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

namespace TestPiktiv
{
    public class TicTacToe
    {
        private const int WinLength = 3;
        private int height = 15;
        private int width = 15;
        private char[,] buf;
        private bool isRunning;
        private char[,] board;
        private char[,] matchState;
        private (List<int> p1, List<int> p2) score = (new List<int>(), new List<int>());

        private ConsoleKey[] xKeys =
        [
            ConsoleKey.D1,
            ConsoleKey.D2,
            ConsoleKey.D3,
            ConsoleKey.D4,
            ConsoleKey.D5,
            ConsoleKey.D6,
            ConsoleKey.D7,
            ConsoleKey.D8,
            ConsoleKey.D9
        ];

        private int[,] magicSquare = new int[3, 3]
        {
            {4, 9, 2},
            {3, 5, 7},
            {8, 1, 6},
        };
        private bool player;
        private string winText;
        private bool shouldEndGame;

        public static void Main(string[] args)
        {
            TicTacToe game = new();
            game.Start();
        }

        public void Start()
        {
            Console.Clear();
            buf = new char[height, width];
            Console.CursorVisible = false;
            InitializeBoard();
            BuildBoard(matchState);
            isRunning = true;
            shouldEndGame = false;
            player = true;
            Tick();
            Console.CursorVisible = true;
        }

        private void InitializeBoard()
        {
            matchState = new char[3, 3];
            var index = 1;
            for (int i = 0; i < 3; i++)
            {
                for (int j = 0; j < 3; j++)
                {
                    char inc = index++.ToString()[0];
                    matchState[i, j] = inc;
                }
            }
            BuildBoard(matchState);
        }

        private void ClearBuffer()
        {
            for (int i = 0; i < height; i++)
            {
                for (int j = 0; j < height; j++)
                {
                    buf[i, j] = ' ';
                }
            }
        }

        private void BuildBoard(char[,] state)
        {
            board = new char[7, 7]
            {
                {'╔','═','╦','═','╦','═','╗'},
                {'║',state[0,0],'║',state[0,1],'║',state[0,2],'║'},
                {'╠','═','╬','═','╬','═','╣'},
                {'║',state[1,0],'║',state[1,1],'║',state[1,2],'║'},
                {'╠','═','╬','═','╬','═','╣'},
                {'║',state[2,0],'║',state[2,1],'║',state[2,2],'║'},
                {'╚','═','╩','═','╩','═','╝'},
            };
        }

        private void SolveBoard(int index)
        {
            int h = index / 3;
            int w = index % 3;
            if (matchState[h, w] != 'X' && matchState[h, w] != 'O')
            {
                matchState[h, w] = player ? 'X' : 'O';
                CheckWiningCondition_CheckNeighbors((h, w));
                player = !player;
            }
        }

        // a fun/hacky way of solving this problem using a magic square where the sum of a
        // speific set of numbers on all lines and columns is always 15
        private void CheckWiningCondition_MagicSquare((int h, int w) index)
        {
            if (player)
            {
                score.p1.Add(magicSquare[index.h, index.w]);
                if (CheckMagicSquare(score.p1))
                {
                    HandleWin(player);
                    return;
                }
                return;
            }

            score.p2.Add(magicSquare[index.h, index.w]);
            if (CheckMagicSquare(score.p2))
            {
                HandleWin(!player);
            }
        }

        private void CheckWiningCondition_CheckNeighbors((int h, int w) index)
        {
            if (CheckNeighbors(index))
            {
                HandleWin(player);
            }
        }

        // solved by scanning the direct neighbors, optimized solution that works with any board size
        private bool CheckNeighbors((int h, int w) index)
        {
            char symbol = matchState[index.h, index.w];
            var rows = matchState.GetLength(0);
            var columns = matchState.GetLength(1);

            (int dh, int dw)[] axes = [(0, 1), (1, 0), (-1, 1), (1, 1)];

            foreach (var (dh, dw) in axes)
            {
                int found = 1;

                for (int k = 1; ; k++)
                {
                    int r = index.h + dh * k;
                    int l = index.w + dw * k;
                    if (r < 0 || r >= rows || l < 0 || l >= columns)
                    {
                        break;
                    }
                    if (matchState[r, l] != symbol)
                    {
                        break;
                    }
                    found++;
                }

                for (int k = 1; ; k++)
                {
                    int r = index.h - dh * k;
                    int l = index.w - dw * k;
                    if (r < 0 || r >= rows || l < 0 || l >= columns)
                    {
                        break;
                    }
                    if (matchState[r, l] != symbol)
                    {
                        break;
                    }
                    found++;
                }

                if (found >= WinLength)
                {
                    return true;
                }
            }

            return false;

        }

        private bool CheckMagicSquare(List<int> claimed)
        {
            if (claimed.Count < 3)
            {
                return false;
            }

            for (int i = 0; i < claimed.Count; i++)
            {
                for (int j = i + 1; j < claimed.Count; j++)
                {
                    for (int k = j + 1; k < claimed.Count; k++)
                    {
                        if (claimed[i] + claimed[j] + claimed[k] == 15)
                        {
                            return true;
                        }
                    }
                }
            }

            return false;

        }

        private void HandleWin(bool player)
        {
            winText = player ? "Player 1 won!" : "Player 2 won!";
            shouldEndGame = true;
        }

        private void Tick()
        {
            while (isRunning)
            {
                CheckStatus(HandleInput());
                Render();
                Thread.Sleep(40);
                if (shouldEndGame)
                {
                    EndGame();
                }
            }

        }

        private void CheckStatus(ConsoleKey consoleKey)
        {
            if (xKeys.Contains(consoleKey))
            {
                SolveBoard(Array.IndexOf(xKeys, consoleKey));
            }

            for (int i = 0; i < matchState.GetLength(0); i++)
            {
                for (int j = 0; j < matchState.GetLength(1); j++)
                {
                    if (matchState[i, j] != 'X' && matchState[i, j] != 'O')
                    {
                        return;
                    }
                }
            }

            shouldEndGame = true;
        }

        private ConsoleKey HandleInput()
        {
            if (Console.KeyAvailable)
            {
                var key = Console.ReadKey(true).Key;
                if (key == ConsoleKey.Escape)
                {
                    shouldEndGame = true;
                }
                return key;
            }
            return ConsoleKey.None;
        }

        private void Render()
        {
            ClearBuffer();
            BuildBoard(matchState);
            AddBoardToBuffer();
            Present();
        }

        private void AddBoardToBuffer()
        {
            for (int i = 4; i < height - 4; i++)
            {
                for (int j = 4; j < width - 4; j++)
                {
                    buf[i, j] = board[i - 4, j - 4];
                }
            }
        }

        private void Present()
        {
            var sb = new StringBuilder(height * (width + 1));
            for (int i = 0; i < height; i++)
            {
                for (int j = 0; j < width; j++)
                {
                    sb.Append(buf[i, j]);
                }
                if (i < height + 1)
                {
                    sb.Append('\n');
                }
            }
            Console.SetCursorPosition(0, 0);
            Console.Write(sb.ToString());
        }

        private void EndGame()
        {
            Console.SetCursorPosition(0, height + 1);
            Console.WriteLine(winText);
            Console.WriteLine("Game Over. Press any key to restart!");
            Console.WriteLine("..or press Esc to exit!");
            var key = Console.ReadKey(true).Key;
            if (key == ConsoleKey.Escape)
            {
                isRunning = false;
                return;
            }
            Start();
        }

    }
}