import re


class Handle:
    __lexicon_string_format__ = "handle"

    PATTERN = re.compile(
        r"^([a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?$"
    )
    FORBIDDEN_TLDS = [
        ".alt",
        ".arpa",
        ".example",
        ".internal",
        ".local",
        ".localhost",
        ".onion",
    ]

    __handle: str

    @property
    def valid(self) -> bool:
        return self.__handle != "handle.invalid"

    def __init__(self, handle: str):
        handle = handle.lower()
        if not self.PATTERN.match(handle):
            raise ValueError("Invalid Handle: does not match pattern")
        if any(handle.endswith(tld) for tld in self.FORBIDDEN_TLDS):
            raise ValueError("Invalid Handle: uses forbidden tld")
        if handle.endswith(".invalid") and not handle == "handle.invalid":
            raise ValueError(
                "Invalid Handle: '.invalid' tld may only be used with 'handle.invalid'"
            )
        self.__handle = handle

    @property
    def labels(self) -> list[str]:
        return self.__handle.split(".")

    def __str__(self) -> str:
        return self.__handle

    def __repr__(self) -> str:
        return f"Handle({str(self)})"