from __future__ import annotations

import re

"""The template to match hex strings of the specified length."""
HEX_TEMPLATE = "(?:[0-9a-f]{{2}}){{{length}}}"

"""Regex patterns to validate values of the specified cookies."""
VALID_COOKIES = {
    "auth_token": re.compile(HEX_TEMPLATE.format(length=20)),
    "ct0": re.compile(HEX_TEMPLATE.format(length=80)),
}

"""The regex pattern to extract keys and values of all required cookies."""
COOKIES_PATTERN = re.compile(
    r"\s+({keys})\s+({values})$".format(
        keys="|".join(VALID_COOKIES.keys()), values=HEX_TEMPLATE.format(length="20,80")
    ),
    re.MULTILINE,
)


def load_cookies(path: str) -> dict[str, str]:
    """Load cookies from the specified path.

    Compatible with cookies file in Netscape format.
    More details of the format: https://curl.se/docs/http-cookies.html

    - path: The path to the cookies file.

    - return: A `dict` of keys and values of all required cookies.

    - raise RuntimeError: If the cookies file failed to load.
    """
    try:
        with open(path, encoding="utf-8") as f:
            return dict(COOKIES_PATTERN.findall(f.read()))
    except OSError as e:
        raise RuntimeError(f"Cannot load cookies from file: {e.filename}") from e


def validate_cookies(cookies: dict[str, str]) -> None:
    """Validate the specified cookies.

    - cookies: The cookies to be validated.

    - raise TypeError: If there were missing or extra cookies.
    - raise ValueError: If there were invalid cookies values.
    """
    if missing := VALID_COOKIES.keys() - cookies.keys():
        raise TypeError(f"Missing required cookies: {', '.join(missing)}")
    if extra := cookies.keys() - VALID_COOKIES.keys():
        raise TypeError(f"Extra cookies: {', '.join(extra)}")
    if invalid := {
        key
        for key, value in cookies.items()
        if not VALID_COOKIES[key].fullmatch(str(value))
    }:
        raise ValueError(f"Invalid cookies: {', '.join(invalid)}")