@interface AI : NSObject {

   char ttt[9];

   int firstMove;

   int rotation;

    

   int play;

}



- (int) userPlay:(int) input;

- (int) analiseGame;



- (void) visualizeBoard;



- (int) rightMove;



- (int) patternMatchWin;

- (int) patternMatchBlock;

- (int) patternMatchBlock2Moves;



- (int) firstEmptySpace;



- (void) reconvertMatrix;

- (int) convertValueToTrueMatrix:(int) aValue;



- (void) rotate90;



- (int) play;



@end

//

//  AI.m

//  TTT

//

//  Created by KhAoTiK TaChYoN on 12/24/05.

//  Copyright 2005 __MyCompanyName__. All rights reserved.

//



#import "AI.h"





@implementation AI



- (id) init

{

   self = [super init];

    

   firstMove = 1;

   rotation = 0;

    

   return self;

}



- (int) userPlay:(int) input

{

   if (ttt[input] != '\0') return -2; // Error... that square is already taken

    

   ttt[input] = 'X';

    

   if ([self analiseGame] != 2)

   {

      [self visualizeBoard];

      return [self analiseGame];

   }

    

   play = [self rightMove];

   ttt[play] = 'O';

    

   [self visualizeBoard];

    

   return [self analiseGame];

}



- (void) visualizeBoard

{

   int i;

   char vis[9];

    

   for (i = 0; i < 9; i++) {

      if (ttt[i] == '\0') vis[i] = ' ';

      else vis[i] = ttt[i];

   }

    

   NSLog(@"%c %c %c \n", vis[0], vis[1], vis[2]);

   NSLog(@"%c %c %c \n", vis[3], vis[4], vis[5]);

   NSLog(@"%c %c %c \n", vis[6], vis[7], vis[8]);

}



- (int) analiseGame

{

   // 1 = AI wins

   // -1 = User wins

   // 0 = Draw

   // 2 = In play

    

   if (ttt[0] == 'O' && ttt[1] == 'O' && ttt[2] == 'O') return 1;

   if (ttt[0] == 'X' && ttt[1] == 'X' && ttt[2] == 'X') return -1;

   if (ttt[3] == 'O' && ttt[4] == 'O' && ttt[5] == 'O') return 1;

   if (ttt[3] == 'X' && ttt[4] == 'X' && ttt[5] == 'X') return -1;

   if (ttt[6] == 'O' && ttt[7] == 'O' && ttt[8] == 'O') return 1;

   if (ttt[6] == 'X' && ttt[7] == 'X' && ttt[8] == 'X') return -1;

   if (ttt[0] == 'O' && ttt[3] == 'O' && ttt[6] == 'O') return 1;

   if (ttt[0] == 'X' && ttt[3] == 'X' && ttt[6] == 'X') return -1;

   if (ttt[1] == 'O' && ttt[4] == 'O' && ttt[7] == 'O') return 1;

   if (ttt[1] == 'X' && ttt[4] == 'X' && ttt[7] == 'X') return -1;

   if (ttt[2] == 'O' && ttt[5] == 'O' && ttt[8] == 'O') return 1;

   if (ttt[2] == 'X' && ttt[5] == 'X' && ttt[8] == 'X') return -1;

   if (ttt[0] == 'O' && ttt[4] == 'O' && ttt[8] == 'O') return 1;

   if (ttt[0] == 'X' && ttt[4] == 'X' && ttt[8] == 'X') return -1;

   if (ttt[2] == 'O' && ttt[4] == 'O' && ttt[6] == 'O') return 1;

   if (ttt[2] == 'X' && ttt[4] == 'X' && ttt[6] == 'X') return -1;

    

   if ([self firstEmptySpace] < 0) return 0;

    

   return 2;

}



- (int) rightMove

{

   int i, res;

    

   if (firstMove == 1)

   {

      /*

       1st move:

       - center if user hasn't chosen the center

       - corner if user chose the center

      */

      

      firstMove = 0;

      

      if (ttt[4] == '\0') return 4;

      else return 0;

   }

    

   for (i = 0; i < 4; i++)

   {

      res = [self patternMatchWin];

      

      if (res >= 0) {

         res = [self convertValueToTrueMatrix: res];

         [self reconvertMatrix];

         return res;

      }

      

      [self rotate90];

   }

    

   for (i = 0; i < 4; i++)

   {

      res = [self patternMatchBlock];

      

      if (res >= 0) {

         res = [self convertValueToTrueMatrix: res];

         [self reconvertMatrix];

         return res;

      }

      

      [self rotate90];

   }

    

   res = [self patternMatchBlock2Moves];

      

   if (res >= 0) {

      res = [self convertValueToTrueMatrix: res];

      [self reconvertMatrix];

      return res;

   }

    

   return [self firstEmptySpace];

    

   // if < 0, game is over...

