import typing
from urllib.request import urlopen
import urllib.parse as urlparse
from urllib.parse import urlencode

import tldextract
from flask import request, current_app


def get_public_key():
    """Fetch public key from shared resource on the network."""

    public_key = urlopen(current_app.config.get("PUBLIC_KEY_URL"))  # nosec
    public_key = public_key.read()
    key = public_key.decode()
    return key


def get_allowed_root_domain() -> typing.Optional[str]:
    """Returns allowed root domain to set cookie or None."""

    root_domain = tldextract.extract(request.host).registered_domain
    if root_domain and request.host in current_app.config.get("ALLOWED_HOSTS"):
        return f".{root_domain}"

    return None


def add_url_params(url: str, params: dict) -> str:
    """Extends params in given url."""

    url_parts = list(urlparse.urlparse(url))
    query = dict(urlparse.parse_qsl(url_parts[4]))
    query.update(params)
    url_parts[4] = urlencode(query)
    return urlparse.urlunparse(url_parts)


def get_safe_repr(token: str) -> str:
    """
    Returns 10 chars from signature part of the token string
    or 10 chars from other string.
    """
    if not token:
        return ""

    parts = token.split(".")
    if len(parts) == 3:
        return f"{parts[2][:10]}**"

    return f"{token[:10]}**"