feat: initial project structure with Snake.Core, CLI and Avalonia skeleton

Snake.Core/SnakeGame.cs

@@ -0,0 +1,60 @@
+namespace Snake.Core;
+
+public sealed class SnakeGame
+{
+    public SnakeGame(int width, int height, Random? random = null)
+    {
+        _random = random ?? Random.Shared;
+        Board = new Board(width, height);
+
+        var start = new Position(width / 2, height / 2);
+        Snake = new Snake(start, length: 3, Direction.Right);
+        Food = new Food(Board, Snake.Segments, _random);
+    }
+
+    private readonly Random _random;
+
+    public Board Board { get; }
+
+    public Snake Snake { get; }
+
+    public Food Food { get; }
+
+    public int Score { get; private set; }
+
+    public bool IsGameOver { get; private set; }
+
+    public void SetDirection(Direction direction) => Snake.SetDirection(direction);
+
+    public GameTickResult Tick()
+    {
+        if (IsGameOver)
+            return GameTickResult.GameOver;
+
+        var newHead = Snake.PeekNextHead();
+
+        if (!Board.IsWithinBounds(newHead) || Snake.Occupies(newHead))
+        {
+            IsGameOver = true;
+            return GameTickResult.GameOver;
+        }
+
+        var ateFood = newHead == Food.Position;
+        Snake.Move(grow: ateFood);
+
+        if (ateFood)
+        {
+            Score++;
+            if (Snake.Segments.Count >= Board.Width * Board.Height)
+            {
+                IsGameOver = true;
+                return GameTickResult.AteFood;
+            }
+
+            Food.Respawn(Snake.Segments);
+            return GameTickResult.AteFood;
+        }
+
+        return GameTickResult.Moved;
+    }
+}