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

namespace Snake
{
    class Program
    {
        static Point apple = null;
        static bool AppleE = false;

        enum Directions
        {
            Up,
            Right,
            Down,
            Left
        }
        class Snake
        {
            public List<Point> points;
            public Point head;
            public Directions direction;

            public Snake(Point start)
            {
                points = new List<Point> {start};
                head = start;
                direction = Directions.Down;
            }

            public void Move(Point point)
            {

                points.Add(point);
                head = point;
                Console.SetCursorPosition(point.x, point.y);
                Console.Write("#");

                if (point == apple)
                {
                    AppleE = false;
                }
                else
                {
                    Console.SetCursorPosition(points[0].x, points[0].y);

                    Console.Write(" ");
                    points.RemoveAt(0);
                }
            }
        }
        class Point : IEquatable<Point>
        {
            public int x, y;

            public Point()
            {
                y = size / 2;
                x = size;
            }

            public Point(int x, int y)
            {
                this.x = x;
                this.y = y;
            }

            public bool Equals(Point other)
            {
                if (other == null)
                {
                    return false;
                }
                return x == other.x && y == other.y;
            }

            public override bool Equals(object obj)
            {
                if (obj == null)
                {
                    return false;
                }

                Point other = obj as Point;
                return Equals(other);
            }

            static public bool operator ==(Point left, Point right)
            {
                if (left is null || right is null)
                {
                    return false;
                }
                return ((left.x == right.x) && (left.y == right.y));
            }
            static public bool operator !=(Point left, Point right)
            {
                if (left is null || right is null)
                {
                    return false;
                }
                return ((left.x != right.x) || (left.y != right.y));
            }

        }
        static int size = 20;
        static void Map()
        {
            for (int i = 0; i <= size + 1; i++)
            {
                Console.SetCursorPosition(i * 2, 0); //Верхняя горизонталь
                Console.Write("X");
                Console.SetCursorPosition(0, i); //Левая горизонталь
                Console.Write("X");
                Console.SetCursorPosition(i * 2, size + 1); //Нижняя горизонталь
                Console.Write("X");
                Console.SetCursorPosition((size + 1) * 2, i); //Правая горизонталь
                Console.Write("X");
            }
        }
        static void GameOver()
        {
            Console.Clear();
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine("Game Over!");
        }
        static bool Cont(Snake player)
        {
            ConsoleKeyInfo button;

            Point HeadPos = new Point(player.head.x, player.head.y);
            button = Console.ReadKey(true);
            switch (button.Key)
            {
                case ConsoleKey.W:
                    if(player.direction == Directions.Down)
                    {
                        return true;
                    }
                    if (HeadPos.y == 1)
                    {
                        GameOver();
                        return false;
                    }
                    else
                    {
                        HeadPos.y--;
                        player.direction = Directions.Up;
                    }
                    break;
                case ConsoleKey.A:
                    if(player.direction == Directions.Right)
                    {
                        return true;
                    }
                    if (HeadPos.x == 1)
                    {
                        GameOver();
                        return false;
                    }
                    else
                    {
                        HeadPos.x -= 2;
                        player.direction = Directions.Left;
                    }
                    break;
                case ConsoleKey.S:
                    if(player.direction == Directions.Up)
                    {
                        return true;
                    }
                    if (HeadPos.y == size)
                    {
                        GameOver();
                        return false;
                    }
                    else
                    {
                        HeadPos.y++;
                        player.direction = Directions.Down;
                    }
                    break;
                case ConsoleKey.D:
                    if (player.direction == Directions.Left)
                    {
                        return true;
                    }
                    if (HeadPos.x == size * 2 + 1)
                    {
                        GameOver();
                        return false;
                    }
                    else
                    {
                        HeadPos.x += 2;
                        player.direction = Directions.Right;
                    }
                    break;
                default:
                    return true;
            }
            player.Move(HeadPos);

            return true;
        }
        static void Main(string[] args)
        {
            Console.CursorVisible = false;
            Map();

            Random r = new Random();
            Snake snake = new Snake(new Point(r.Next(1, size + 1) * 2 - 1, r.Next(1, size + 1)));
            Console.SetCursorPosition(snake.points[0].x, snake.points[0].y);
            Console.Write("#");




            while (Cont(snake))
            {
                if (!AppleE)
                {
                    do
                    {
                        apple = new Point(r.Next(1, size + 1) * 2 - 1, r.Next(1, size + 1));
                    } while (snake.points.Contains(apple));
                     Console.SetCursorPosition(apple.x, apple.y);
                    Console.Write("*");
                    AppleE = true;
                }
            }
        }

    }
}