What a mess... but now with some actual snake logic!

Self-collision is in
Food is in (currently will cause lag with very large snakes due to re-rolling rng if position occupied by snake segment)
Wall pass-through is in as well, right wall is a bit iffy because of the scroll bar and the auto-advance of the cursor on write

ConsoleSnake/Program.cs

@@ -1,4 +1,6 @@
-namespace ConsoleSnake
+using System.ComponentModel.Design;
+
+namespace ConsoleSnake
 {
     internal class Program
     {
@@ -10,24 +12,166 @@
             Right
         }
 
+        private struct PlayArea
+        {
+            public PlayArea(Int32 left, Int32 top, Int32 right, Int32 bottom)
+            {
+                LeftEdge = left;
+                TopEdge = top;
+                RightEdge = right;
+                BottomEdge = bottom;
+            }
+            public Int32 LeftEdge { get; set; }
+            public Int32 TopEdge { get; set; }
+            public Int32 RightEdge { get; set; }
+            public Int32 BottomEdge { get; set; }
+        }
+
+        private struct Position2D
+        {
+            public Position2D(Int32 x, Int32 y) { X = x; Y = y; }
+            public Int32 X { get; set; }
+            public Int32 Y { get; set; }
+        }
+
+        private static PlayArea _playArea;
         private static bool _running = true;
+        private static bool _growing = false;
         private static Direction _direction = Direction.Up;
+        private static List<Position2D> _snakeSegments = new List<Position2D>();
+        private static Position2D _food = new Position2D(-1,-1);
+        private static Random rng = new Random();
         static void Main(string[] args)
         {
-            Console.SetCursorPosition(Console.WindowWidth/2, Console.WindowHeight/2);
+            Console.ReadKey();
+            Console.WindowWidth -= Console.WindowWidth % 2;
+            Console.WindowHeight -= Console.WindowHeight % 2;
+            Console.SetBufferSize(Console.WindowWidth, Console.WindowHeight);
+
+            DrawPlayArea();
+            
+            //Console.WindowWidth -= 1;
+            Console.ReadKey(true);
+            Reset();
+
+
             while (_running)
             {
                 HandleInput();
-                ProcessMovement();
+                AllSnakeThings();
-                DrawSnake();
+                Thread.Sleep(50);
-                Thread.Sleep(100);
             }
         }
 
