from typing import Generator, List, Tuple, Optional
from re import compile, Pattern
from zlib import crc32


class CRC32(object):
    NAME: str = "CRC32"
    EXT: List[str] = [".sfv"]
    SYNTAX: List[Pattern] = [
        compile(r'^;*$'),
        compile(r'^.* [0-9a-fA-F]{8}$')
    ]
    REGEX: Pattern = compile(r'[0-9a-fA-F]{8}')

    def __init__(self):
        self.cksum: int = 0

    def gensum(self, data: bytes):
        self.cksum = crc32(data, self.cksum)

    def reset(self):
        self.__init__()

    def __repr__(self) -> str:
        cstring = str(hex(self.cksum))[2:].upper()
        return ''.join([((8 - len(cstring)) * "0"), cstring])

    def __eq__(self, other) -> bool:
        return self.__repr__() == other.upper()