using ProjectGrid.Models;
using ProjectGrid.TicTacToc;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;

namespace ProjectGrid.AI
{
  public class TicTacTocBrain
  {
    private TicTacTocBoard _board;
    private int _player;

    private List<int> _prio;

    public TicTacTocBrain(TicTacTocBoard board, int player)
    {
      _board = board;
      _player = player;

      var rand = new Random();
      _prio = (new List<int> { 0, 1, 2, 3, 4, 5, 6, 7, 8 }).OrderBy(i => rand.Next()).ToList();
    }

    public int Turn()
    {
      if (_board.Field[4] == (int)Player.EMPTY)
      {
        //_board.SetFieldValue(_player, 5);
        return 4;
      }

      int blocking = -1;
      for (int x = 0; x < TicTacTocBoard._winning.GetLength(0); x++)
      {
        var _1 = _board.Field[TicTacTocBoard._winning[x, 0]];
        var _2 = _board.Field[TicTacTocBoard._winning[x, 1]];
        var _3 = _board.Field[TicTacTocBoard._winning[x, 2]];

        // any field set?
        if (_1 + _2 + _3 == 0)
          continue;

        var result = MatchWinning(_1, _2, _3);
        if (result.Item1 >= 0)
          return TicTacTocBoard._winning[x, result.Item1];

        if (result.Item2 >= 0)
          blocking = TicTacTocBoard._winning[x, result.Item2];
      }

      if (blocking >= 0)
        return blocking;

      foreach (var i in _prio)
        if (_board.Field[i] == 0)
          return i;

      Debug.Fail("Brain found no valid move!");
      return -1;
    }

    private (int win, int block) MatchWinning(int _1, int _2, int _3)
    {
      (int win, int block) result = (-1, -1);
      if (_1 == _2 && _1 != 0 && _3 == 0)
      {
        if (_1 == _player)
          result.win = 2;
        else
          result.block = 2;
      }
      else if (_1 == _3 && _1 != 0 && _2 == 0)
      {
        if (_1 == _player)
          result.win = 1;
        else
          result.block = 1;
      }
      else if (_2 == _3 && _2 != 0 && _1 == 0)
      {
        if (_1 == _player)
          result.win = 0;
        else
          result.block = 0;
      }

      return result;
    }
  }
}