#include <allegro.h>

//Adapted from http://www.cppgameprogramming.com/cgi/nav.cgi?page=tictactoe

BITMAP *imgPlayerOne;
BITMAP *imgPlayerTwo;

const signed short int PLAYER_ONE = -1, PLAYER_TWO = 1, EMPTY = 0;
const signed short int PIECE_WIDTH = 200, PIECE_HEIGHT = 150;

signed short int board[3][3];
unsigned short int currentRow = 0, currentColumn = 0, numMoves = 0;
signed short int currentPlayer = PLAYER_ONE;
bool gameActive = false;
              
int x = 0, y = 0, lastX = 0, lastY = 0;

void clearSelect ();
void drawBoard ();
void drawPiece (int player);
void drawSelect ();
bool hasWon (int player);
void gameEnd (int winner);
void move ();
void reset ();

void switchPlayer ();
void updateBoard ();

void clearSelect ()
{
	rect(screen, lastX+1, lastY+1, lastX + (PIECE_WIDTH - 1), lastY + (PIECE_HEIGHT - 1), makecol(0, 0, 0));
}

void drawBoard ()
{ 

    acquire_screen();
    
    rectfill(screen, 0, 0, (3 * PIECE_WIDTH), (3 * PIECE_HEIGHT), makecol(0, 0, 0));
    
    for (int row = 0; row < 3; row++)
    {
	    
	    for (int col = 0; col < 3; col++)
	    {
		    rect(screen, (row * PIECE_WIDTH), (col * PIECE_HEIGHT), ((row + 1) * PIECE_WIDTH), ((col + 1) * PIECE_HEIGHT), makecol(255, 255, 255));
	    }
	    
    }

    drawSelect();
        
    release_screen();
    
}    

void drawPiece (int player)
{
   
	if (player == PLAYER_ONE)
	{	
		draw_sprite(screen, imgPlayerOne, x, y);	
	}
	else
	{		
		draw_sprite(screen, imgPlayerTwo, x, y);
	}
	
}

void drawSelect ()
{	
	rect(screen, x+1, y+1, x + (PIECE_WIDTH - 1), y + (PIECE_HEIGHT - 1), makecol(255, 255, 0));	
}	

bool hasWon (int player)
{
	
	if (numMoves < 3)
	{
		return false;
	}
	//Check both digs
	if (board[1][1] == player && ((board[0][0] == player && board[2][2] == player) || (board[0][2] == player && board[2][0] == player)))
	{
		return true;
	}
	
	for (int col = 0; col < 3; col++)
	{
		
		if (board[0][col] == player && board[1][col] == player && board[2][col] == player)
		{
			return true;
		}
		
	}
	
	for (int row = 0; row < 3; row++)
	{
		
		if (board[row][0] == player && board[row][1] == player && board[row][2] == player)
		{
			return true;
		}
		
	}
	
	return false;
	
}

void gameEnd (int winner)
{
        
	if (winner == PLAYER_ONE)
	{		
		textout_ex(screen, font, "Player One Wins",  300, 240, makecol(255, 0, 0), makecol(0, 0, 0));
	}
	else if (winner == PLAYER_TWO)
	{
		textout_ex(screen, font, "Player Two Wins",  300, 240, makecol(255, 0, 0), makecol(0, 0, 0));  
	}
	else
	{
		textout_ex(screen, font, "Draw", 300, 240, makecol(255, 0, 0), makecol(0, 0, 0));
	}
	
	switchPlayer();
	
	gameActive = false;

}

void move ()
{
    
    clear_keybuf();    
    
    if (!gameActive)
    {
	    
	    if (key[KEY_ENTER])
	    {		    		    
		    reset();		    	    
	    }
	    
    }
    else
    {
	    
	    lastX = x;
    	lastY = y;
    
	    if (key[KEY_UP] && currentRow > 0)
	    {
	    
	        y -= 150;
	        currentRow--;
	        
	        updateBoard();
	        
	    }
	    else if (key[KEY_DOWN] && currentRow < 2)
	    {
		    
		    y += 150;
		    currentRow++;
		    
		    updateBoard();
		    
	    }
	    else if (key[KEY_RIGHT] && currentColumn < 2)
	    {
		    
		    x += 200;
		    currentColumn++;
		    
		    updateBoard();
		    
	    }
	    else if (key[KEY_LEFT] && currentColumn > 0)
	    {
		    
		    x -= 200;
		    currentColumn--;
		    
		    updateBoard();
		    
	    }
	    else if (key[KEY_ENTER] && board[currentRow][currentColumn] == EMPTY)
	    {
		    
		    acquire_screen();
		    drawPiece(currentPlayer);		    
		    	
			board[currentRow][currentColumn] = currentPlayer;
			numMoves++;
			
			if (hasWon(currentPlayer))
			{
				gameEnd(currentPlayer);
			}
			else if (numMoves >= 9)
			{
				gameEnd(EMPTY);
			}
			else
			{
				switchPlayer();
			}
			
			release_screen();
	
	    }
	    
    }
    
    rest(100);
    
}    

void reset ()
{
	
	for (int row = 0; row < 3; row++)
	{
		
		for (int col = 0; col < 3; col++)
		{
			board[row][col] = EMPTY;
		}
		
	}
	
	drawBoard();
	numMoves = 0;	
	gameActive = true;
	
}

void switchPlayer ()
{
	
	if (currentPlayer == PLAYER_ONE)
	{
		currentPlayer = PLAYER_TWO;
	}
	else
	{
		currentPlayer = PLAYER_ONE;
	}
	
}

void updateBoard ()
{ 
	
	acquire_screen();

    clearSelect();    
    drawSelect();
    
    release_screen();
    
}

int main ()
{
 
    allegro_init();
    install_keyboard();
    set_color_depth(16);
    set_gfx_mode(GFX_AUTODETECT_WINDOWED, (3 * PIECE_WIDTH), (3 * PIECE_HEIGHT), 0, 0);
    
    imgPlayerOne = load_bitmap("x.bmp", NULL);    
    imgPlayerTwo = load_bitmap("o.bmp", NULL);
    
    if (!(imgPlayerOne && imgPlayerTwo))
    {
	    alert("Could not load images \"x.bmp\" and \"o.bmp\"", "These should be placed in the same folder as the executable", "This programme will now terminate", "Ok", NULL, 'o', 0);
    }
    else
    {	    

	    reset();
	    
	    while(!key[KEY_ESC])
	    {
	        move();        
	    }
	    
    } 
    
    destroy_bitmap(imgPlayerOne);
    destroy_bitmap(imgPlayerTwo);
    
    return 0;
    
}   

END_OF_MAIN();