Snake

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;

namespace Snake
{  
    class Snake
    {
        static void Main(string[] args)
        {
            byte right = 0;
            byte left = 1;
            byte down = 2;
            byte up = 3;
            int lastFoodTime = 0;
            int foodDisappearTime = 8000;
            int negativePoints = 0;

            Position[] directions = new Position[]
            {
                new Position(0, 1), // right 
                new Position(0, -1), // left
                new Position(1, 0), // down
                new Position(-1, 0) // top
            };
            double sleepTime = 100;
            int direction = right;
            Random randomNumbersGenerator = new Random();
            Console.BufferHeight = Console.WindowHeight;
            
            lastFoodTime = Environment.TickCount;

            List<Position> obstacles = new List<Position>() 
            { 
                new Position(12, 12),
                new Position(14, 20),
                new Position(7, 7)
            };
            foreach (Position obstacle in obstacles)
            {
                Console.ForegroundColor = ConsoleColor.Cyan;
                Console.SetCursorPosition(obstacle.col, obstacle.row);
                Console.Write("=");
            }
            
            Queue<Position> snakeElements = new Queue<Position>();
            for (int i = 0; i <= 5; i++)
            {
                snakeElements.Enqueue(new Position(0, i));
            }

            Position food;
            do
            {
                food = new Position(randomNumbersGenerator.Next(0, Console.WindowHeight),
                                    randomNumbersGenerator.Next(0, Console.WindowWidth));
            } while (snakeElements.Contains(food) || obstacles.Contains(food));
            Console.SetCursorPosition(food.col, food.row);
            Console.ForegroundColor = ConsoleColor.Yellow;
            Console.Write("@");

            foreach (Position position in snakeElements)
            {
                Console.SetCursorPosition(position.col, position.row);
                Console.ForegroundColor = ConsoleColor.DarkGray;
                Console.Write("*");
            }
            
            while (true)
            {
                negativePoints++;

                if (Console.KeyAvailable)
                {
                    ConsoleKeyInfo userInput = Console.ReadKey();
                    if (userInput.Key == ConsoleKey.LeftArrow)
                    {
                        if (direction != right) direction = left;
                    }
                    if (userInput.Key == ConsoleKey.RightArrow)
                    {
                        if (direction != left) direction = right;
                    }
                    if (userInput.Key == ConsoleKey.UpArrow)
                    {
                        if (direction != down) direction = up;
                    }
                    if (userInput.Key == ConsoleKey.DownArrow)
                    {
                        if (direction != up) direction = down;
                    }
                }

                Position snakeHead = snakeElements.Last();
                Position nextDirection = directions[direction];
                Position snakeNewHead = new Position(snakeHead.row + nextDirection.row,
                                                     snakeHead.col + nextDirection.col);

                if (snakeNewHead.col < 0) snakeNewHead.col = Console.WindowWidth - 1;
                if (snakeNewHead.row < 0) snakeNewHead.row = Console.WindowHeight - 1;
                if (snakeNewHead.row >= Console.WindowHeight) snakeNewHead.row = 0;
                if (snakeNewHead.col >= Console.WindowWidth) snakeNewHead.col = 0;

                if (snakeElements.Contains(snakeNewHead) || obstacles.Contains(snakeNewHead))
                {
                    Console.SetCursorPosition(0, 0);
                    Console.ForegroundColor = ConsoleColor.Red;
                    Console.WriteLine("Game over!");
                    int userPoints = (snakeElements.Count - 6)  * 100 - negativePoints;
                    // if (userPoints < 0) userPoints = 0;
                    userPoints = Math.Max(userPoints, 0);
                    Console.WriteLine("Your points are: {0}", userPoints);
                    return;
                }

                Console.SetCursorPosition(snakeHead.col, snakeHead.row);
                Console.ForegroundColor = ConsoleColor.DarkGray;
                Console.Write("*");

                snakeElements.Enqueue(snakeNewHead);
                Console.SetCursorPosition(snakeNewHead.col, snakeNewHead.row);
                Console.ForegroundColor = ConsoleColor.Gray;
                if (direction == right) Console.Write(">");
                if (direction == left) Console.Write("<");
                if (direction == up) Console.Write("^");
                if (direction == down) Console.Write("v");

                if (snakeNewHead.col == food.col && snakeNewHead.row == food.row)
                {
                    // feeding the snake
                    do
                    {
                        food = new Position(randomNumbersGenerator.Next(0, Console.WindowHeight),
                                            randomNumbersGenerator.Next(0, Console.WindowWidth));
                    } while (snakeElements.Contains(food) || obstacles.Contains(food));
                    lastFoodTime = Environment.TickCount;
                    Console.SetCursorPosition(food.col, food.row);
                    Console.ForegroundColor = ConsoleColor.Yellow;
                    Console.Write("@");
                    sleepTime--;

                    Position obstacle = new Position();
                    do
                    {
                        obstacle = new Position(randomNumbersGenerator.Next(0, Console.WindowHeight),
                                                randomNumbersGenerator.Next(0, Console.WindowWidth));
                    } while (snakeElements.Contains(obstacle) ||
                             obstacles.Contains(obstacle) ||
                             (food.row != obstacle.row && food.col != obstacle.col));
                    obstacles.Add(obstacle);
                    Console.SetCursorPosition(obstacle.col, obstacle.row);
                    Console.ForegroundColor = ConsoleColor.Cyan;
                    Console.Write("=");
                }
                else
                {
                    // moving
                    Position last = snakeElements.Dequeue();
                    Console.SetCursorPosition(last.col, last.row);
                    Console.Write(" ");
                }

                if (Environment.TickCount - lastFoodTime >= foodDisappearTime)
                {
                    negativePoints = negativePoints + 50;
                    Console.SetCursorPosition(food.col, food.row);
                    Console.Write(" ");

                    do
                    {
                        food = new Position(randomNumbersGenerator.Next(0, Console.WindowHeight),
                                            randomNumbersGenerator.Next(0, Console.WindowWidth));
                    } while (snakeElements.Contains(food) || obstacles.Contains(food));
                    lastFoodTime = Environment.TickCount;
                }
                Console.SetCursorPosition(food.col, food.row);
                Console.ForegroundColor = ConsoleColor.Yellow;
                Console.Write("@");

                // Console.Clear();
                /*
                foreach (Position position in snakeElements)
                {
                    Console.SetCursorPosition(position.col, position.row);
                    Console.Write("*");
                }
               
                Console.SetCursorPosition(food.col, food.row);
                Console.Write("@");
                */
                sleepTime -= 0.01;

                Thread.Sleep((int)sleepTime);
            }
        }
    }
}