from dataclasses import dataclass
from copy import deepcopy


@dataclass
class Coordinate:
    x: int
    y: int

    def __add__(self, other):
        return self.__class__(
            self.x+other.x,
            self.y+other.y
        )


class Identicon:
    WIDTH = 17
    HEIGHT = 9
    SYMBOLS = ' .o+=*BOX@%&#/^'
    START_SYMBOL = 'S'
    END_SYMBOL = 'E'
    BISHOP_START = Coordinate(8, 4)

    MOVES = {
        0: Coordinate(-1, -1),  # 00 ↖
        1: Coordinate( 1, -1),  # 01 ↗
        2: Coordinate(-1,  1),  # 10 ↙
        3: Coordinate( 1,  1),  # 11 ↘
    }

    def __init__(self, data):
        self._data = data
        self._grid = [[0] * self.WIDTH for _ in range(self.HEIGHT)]
        self._bishop_position = deepcopy(self.BISHOP_START)
        self._end_position = None

    def calculate(self):
        for command in self._get_commands():
            self._execute(command)
        self._end_position = self._bishop_position

    def _get_commands(self):
        commands = []
        for octet in self._data:
            commands.extend([
                octet        & 0b11,  #  00   00   00  [00]
                (octet >> 2) & 0b11,  #  00   00  [00]  00
                (octet >> 4) & 0b11,  #  00  [00]  00   00
                (octet >> 6) & 0b11,  # [00]  00   00   00
            ])
        return commands

    def _execute(self, command):
        move = self.MOVES[command]
        self._bishop_position = self._ensure_within_grid_borders(self._bishop_position + move)
        self._increment_current_position()

    def _ensure_within_grid_borders(self, coordinate: Coordinate):
        coordinate.x = max(0, min(self.WIDTH-1, coordinate.x))
        coordinate.y = max(0, min(self.HEIGHT-1, coordinate.y))
        return coordinate

    def _increment_current_position(self):
        self._grid[self._bishop_position.y][self._bishop_position.x] += 1

    def __str__(self):
        icon = self._header+'\n'
        for y, row in enumerate(self._grid):
            icon += '|'
            for x, cell in enumerate(row):
                icon += self._determine_symbol(Coordinate(x, y), cell)
            icon += '|\n'
        icon += self._header

        return icon

    @property
    def _header(self):
        return f'+{self.WIDTH*"-"}+'

    def _determine_symbol(self, coordinate, cell):
        symbol = self.SYMBOLS[min(cell, len(self.SYMBOLS)-1)]
        if coordinate == self.BISHOP_START:
            symbol = self.START_SYMBOL
        elif coordinate == self._end_position:
            symbol = self.END_SYMBOL

        return symbol