from __future__ import annotations

try:
    # Prefer external package if available
    from base58 import b58encode, b58decode  # type: ignore
except Exception:
    # Minimal fallback (compatible subset)
    ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
    ALPHABET_INDEX = {c: i for i, c in enumerate(ALPHABET)}

    def _to_bytes(value: bytes | bytearray | str) -> bytes:
        if isinstance(value, (bytes, bytearray)):
            return bytes(value)
        if isinstance(value, str):
            return value.encode()
        raise TypeError("value must be bytes or str")

    def b58encode(data: bytes | bytearray | str) -> bytes:
        data = _to_bytes(data)
        if not data:
            return b""
        n = int.from_bytes(data, "big")
        out = []
        while n > 0:
            n, rem = divmod(n, 58)
            out.append(ALPHABET[rem])
        enc = "".join(reversed(out))
        leading = 0
        for b in data:
            if b == 0:
                leading += 1
            else:
                break
        return ("1" * leading + enc).encode()

    def b58decode(data: bytes | bytearray | str) -> bytes:
        data_b = _to_bytes(data)
        if not data_b:
            return b""
        num = 0
        for ch in data_b.decode():
            num = num * 58 + ALPHABET_INDEX[ch]
        full = num.to_bytes((num.bit_length() + 7) // 8, "big")
        leading = 0
        for ch in data_b:
            if ch == ord('1'):
                leading += 1
            else:
                break
        return b"\x00" * leading + full