelected, isChainJumpActive);

            UpdatePieceCounts();
        }

        private void RenderCell(int row, int col,
                                int selectedRow, int selectedCol,
                                bool hasPieceSelected, bool isChainJumpActive)
        {
            Button btn = GetCellButton(row, col);
            if (btn == null) return;

            btn.Background = ResolveCellBackground(row, col, selectedRow, selectedCol,
                                                   hasPieceSelected, isChainJumpActive);
            btn.Content = BuildPieceVisual(_game.Board[row, col]);
        }

        private SolidColorBrush ResolveCellBackground(int row, int col,
                                                      int selectedRow, int selectedCol,
                                                      bool hasPieceSelected,
                                                      bool isChainJumpActive)
        {
            if (hasPieceSelected && selectedRow == row && selectedCol == col)
                return BrushSelected;

            if (hasPieceSelected && !isChainJumpActive && IsValidMoveTarget(row, col, selectedRow, selectedCol))
                return BrushValidMove;

            if (!hasPieceSelected && _game.MandatoryCapturePieces.Contains((row, col)))
                return BrushMandatory;

            return BoardHelper.IsPlayableSquare(row, col) ? BrushDarkSquare : BrushLightSquare;
        }

        private bool IsValidMoveTarget(int row, int col, int selectedRow, int selectedCol)
        {
            return _game.GetLegalMoves(selectedRow, selectedCol, capturesOnly: false)
                        .Exists(m => m.DestinationRow == row && m.DestinationCol == col);
        }

        private static UIElement? BuildPieceVisual(int piece)
        {
            if (piece == 0) return null;

            bool isRed = BoardHelper.IsRedPiece(piece);
            bool isKing = BoardHelper.IsKing(piece);

            var circle = new Ellipse
            {
                Width = 42,
                Height = 42,
                Fill = isRed ? BrushRedPiece : BrushBluePiece,
                HorizontalAlignment = HorizontalAlignment.Center,
                VerticalAlignment = VerticalAlignment.Center
            };

            var grid = new Grid();
            grid.Children.Add(circle);

            if (isKing)
            {
                grid.Children.Add(new TextBlock
                {
                    Text = "★",
                    FontSize = 16,
                    Foreground = BrushKingStar,
                    HorizontalAlignment = HorizontalAlignment.Center,
                    VerticalAlignment = VerticalAlignment.Center
                });
            }

            return grid;
        }

        private void UpdatePieceCounts()
        {
            var (red, blue) = _game.GetPieceCounts();
            _window.RedScoreText.Text = $"Red:  {red}";
            _window.BlueScoreText.Text = $"Blue: {blue}";
        }

        private Button GetCellButton(int row, int col) =>
            (Button)_window.FindName($"Cell_{row}_{col}");
    }
}