-        private static void DrawSnake()
+        private static void DrawPlayArea()
         {
+            Console.BackgroundColor = ConsoleColor.DarkGray;
+            for(Int32 top = 0; top < Console.WindowHeight; ++top)
+            {
+                Console.CursorTop = top;
+                Console.CursorLeft = 0;
+                if (top == 0 || top == Console.WindowHeight - 1)
+                    for (Int32 row = 0; row < Console.WindowWidth; ++row)
+                        Console.Write(' ');
+                else
+                {
+                    Console.Write(' ');
+                    Console.CursorLeft = Console.WindowWidth-1;
+                    Console.Write(' ');
+                }
+            }
+            /*for (Int32 top = _playArea.Top; top < _playArea.Height; ++top)
+            {
+
+            }
+            for (Int32 left = _playArea.Left; left < _playArea.Width; ++left)
+            {
+                Console.SetCursorPosition(left, top);
+                Console.Write(' ');
+            }*/
+            Console.BackgroundColor = ConsoleColor.Black;
+        }
+        private static void Reset()
+        {
+            _playArea = new PlayArea(1, 1, Console.WindowWidth - 2, Console.WindowHeight - 2);
+            _running = true;
+            _growing = false;
+            _direction = Direction.Up;
+            _snakeSegments.Clear();
+
+            // Set up anew
+            _snakeSegments.Add(new Position2D(Console.BufferWidth / 2, Console.BufferHeight / 2));
+            SpawnFood();
+            MoveCursor(_snakeSegments.Last());
+
+        }
+
+        private static void SpawnFood()
+        {
+            Position2D oldCursorPos = new Position2D(Console.CursorLeft, Console.CursorTop);
+            do
+            {
+                _food = new Position2D(rng.Next(3, Console.WindowWidth - 10), rng.Next(3, Console.WindowHeight - 3));
+            } while (_snakeSegments.Contains(_food));
+            MoveCursor(_food);
+            Console.ForegroundColor = ConsoleColor.Red;
+            Console.Write('@');
+            Console.ForegroundColor = ConsoleColor.Green;
+            MoveCursor(oldCursorPos);
+        }
+
+        private static void MoveCursor(Position2D pos) => MoveCursor(pos.X, pos.Y);
+        private static void MoveCursor(Int32 left, Int32 top)
+        {
+            Console.SetCursorPosition(left, top);
+            Console.CursorVisible = false;
+        }
+
+        private static void GrowSnake() => GrowSnake(Console.CursorLeft, Console.CursorTop);
+        private static void GrowSnake(Int32 x, Int32 y)
+        {
+            _snakeSegments.Add(new Position2D(x, y));
+        }
+
+        private static void DeleteAt(Position2D pos) => DeleteAt(pos.X, pos.Y);
+        private static void DeleteAt(Int32 x, Int32 y)
+        {
+            Int32 curX = Console.CursorLeft;
+            Int32 curY = Console.CursorTop;
+            MoveCursor(x, y);
+            Console.Write(' ');
+            MoveCursor(curX, curY);
+        }
+
+        private static bool Collision(Position2D pos1, Position2D pos2)
+        {
+            return (pos1.X == pos2.X && pos1.Y == pos2.Y);
+        }
+
+        private static void AllSnakeThings()
+        {
+            if (!_growing)
+            {
+                DeleteAt(_snakeSegments.First());
+                _snakeSegments.Remove(_snakeSegments.First());
+            }
+            else
+                _growing = false;
+            ProcessMovement();
+            if (_snakeSegments.Contains(new Position2D(Console.CursorLeft, Console.CursorTop)))
+            {
+                _running = false;
+                return;
+            }
+
+            GrowSnake();
             Console.Write('#');
             --Console.CursorLeft;
+            if(_food.X == Console.CursorLeft && _food.Y == Console.CursorTop)
+            {
+                _growing = true;
+                SpawnFood();
+            }
         }
 
         private static void ProcessMovement()
@@ -35,17 +179,29 @@
             switch (_direction)
             {
                 case Direction.Up:
+                    if (Console.CursorTop - 1 < _playArea.TopEdge)
+                        Console.CursorTop = _playArea.BottomEdge;
+                    else
                         --Console.CursorTop;
                     break;
                 case Direction.Down:
+                    if (Console.CursorTop + 1 > _playArea.BottomEdge)
+                        Console.CursorTop = _playArea.TopEdge;
+                    else
                         ++Console.CursorTop;
                     break;
-                case Direction.Right:
-                    ++Console.CursorLeft;
-                    break;
                 case Direction.Left:
+                    if (Console.CursorLeft - 1 < _playArea.LeftEdge)
+                        Console.CursorLeft = _playArea.RightEdge;
+                    else
                         --Console.CursorLeft;
                     break;
+                case Direction.Right:
+                    if (Console.CursorLeft + 1 > _playArea.RightEdge)
+                        Console.CursorLeft = _playArea.LeftEdge;
+                    else
+                        ++Console.CursorLeft;
+                    break;
             }
         }
 
@@ -57,23 +213,30 @@
                 {
                     case ConsoleKey.UpArrow:
                     case ConsoleKey.W:
+                        if(_direction != Direction.Down)
                             _direction = Direction.Up;
                         break;
                     case ConsoleKey.DownArrow:
                     case ConsoleKey.S:
+                        if (_direction != Direction.Up)
                             _direction = Direction.Down;
                         break;
                     case ConsoleKey.LeftArrow:
                     case ConsoleKey.A:
+                        if (_direction != Direction.Right)
                             _direction = Direction.Left;
                         break;
                     case ConsoleKey.RightArrow:
                     case ConsoleKey.D:
+                        if (_direction != Direction.Left)
                             _direction = Direction.Right;
                         break;
                     case ConsoleKey.Escape:
                         _running = false;
                         break;
+                    case ConsoleKey.G:
+                        _growing = !_growing;
+                        break;
                 }
             }
         }