ai.cpp

#include "ai.h"

/* Possible Tile Values??
 ___ ___ ___ ___ ___ ___ ___ ___
 1| 99| -8|  8|  6|  6|  8| -8| 99|
 2| -8|-24| -4| -3| -3| -4|-24| -8|
 3|  8| -4|  7|  4|  4|  7| -4|  8|
 4|  6| -3|  4|  0|  0|  4| -3|  6|
 5|  6| -3|  4|  0|  0|  4| -3|  6|
 6|  8| -4|  7|  4|  4|  7| -4|  8|
 7| -8|-24| -4| -3| -3| -4|-24| -8|
 8| 99| -8|  8|  6|  6|  8| -8| 99|
 a   b   c   d   e   f   g   h*/

//EASY depth 1
//MEDIUM depth 3
//HARD depth 5
AI::~AI() {

}

int AI::getValue(GameEngine game, Tile player) {
	int playerValue = 0,
		oppValue = 0;
	for (int i = 0 ; i < 8 ; ++i) {
		for (int j = 0 ; j < 8 ; ++j) {
			if (game.getSpace(i,j) == player) {
				playerValue += values[i][j];
			}
			else if (game.getSpace(i,j) == game.opposite(player)) {
				oppValue += values[i][j];
			}
		}
	}
	return playerValue - oppValue;
}

Space AI::chooseMove(GameEngine game, int depth, Tile player) {
	vector<Space> moves = game.showPossibleMoves(player);
	Space bestMove;
	int bestval = -1000;
	for (int i = 0 ; i < moves.size() ; ++i) {
		game.makeMove(moves[i].getRow(), moves[i].getColumn(), player);
		int tmp = minimax(game, depth-1, player, player);
		if (tmp > bestval) {
			bestMove = moves[i];
			bestval = tmp;
		}
		game.undoMove();
	}
    return bestMove;            
}

int AI::minimax(GameEngine game, int depth, Tile player, Tile maxing) {
	if (game.gameOver() || depth == 0){
        return getValue(game, maxing);
    }

    vector<Space> moves = game.showPossibleMoves(player);
    if (game.isTurn(player)) {
    	int bestval = -1000;
    	for (int i = 0 ; i < moves.size() ; ++i) {
			game.makeMove(moves[i].getRow(), moves[i].getColumn(), player);
			int tmp = minimax(game, depth-1, game.opposite(player), maxing);
			if (tmp > bestval) {
				bestval = tmp;

			}
			game.undoMove();
		}
		return bestval;
    }
    else {
    	int bestval = 1000;
    	for (int i = 0 ; i < moves.size() ; ++i) {
			game.makeMove(moves[i].getRow(), moves[i].getColumn(), player);
			int tmp = minimax(game, depth-1, game.opposite(player), maxing);
			if (tmp < bestval) {
				bestval = tmp;
			}
			game.undoMove();
		}
		return bestval;
    }
    return 0;
}