ai.py

from tetris import check_collision, COLS, join_matrices, rotate_clockwise
import heuristic
from collections import namedtuple

Move = namedtuple('Move', ['x_pos', 'rotation', 'result'])


class AI(object):
    def __init__(self, tetris):
        self.tetris = tetris
        self.heuristics = {
            heuristic.num_holes: -496,
            heuristic.num_blocks_above_holes: 897,
            heuristic.num_gaps: -19,
            heuristic.max_height: -910,
            heuristic.avg_height: -747,
            heuristic.num_blocks: 174,
        }
        self.instant_play = True

    def board_with_stone(self, x, y, stone):
        """Return new board with stone included"""
        return join_matrices(self.tetris.board, stone, (x, y))

    def intersection_point(self, x, stone):
        """Find the y coordinate closest to the top where stone will collide"""
        y = 0
        while not check_collision(self.tetris.board, stone, (x, y)):
            y += 1
        return y - 1

    @staticmethod
    def max_x_pos_for_stone(stone):
        """The furthest position you can move stone to the right"""
        return COLS - len(stone[0])

    @staticmethod
    def num_rotations(stone):
        """The number of unique rotated positions of stone"""
        stones = [stone]
        while True:
            stone = rotate_clockwise(stone)
            if stone in stones:
                return len(stones)
            stones.append(stone)

    def utility(self, board):
        return sum([fun(board) * weight for (fun, weight) in self.heuristics.items()])

    def all_possible_moves(self):
        moves = []
        stone = self.tetris.stone
        for r in range(AI.num_rotations(stone)):
            for x in range(self.max_x_pos_for_stone(stone) + 1):
                y = self.intersection_point(x, stone)
                board = self.board_with_stone(x, y, stone)
                moves.append(Move(x, r, board))
            stone = rotate_clockwise(stone)
        return moves

    def best_move(self):
        return max(self.all_possible_moves(), key=lambda m: self.utility(m.result))

    def make_move(self):
        """Move the current stone to the desired position by modifying TetrisApp's state"""
        tetris = self.tetris

        move = self.best_move()

        tetris.lock.acquire()
        for _ in range(move.rotation):
            tetris.stone = rotate_clockwise(tetris.stone)
        tetris.move_to(move.x_pos)
        if self.instant_play:
            tetris.stone_y = self.intersection_point(move.x_pos, tetris.stone)
        tetris.lock.release()