using System;

using System.Collections.Generic;

using System.Linq;

using static System.Console;

​

namespace Example

{

    class Program

    {

        static (int X, int Y) PlayerLocation;

        static Tile[,] Map;

​

        static void Main()

        {

            bool InvalidInput = false;

            Home:

            Clear();

            WriteLine("Wumpus World...");

            WriteLine();

            WriteLine("Home:");

            WriteLine();

            WriteLine(

                "Rumors say that the Wumpus has a stash of gold " +

                "inside his cave, but few who enter ever return. " +

                "Will you seek the gold?");

            WriteLine();

            WriteLine("yes:  enter the cave of the Wumpus");

            WriteLine("quit: exit Wumpus World");

            WriteLine("info: view info");

            WriteLine();

            if (InvalidInput)

            {

                WriteLine("Invalid Input. Try again...");

            }

            Write(">");

            switch (ReadLine())

            {

                case "quit": Quit(); goto Home;

                case "info": Info(); goto Home;

                case "yes": GenerateCave(); Play(); goto Home;

                default: InvalidInput = true; goto Home;

            };

        }

​

        static void Info()

        {

            Clear();

            WriteLine("Wumpus World...");

            WriteLine();

            WriteLine("Rules:");

            WriteLine();

            WriteLine(

                "The Wumpus's cave is a 4x4 grid. It is dark, and you " +

                "can only see the reach of your hands. The Wumpus will " +

                "eat you if you disturb him, but you can smell him " +

                "when he is close. The Wumpus's cave is also full of pits " +

                "he uses to trap his prey. Be careful not to fall in one; " +

                "you can feel a breeze when a pit is near. If you find the " +

                "gold, you may exit the way you came.");

            WriteLine();

            WriteLine("Press Enter To Return...");

            ReadLine();

        }

​

        static void Quit()

        {

            bool InvalidInput = false;

            Quit:

            Clear();

            WriteLine("Wumpus World...");

            WriteLine();

            WriteLine("Quit:");

            WriteLine();

            WriteLine("Are you sure you want to quit?");

            WriteLine();

            WriteLine("yes: quit");

            WriteLine("no:  return");

            WriteLine();

            if (InvalidInput)

            {

                WriteLine("Invalid Input. Try again...");

            }

            Write(">");

            switch (ReadLine())

            {

                case "yes": Clear(); Environment.Exit(0); return;

                case "no": return;

                default: InvalidInput = true; goto Quit;

            };

        }

​

        static void Play()

        {

            static IEnumerable<Tile> AdjacentTiles()

            {

                int x = PlayerLocation.X;

                int y = PlayerLocation.Y;

                if (x > 0) yield return Map[x - 1, y];

                if (x < Map.GetLength(0) - 1) yield return Map[x + 1, y];

                if (y > 0) yield return Map[x, y - 1];

                if (y < Map.GetLength(1) - 1) yield return Map[x, y + 1];

            }

​

            static bool AdjacentToWumpus() => AdjacentTiles().Contains(Tile.Wumpus);

            static bool AdjacentToPit() => AdjacentTiles().Contains(Tile.Pit);

​

            bool InvalidInput = false;

            string move = null;

            Play:

            Clear();

            WriteLine("Wumpus World...");

            WriteLine();

            WriteLine("Play:");

            WriteLine();

            if (!(move is null))

            {

                WriteLine(move);

                WriteLine();

            }

            Write("You are inside the cave of the Wumpus.");

            if (AdjacentToWumpus())

            {

                Write(" You smell a foul odor from something nearby.");

            }

            if (AdjacentToPit())

            {

                Write(" You feel a breeze. Watch your step.");

            }

            WriteLine();

            WriteLine();

            WriteLine("up:    move up");

            WriteLine("down:  move down");

            WriteLine("left:  move left");

            WriteLine("right: move right");

            WriteLine("quit:  exit Wumpus World");

            WriteLine("info:  view info");

            WriteLine();

            if (InvalidInput)

            {

                WriteLine("Invalid Input. Try again...");

            }

            Write(">");

            Direction movement;

            switch (ReadLine())

