"""Shape classifier for the two observed `__NS_sig3` families."""

from __future__ import annotations

from enum import Enum


API_10418_SIG3_HEX_LENGTH = 48
H5_SIG3_HEX_LENGTH = 68


class Sig3Shape(str, Enum):
    API_10418 = "api_10418"
    H5_ENVELOPE = "h5_envelope"
    UNKNOWN = "unknown"


def _is_hex(value: str) -> bool:
    try:
        int(value, 16)
    except ValueError:
        return False
    return bool(value)


def classify_sig3(value: str | bytes | bytearray | None) -> Sig3Shape:
    """Classify `__NS_sig3` by confirmed wire length."""

    if value is None:
        return Sig3Shape.UNKNOWN
    if isinstance(value, (bytes, bytearray)):
        text = bytes(value).hex()
    else:
        text = str(value).strip()
    if not _is_hex(text):
        return Sig3Shape.UNKNOWN
    if len(text) == API_10418_SIG3_HEX_LENGTH:
        return Sig3Shape.API_10418
    if len(text) == H5_SIG3_HEX_LENGTH:
        return Sig3Shape.H5_ENVELOPE
    return Sig3Shape.UNKNOWN


def is_api_10418_sig3(value: str | bytes | bytearray | None) -> bool:
    return classify_sig3(value) == Sig3Shape.API_10418


def is_h5_sig3(value: str | bytes | bytearray | None) -> bool:
    return classify_sig3(value) == Sig3Shape.H5_ENVELOPE


__all__ = [
    "API_10418_SIG3_HEX_LENGTH",
    "H5_SIG3_HEX_LENGTH",
    "Sig3Shape",
    "classify_sig3",
    "is_api_10418_sig3",
    "is_h5_sig3",
]