import os
import textwrap

from . import constants, typings


def get_private_key_content(private_key: typings.PrivateKey) -> bytes:
    """
    Get private key content from the provided private key, which is a string
    representing any of the following:
        - A path to a private key file.
        - A base64-encoded private key (single line, no headers/footers).
        - The private key itself (PEM format).
    Always returns bytes with NO trailing newline.
    """
    private_key = private_key.strip()
    if not private_key:
        raise ValueError("Private key cannot be empty.")
    if private_key.startswith("-----BEGIN"):
        # Already PEM format
        return private_key.rstrip("\n ").encode("utf-8").rstrip(b"\n")
    elif os.path.exists(private_key):
        # File path
        with open(private_key, "rb") as f:
            return f.read().rstrip(b"\n ")
    else:
        # Assume it is base64-encoded and no line breaks, reconstruct PEM
        pem = (
            constants.PRIVATE_KEY_HEADER.decode("utf-8")
            + "\n".join(textwrap.wrap(private_key, 64))
            + constants.PRIVATE_KEY_FOOTER.decode("utf-8")
        )
        return pem.encode("utf-8").rstrip(b"\n")