            {

                case "quit": Quit(); goto Play;

                case "info": Info(); goto Play;

                case "up": movement = Direction.Up; break;

                case "down": movement = Direction.Down; break;

                case "left": movement = Direction.Left; break;

                case "right": movement = Direction.Right; break;

                default: InvalidInput = true; goto Play;

            };

            bool insideMap = movement switch

            {

                Direction.Up => PlayerLocation.Y < Map.GetLength(1) - 1,

                Direction.Down => PlayerLocation.Y > 0,

                Direction.Left => PlayerLocation.X > 0,

                Direction.Right => PlayerLocation.X < Map.GetLength(0) - 1,

                _ => throw new Exception(),

            };

            move = insideMap

                ? "You moved " + movement.ToString().ToLower() + "."

                : "You tried to move " + movement.ToString().ToLower() + " but you ran into a wall.";

            if (insideMap)

            {

                PlayerLocation = movement switch

                {

                    Direction.Up => (PlayerLocation.X, PlayerLocation.Y + 1),

                    Direction.Down => (PlayerLocation.X, PlayerLocation.Y - 1),

                    Direction.Left => (PlayerLocation.X - 1, PlayerLocation.Y),

                    Direction.Right => (PlayerLocation.X + 1, PlayerLocation.Y),

                    _ => throw new Exception(),

                };

                switch (Map[PlayerLocation.X, PlayerLocation.Y])

                {

                    case Tile.Gold: Clear(); WriteLine("You found the gold and left the cave the way you entered. You win."); ReadLine(); return;

                    case Tile.Wumpus: Clear(); WriteLine("You got eaten by the Wumpus. You lose."); ReadLine(); return;

                    case Tile.Pit: Clear(); WriteLine("You fell into one of the Wumpus's pits. You lose."); ReadLine(); return;

                }

            }

            goto Play;

        }

​

        static void GenerateCave()

        {

            const int width = 4;

            const int height = 4;

​

            Map = new Tile[width, height];

​

            // Get Random Locations

            Random random = new Random();

            (int X, int Y)[] randomCoordinates = random.UniqueInts(5, 1..(width * height)).Select(i => (i / width, i % width)).ToArray();

            var wumpusLocation = randomCoordinates[0];

            var goldLocation = randomCoordinates[1];

            var pitLocations = randomCoordinates[2..^0];

​

            // Place Randomized Locations On Map

            Map[wumpusLocation.X, wumpusLocation.Y] = Tile.Wumpus;

            Map[goldLocation.X, goldLocation.Y] = Tile.Gold;

            Array.ForEach(pitLocations, pit => Map[pit.X, pit.Y] = Tile.Pit);

​

            // Default Player Location

            PlayerLocation = default;

        }

    }

​

    #region Enums

​

    enum Direction

    {

        Up,

        Down,

        Left,

        Right,

    }

​

    enum Tile

    {

        Normal = 0,

        Wumpus,

        Gold,

        Pit,

    }

​

    #endregion

​

    #region Helpers

​

    public static class Helpers

    {

        internal class Node

        {

            internal int Value;

            internal Node Next;

        }

​

        public static IEnumerable<int> UniqueInts(this Random random, int count, Range range)

        {

            if (random is null)

                throw new ArgumentNullException(nameof(random));

            (int a, int b) = range.End.Value < range.Start.Value

                ? (range.End.Value, range.Start.Value)

                : (range.Start.Value, range.End.Value);

            if (count < 0)

                throw new ArgumentOutOfRangeException(nameof(count) + " < 0");

            if (b - a < count)

                throw new ArgumentOutOfRangeException(nameof(count) + " is larger than " + nameof(range));

​

            Node head = null;

            for (int i = 0; i < count; i++)

            {

                int roll = random.Next(a, b - i);

                Node node = head;

                Node previous = null;

                while (!(node is null))

                {

                    if (node.Value > roll)

                        break;

                    roll++;

                    previous = node;

                    node = node.Next;

                }

                yield return roll;

                if (previous is null)

                    head = new Node() { Value = roll, Next = head, };

                else

                    previous.Next = new Node() { Value = roll, Next = previous.Next };

            }

        }

    }

​

    #endregion

}

​