}



- (int) patternMatchWin

{

   if (ttt[0] == '\0' && ttt[1] == 'O' && ttt[2] == 'O') return 0;

   if (ttt[0] == '\0' && ttt[3] == 'O' && ttt[6] == 'O') return 0;

   if (ttt[0] == '\0' && ttt[4] == 'O' && ttt[8] == 'O') return 0;

   if (ttt[1] == '\0' && ttt[0] == 'O' && ttt[2] == 'O') return 1;

   if (ttt[1] == '\0' && ttt[4] == 'O' && ttt[7] == 'O') return 1;

    

   return -1;

}

    

- (int) patternMatchBlock

{

   if (ttt[0] == '\0' && ttt[1] == 'X' && ttt[2] == 'X') return 0;

   if (ttt[0] == '\0' && ttt[3] == 'X' && ttt[6] == 'X') return 0;

   if (ttt[0] == '\0' && ttt[4] == 'X' && ttt[8] == 'X') return 0;

   if (ttt[1] == '\0' && ttt[0] == 'X' && ttt[2] == 'X') return 1;

   if (ttt[1] == '\0' && ttt[4] == 'X' && ttt[7] == 'X') return 1;

    

   return -1;

}

    

- (int) patternMatchBlock2Moves

{

   int i;

    

   for (i = 0; i < 4; i++)

   {

      if (ttt[0] == '\0' && ttt[1] == '\0' && ttt[2] == 'X' &&

         ttt[3] == '\0' && ttt[4] == 'X' &&  ttt[5] == '\0' &&

         ttt[6] == 'O' &&  ttt[7] == '\0' && ttt[8] == '\0') return 0;

      

      [self rotate90];

   }

    

   for (i = 0; i < 4; i++)

   {

      if (ttt[0] == '\0' && ttt[1] == '\0' && ttt[2] == 'X' &&

         ttt[3] == '\0' && ttt[4] == 'O' &&  ttt[5] == '\0' &&

         ttt[6] == 'X' &&  ttt[7] == '\0' && ttt[8] == '\0') return 1;

      

      [self rotate90];

   }

    

   for (i = 0; i < 4; i++)

   {

      if (ttt[0] == '\0' && ttt[1] == 'X' &&  ttt[2] == '\0' &&

         ttt[3] == 'X' &&  ttt[4] == 'O' &&

         ttt[6] == '\0') return 0;

      

      [self rotate90];

   }

    

   for (i = 0; i < 4; i++)

   {

      if (ttt[0] == '\0' && ttt[1] == 'X' &&  ttt[2] == '\0' &&

         ttt[3] == '\0' &&  ttt[4] == 'O' &&

         ttt[6] == 'X') return 0;

      

      [self rotate90];

   }

    

   for (i = 0; i < 4; i++)

   {

      if (ttt[0] == '\0' && ttt[1] == '\0' && ttt[2] == 'X' &&

         ttt[3] == 'X' &&  ttt[4] == 'O' &&

         ttt[6] == '\0') return 0;

      

      [self rotate90];

   }

    

   return -1;

}



- (int) firstEmptySpace

{

   int i;

    

   for (i = 0; i < 9; i++)

   {

      if (ttt[i] == '\0') return i;

   }

    

   return -1;

}



- (void) reconvertMatrix

{

   while (rotation > 0)

      [self rotate90];

}



- (int) convertValueToTrueMatrix:(int) aValue

{

   if (rotation == 0 || aValue == 4) return aValue;

    

   if (rotation == 1) {

      switch (aValue)

      {

         case 0: return 2;

         case 1: return 5;

         case 2: return 8;

         case 3: return 1;

         case 5: return 7;

         case 6: return 0;

         case 7: return 3;

         case 8: return 6;

      }

   }

          

   if (rotation == 2) {

      switch (aValue)

      {

         case 0: return 8;

         case 1: return 7;

         case 2: return 6;

         case 3: return 5;

         case 5: return 3;

         case 6: return 2;

         case 7: return 1;

         case 8: return 0;

      }

   }

    

   if (rotation == 3) {

      switch (aValue)

      {

         case 0: return 6;

         case 1: return 3;

         case 2: return 0;

         case 3: return 7;

         case 5: return 1;

         case 6: return 8;

         case 7: return 5;

         case 8: return 2;

      }

   }

    

   // Cannot reach this.

   return 111111;

}

      



- (void) rotate90

{

   int holder;

    

   holder = ttt[6];

   ttt[6] = ttt[0];

   ttt[0] = ttt[2];

   ttt[2] = ttt[8];

   ttt[8] = holder;

    

   holder = ttt[3];

   ttt[3] = ttt[1];

   ttt[1] = ttt[5];

   ttt[5] = ttt[7];

   ttt[7] = holder;

    

   rotation = (rotation + 1) % 4;

}



- (int) play

{

   return play;

}